Date: Wed, 06 Jan 1999 08:14:22 -0800
From: Eric Westland <ewestland@altavista.net>
Subject: Re: COZY: Epolite 9935 substitute

While hot glue is not a replacement for the 5 minute epoxy, I found that in many
of the applications you are just using the 5 min. to tack parts together and the
hot glue did just fine.

Militch@aol.com wrote:

> I am using MGS285 epoxy and like it a lot.  It is easy to use, flows well, and
> has no offensive odor.  This is important because I am working in my basement.
> Unfortunately the 5 minute epoxy (Epolite 9935) that I use to glue pieces of
> foam together occasionally is not so nice.  The hardener stinks terribly, and
> the smell goes through the house in an instant. Senior management (my wife and
> kids) have handed me a cease and desist notice.  Can anyone suggest an
> alternative that has no odor?  Cost is no object since I only use the stuff in
> small quantities.
>
> Thanks,
>   Peter Militch  Chapter 4, bulkheads.

From: Epplin John A <EpplinJohnA@jdcorp.deere.com>
Subject: RE: COZY: Epolite 9935 substitute
Date: Wed, 6 Jan 1999 10:31:55 -0600 

Try the System Three quick cure 5 minute epoxy.  Almost no odor.  Only
drawback I have found is the B part will harden on its own in about a year,
order the smaller kits, I believe they are one pint total.  I am not sure,
but maybe heating the stuff will get it back into usable form again,
anybody out try that?

John epplin   Mk4   #467

> -----Original Message-----
> From:	Militch@aol.com [SMTP:Militch@aol.com]
> I am using MGS285 epoxy and like it a lot.  It is easy to use, flows well,
> and
> has no offensive odor.  This is important because I am working in my
> basement.
> Unfortunately the 5 minute epoxy (Epolite 9935) that I use to glue pieces
> of
> foam together occasionally is not so nice.  The hardener stinks terribly,
> and
> the smell goes through the house in an instant. Senior management (my wife
> and
> kids) have handed me a cease and desist notice.  Can anyone suggest an
> alternative that has no odor?  Cost is no object since I only use the
> stuff in
> small quantities.
> 
> 
> Thanks,
>   Peter Militch  Chapter 4, bulkheads.

Date: Wed, 06 Jan 1999 12:15:21 -0500
From: bil kleb <w.l.kleb@larc.nasa.gov>
Subject: Re: COZY: Epolite 9935 substitute

Militch@aol.com wrote:
> 
> I am using MGS285 epoxy [...] it has no offensive odor.

how would you know?  don't you wear a respirator?!  i can't stand the
thought of losing my ten-year-plus dream to an allergic reaction have
way through building.  carbon monoxide has no odor.  please review
the archives on epoxy, safety, etc.

-- 
bil <mailto:w.l.kleb@larc.nasa.gov>

Date: Wed, 06 Jan 1999 12:41:32 -0500
From: Bulent Aliev <atlasyts@bellsouth.net>
Subject: Re: COZY: Epolite 9935 substitute

"While hot glue is not a replacement for the 5 minute epoxy, I found
that in many
of the applications you are just using the 5 min. to tack parts together
and the
hot glue did just fine."

I use that too and like it. Just that if you have to sand it later will
gum up your sand paper
Bulent

Date: Wed, 06 Jan 1999 14:46:25 -0500
From: bil kleb <w.l.kleb@larc.nasa.gov>
Subject: Re: COZY: Epolite 9935 substitute

someone responded (privately):
> 
> I wore a respirator when I used Saf-t-poxy that stuff stinks

my point was (supposed to be) that certain stuff kills without
any detectable odor.  what does the msds sheet say for MGS?

> I too am using MGS and he is right there is No Odor

odor isn't the only thing to consider.  2427 had low odor, but
plenty of folks doing layups in their basements chose to wear
respirators.

> I too Dont use a respirator with the MGS

that's fine by me, it's your choice.

> But the hands.... I wear gloves to protect myself from buildup
> from an allergic reaction.

good plan, just remember that _latex_ gloves have been shown to
pass components of our epoxy systems...

> not Going to get into a pissing contest... But

:)

> If your Not using the MGS epoxy Dont make Comment on it....

i apologize, i was not intending to make a comment on MGS. i was
just trying to point an apparently new builder to the archives
to raise his awareness of safety considerations...  and offering
a brief glimpse of the rationale behind what i have chosen to do.
(which is what this group is all about, no?)

> this is my second cozy.. and I have helped a few Friends Build Longs..
> I have used RAE, Saf-t-poxy and this new MGS...and from personal
> experience.. the MGS is the best

i don't understand "best", best in what respect?  pot-life, storage
properties, humidity sensitivity, safety, odor, viscosity, etc.?

> however personal saftey always comes first.

my point exactly.

> Maybe I,m lucky I have not had any allergic reactions to any
> of the above.

that is what they say: it is not a matter of "if", but when; and it
depends on the person how soon "when" is.  however, once you find
out "when", it's too late.  plenty of people have had to put
their dream projects up for sale...

> I have more Problems with fumes from the heaters in the shop
> than I do with the Epoxy.

to each his own. personally, i like the smell of kerosene...  :)

-- 
bil <mailto:w.l.kleb@larc.nasa.gov>

From: cdenk@ix.netcom.com
Date: Wed, 6 Jan 1999 17:21:48 -0600 (CST)
Subject: Re: COZY: Epolite 9935 substitute

Someone said <Hot glue for foam joints>
The epoxy most  times functions as structural adhesive to transfer shear loads (parallel to the 
joint plane), I wouldn't want to trust hot glue for that! If you were to cut a section, say a 1 foot 
wide perpendicular to direction of travel, piece of wing forward of the spar. All the loads (lift) 
have to be transfered by foam and fiberglass skin to the spar. The skin takes the bending in 
compression (and partly by foam) and tension (all by skin). The vertical load is carried entirely 
(glass does so little, it is neglected) by the foam. This same principle carry through nearly 
everywhere, including the fuselage bulkheads and sides.  

Date: Wed, 06 Jan 1999 19:57:24 -0600
From: James Russell <fshort@flash.net>
Subject: Re: COZY: Epolite 9935 substitute

cdenk@ix.netcom.com wrote:
> 
> Someone said <Hot glue for foam joints>
> The epoxy most  times functions as structural adhesive to transfer
> shear loads (parallel to the....

Hi to all:

	In general, I just wanted to say thanks to all for making this list
interesting reading! Having many views of a problem is certainly a help
to me.
	I think people asking for input regarding changes is so much better
than just substituting blindly. I work on corporate jets and
the Structural Repair Manuals are very specific about approved
materials, methods, etc.
 
	I certainly don't want all the paperwork, expense, and older technology
of the certified aircraft world in homebuilding, however!

	Anyway, I once was using Hysol 934 EA to bond foam ribs to a
spar (racing car wing). I realized since the allowable of the foam
was only 40 psi I was spending alot ($90 kit) for 5-6 ksi epoxy bonds
much stronger than the foam. 
 	However, I remember Rutan speaking to this issue in the Long-Eze plans
saying that shear loads, although low, must be carried by the foam so no
joining foam with spray adhesive, etc.

	I guess the old chain and its weakest link idea applies...

Date: Wed, 6 Jan 1999 23:11:50 -0500
Subject: COZY: Safety and MGS
From: dhill36@juno.com (Dana Hill)

To any of the new Cozy Builders,
	Although I am only about a year into the project (and only on Ch
5), I have reviewed all the archives and other material on
safety/exposure to epoxy and discussed this issue with other Cozy
builders.  There is much hard learned wisdom in those archives.  I to
quickly found out that MGS epoxies have little odor.  However as Bill K.
mentioned this really isn't a case of no odor therefore no concern. 
These faint fumes are dangerous in the long term and this is a multi-year
project for most of us.  During layups I have always worn a respirator
and on the hands cotton liner gloves, then butyl gloves and then latex or
vinyl gloves to maximize the life of the $ butyl gloves and also safety
glasses.  I feel its a small price to pay for such a huge return (your
health).  It is very likely that any experienced builder will give you
the same story.  
Hope everyones staying warm and productive!
____________________________________________________
Dana Hill
Cozy IV #676
  

___________________________________________________________________
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Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
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From: cozy623@juno.com
Date: Sat, 9 Jan 1999 17:58:42 -0700
Subject: COZY: mgs

I like the mgs alot but it wants to ingest tons of air with stippling and
stirring and stuff.  I bet you could make whipped cream out of it if you
really tried.  Any hints?  Jeb

Date: Sun, 10 Jan 1999 10:37:30 -0600
From: "Joseph H. Hart IV" <jodyhart@communique.net>
Subject: Re: COZY: mgs

Jeb:

    I've been using MGS 285 and am currently almost finished with Chapter 6
(currently waiting for more supplies -- I haven't been able to figure out how
to get by with the minimal supplies suggested by the plans!).  I have noticed
that the MGS gets a lot of air in it when it is mixed; however, I haven't had
a problem with air in my layups.  I have used a hair dryer a lot and this may
account for the fact that I haven't had an air bubble problem.  Have you been
using a hair dryer?  If not, give it a try.  I think the heat gets the
viscosity low enough for the air to easily escape.  I've also peel-plied just
about everything.  I can't say whether this has helped minimize entrapped air
but it is possible that it has helped as well.

    Good luck with your project.
--
Jody Hart
New Orleans, LA

Cozy Mark IV plans no. 648
Chapter 6, see latest progress at:
home.gs.verio.net/~jodyhart/home.html
N359JH (reserved)


From: Militch@aol.com
Date: Sun, 10 Jan 1999 14:21:42 EST
Subject: Re:  COZY: mgs


In a message dated 1/9/99 8:58:36 PM, you wrote:

>I like the mgs alot but it wants to ingest tons of air with stippling and
>stirring and stuff.  I bet you could make whipped cream out of it if you
>really tried.  Any hints?  Jeb

I am surprised.  I use the MGS epoxy and am impressed at the lack of air
bubbles when I mix it up.  I keep it in a heated cabinet that stays around 85
to 88 degrees.  Do you have it that warm when you mix it?

Peter Militch Mark IV #740 Chapter 4 Bulkheads

From: cozy623@juno.com
Date: Sun, 10 Jan 1999 15:59:58 -0700
Subject: COZY: mgs

Duh!  It is the cold.  I keep my garage at a little over 80 but the epoxy
didn't act this way when it was hotter.   Thanks.  Jeb

Date: Mon, 11 Jan 1999 09:40:28 -0800
From: Frank Johanson <ics@ime.net>
Subject: Re: COZY: mgs

Hi Jeb
I have the same problem, I have to heat the epoxy and work with the room 80
to 85.
What part of the country are you in ? Auburn Me. here.

cozy623@juno.com wrote:

> Duh!  It is the cold.  I keep my garage at a little over 80 but the epoxy
> didn't act this way when it was hotter.   Thanks.  Jeb



From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: COZY: "Overheating" epoxy
Date: Thu, 14 Jan 1999 09:22:44 -0600

In a post with the SUBJECT:  COZY:Canard Spar
> Bill Kastenholz wrote:
> How hot can the epoxy get before "overheating" it?
> 
The boiling point of uncured liquid resin is over 400F and the curing agents
are often less - 300F or so.   Theoretically, the blended resin and curing
agent will have an initial boiling point somewhere in the middle.
Obviously, you don't ever want to boil the resin / curing agent combination.


In working with a heat gun during laminating, the goal is to simply reduce
the viscosity of the resin to help facilitate wet out, and to achieve the
desired resin/glass ratio.    The viscosity of epoxy resins drop quickly
from room temperature to about 140F.  Above that, it is pretty flat line.
So, heating the resin above 140F has no significant benefit.  

So in my book - anything over 140F is - "overheating it"  and 100F is plenty
hot enough for our work.

NOW - from a cured resin perspective.....

Most cured epoxy resins can be exposed to temperatures as high as 450F for
short periods of time (up to 12 hrs.) without serious damage to the polymer
matrix.  However, over extended periods of time, it will begin to slowly
break down by thermal oxidative reduction and physical properties will
diminish over time (2-10 weeks).   At 650F, molecular cleavage begins, and
it will decompose into volatiles like, carbon monoxide, carbon dioxide,
water, cyclopentadiene, and methylcyclopentadiene.   Above that temperature
it simply happens faster and produces less water.  

To determine the glass content of a epoxy/fiberglass composite, the industry
performs what we sometimes call a "burnout".    A pre-weighed specimen of
the composite is placed in a ceramic crucible and placed in a furnace that
usually starts out at 600F and slowly increased to about 800F.   In about 6
hrs., the epoxy resin surrounding the fiberglass is completely burned away -
carbonized and then oxidized.  What is left is nothing but the fiberglass.
Re-weighing the crucible's contents yields the amount of glass that was in
that specimen.  

Gary Hunter
EAA Technical Counselor
Shell Chemicals Epoxy Guy

Date: Tue, 26 Jan 1999 12:37:38 -0500
From: "Johnson, Phillip" <phillip.johnson@lmco.com>
Subject: COZY: Transport of epoxy in cold weather

I'm down to my last gallon kit of ez-poxy II and I guess that I need to
order some more soon. I live in Canada where the temperature gets to
-30C overnight on occasions and is more typically -20C. If I order new
epoxy at this time of year there may be periods in which the temperature
may get close to these extremes. What happens to the epoxy? I know that
it may crystallize and that can be recovered by controlled heating but
can permanent damage result if it gets too cold?

Phillip Johnson
Cozy MKIV RG	 #30



From: cdenk@ix.netcom.com
Date: Tue, 26 Jan 1999 18:17:25 -0600 (CST)
Subject: Re: COZY: Transport of epoxy in cold weather

was said <?? Transportation temp. of epoxy> You might check with your carrier (UPS, FEDEX), the 
might be able to guarantee for a price the temperature, since they do lots of things where temp is 
critical, from food, and flowers to drugs. The order fastest way when warm front is moving through.

Date: Tue, 26 Jan 1999 22:57:58 -0500
From: "Marc J. Zeitlin" <marcz@ultranet.com>
Subject: Fwd: COZY: Transport of epoxy in cold weather

Phillip Johnson wrote:

>can permanent damage result if it gets too cold?

Everything I've ever seen says no - heating it up gently (or not so gently)
will un-crystallize the hardener (I don't think the resin will crystallize
- at least I've never seen it do so, and I've had the hardener crystallize
on me a couple of times).  I hope Gary Hunter will weigh in here with
confirmation.

To tell you the truth, I think these epoxies (at least the EZ10/84 that I'm
now using - I won't speak for the  are pretty insensitive to most anything
we can do to them with respect to temperatures, mix ratios, etc.  Before
anyone jumps down my throat, I'm in no way claiming that we should pay no
attention to mix ratios, keeping temperatures in the proper range, mixing
times, etc.

I'll say is that in tests that I've done with purposefully wrong ratios
(off by 20% or so), poor mixing (just barely visually mixed to a consistant
color), and temperature extremes (warmed up hardener, or really thick goopy
hardener), I've never NOT had the epoxy harden and pass the "scratch" test,
as described in the plans.

I will also state that I do, in fact, use an epoxy pump that is accurate to
a couple of % at the worst, keep the epoxy at a constant 80 F, and mix like
mad :-).

--
Marc J. Zeitlin           marcz@ultranet.com
                          http://www.ultranet.com/~marcz/

From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Transport of epoxy in cold weather
Date: Wed, 27 Jan 1999 07:11:52 -0600

> Phillip Johnson wrote:
> 
> >can permanent damage result if it gets too cold?
> 
Marc J. Zeitlin  wrote:

> Everything I've ever seen says no - heating it up gently (or not so
> gently)
> will un-crystallize the hardener (I don't think the resin will crystallize
> - at least I've never seen it do so, and I've had the hardener crystallize
> on me a couple of times).  I hope Gary Hunter will weigh in here with
> confirmation.
> 
Don't worry about frozen resin / curing agent and do not pay for temperature
controlled shipping.   They may (or may not) crystallize during cold
shipping conditions.  However, they will reconstitute with gentle warming
and be as good as new.   Never use a resin or curing agent that has any
evidence of crystallization.

If the container is tightly sealed, you can simply immerse the resin or
curing agent container in a bucket of Hot tap water.  Replenish the hot
water as necessary to keep the temperature up.   Occasionally, mildly shake
or rotate the resin container to stir the contents.  

Mix ratios are very important.  Do not compromise.   If in doubt, throw it
out.   

Gary Hunter
Shell's Epoxy Guru

From: "Chris Byrne" <jcbyrne@ozemail.com.au>
Subject: COZY: MGS Epoxy
Date: Fri, 26 Feb 1999 14:21:17 +1100

Builders using MGS epoxy

I have had a problem with cloudy resin (L335), and thought I would share the
results with you.

I know there is a lot in the archives about this problem (with other
epoxies) but from what I can see it deals only with the hardeners, not
resin.

Below is the e-mail I sent to Johannes Meunier at MGS in Stuttgart and his
reply as well as my findings.

This is a bit long winded but some of you may find it useful and it comes
straight from the horses mouth.
The reply came from MGS within minutes of them opening for business and the
offer of testing implies great customer support.

Dear Johannes

I have a quick question about the L335 resin.
I have noticed that the last 1cm (3/8 inch) in the bottom of my epoxy pump
is very
milky/cloudy and is a lot thicker than the rest of the resin.(almost sludge)
I have the same problem in a 2 L plastic container that has some resin
in it.
The resin has been in the pump and container for about 6 weeks.
The container has been full and the cap on it for the entire time, so I do
not think that it has been exposed to too much air or humidity, and the temp
has been between 17 and 30 degrees C ever since I received the epoxy from
you.

What is causing this cloudiness and is it a normal occurrence?
Is it any of the key components of the resin falling out of solution?(ie are
all of the important bits of the resin ending up in the bottom)
Should I discard the cloudy resin or mix it in with the rest?
Has the strength of the epoxy been compromised?
If this is happening in the bottom of these two containers it is probably
also occurring in the bottom of my 30KG Hobbock.

The hardener does not have this problem.

I have no problem with discarding the cloudy/thick resin, but am worried
that the strength is being compromised.

Otherwise the epoxy is very good too use and I seem to be getting good
results.

Regards
Chris Byrne
Sydney

Dear Chris,

I can imagine two possible situations that would explain the cloudiness in
your
resin. The first and most likely one is, that the resin simply has
crystallised.

Epoxy resins, when exposed to temperatures lower than 15 degrees  Celsius
may
start to do this. It is basically the same as water when it freezes. It may
have
started during transportation and continued during storage.
The way to get out of this is simply to warm up the resin to approx 60-70
degrees
Celsius. Keep the temperature for a couple of hours and stir or shake the
contents a little This will dew up the resin - if it is crystallisation. You
should have a clear resin afterwards.
The second possibility would be a contamination of the material. For example
a
contamination with hardener that happened by mistake or that for whatever
reason
the resin started to dissolve the plastic container (although weve never
experienced that before). The containers should be made of Polyethylene
(HDPE),
its the best material to resist most aggressive chemicals.

If you cant clarify the resin by heating it up, the best procedure would be
to
mix it with the equivalent amount of hardener, cure it and then put it in
the
garbage. Please do only scrap the resin as it has cured, the liquid resin
and
hardeners are considered to be environmental dangerous.

Most likely it will only be crystallisation, this is normal. However, dont
use
the white stuff. Clarify it before use.
If you want to be 100% sure I can offer you the following. We can measure
the
quality of a cured resin sample and tell if it has been properly mixed,
resp. if
the resin or hardener quality has deteoriated. If a resin sample we obtain
shows
the normal quality, you can be sure that it has it full properties. I can
offer
you to send me a sample of the cured resin, for example cut offs from parts
that
you made. Some grams is enough.  We both want you to have a high quality
airplane!

If I can be of any further assistance, please let me know.

Regards,
Johannes


Armed with that info I sat the 1/2 gallon container of resin in a pot on the
stove and within 30mins it was as clear as if looking into a glass of water.
The resin had never been this clear, even the first time it  was used.

I then bought my epoxy pump upstairs and sat it on my oil filled electric
heater, placed a couple of towels over it to keep the heat in, again it was
crystal clear in about 30 mins.
I can now see the outlet valve clearly, before it I could just make it out
through the haze.
I think the temp would have been about 55-60C (130F).

The pump had previously been kept at 30C (85F) with a globe in a box (globe
on a couple of hours before use).

For those of you using this epoxy it may be worth warming up your resin and
observing the difference in clarity.


I intend to send a sample of cured resin (cloudy resin) to MGS and have it
tested. And will let you know the out come.


Chris Byrne
Sydney








From: "John Slade" <jslade@adelphia.net>
Subject: Re: COZY: MGS Epoxy
Date: Thu, 25 Feb 1999 23:57:30 -0500

Chris,
Thanks for posting your experience with L335. I have my first delivery of
the stuff coming in next week. Could you also post the email address of
Johannes Meunier at MGS in case I, or others, want to contact him?
John Slade

From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: COZY: MGS Epoxy / Crystallization
Date: Fri, 26 Feb 1999 09:42:31 -0600

Chris Byrne wrote:

> Builders using MGS epoxy
> 
> I have had a problem with cloudy resin (L335), and thought I would share
> the
> results with you.
> 
> I know there is a lot in the archives about this problem (with other
> epoxies) but from what I can see it deals only with the hardeners, not
> resin.
> 
Only some hardeners crystallize (Safe-T-poxy / EZ-poxy type in particular) -
but ALL liquid epoxy resins are susceptible to crystallization.   The base
component of all liquid epoxy resins are in fact - "meta-stable super cooled
liquids" - with melting points between 110F and 140F.  Which means at
temperatures below their melting points, they are in a physical state
unnatural to their molecular structure.  And as such, they will try to
revert to the crystallized state when conditions are correct.  Generally,
cool temperatures appears to be the most significant cause for
crystallization.   In actuality, it is cool temperatures combined with
constant cycling that really accelerates the crystal growth process.  Cool
nights, warm days, etc.    Therefore, to retard crystallization, it is best
to keep the resin stored at as constant a temperature as practical -
preferably 75F or better.  Below are some of my earlier comments on shop
temperatures. 

Crystallization occurs long before any VISUAL evidence (haziness) indicates
so.  The only way to detect it prior to appearance of visual indicators is
to measure  the resins viscosity.   It will steadily increase over time, and
will almost double before haziness starts to set in.   SO,  if you notice a
marked increase in the resin's viscosity (assuming temperature is not a
factor) then you have the beginnings of crystallization.   

Resin crystals are comprised of the purest molecules of resin (n=0 if your a
chemist) in the container, and as such they are more dense and tend to
settle to the bottom.  The composition of remaining liquid on top is now
different from what it was supposed to be.   Primarily, it will be higher in
viscosity and reactivity (shorter pot life).    In haste, it may be tempting
to use the (somewhat clear) resin on top in order to "get the job done" and
reconstitute the remaining contents later.   Although the part you made is
probably OK, this is not a good deal overall.   It is best to reconstitute
the container by heating AND agitating the contents to redistribute the
purest molecules throughout the resin.  

Every vendor (MGS, Aeropoxy, PTM&W, EZ-poxy, etc) of formulated epoxy resins
like to believe their formulas are shelf stable and resist crystallization
sufficiently enough to not be a concern for the end user.   However, in my
job, I speak with many surprised vendors on how to deal with their
unexpected crystallization problems.   

When you receive a shipment of resin from Wick's Aircraft Supply, there is
no way to tell how long it has been sitting around,  what temperature is was
stored at, or what state it is in.  It may be clear, but the viscosity may
be higher than it is supposed to be.   Therefore,  it would be a good
practice to "reconstitute" or de-crystallize the unopened containers prior
to using.   

Here are some excerpts from my replies to this issue on Canard-Aviators.com.
It is long but worth reading. 

	In my job, this is the time of the year (fall/winter) we start
hearing people cry -"my epoxy won't pour out of the bottle any more", or
"it won't harden", or "it turned to wax", or "can I exchange it for fresh".

	...............Keeping the resin from crystallizing is only a small
portion of the temperature control picture.  The temperature of "ALL" the
materials in your shop is just as important.  The temperature of the
reinforcement (fiberglass) and the foam directly effects the temperature of
the resin.  Even though the resin you just mixed may be 80F, as soon as it
hits the fiberglass and foam, it immediately cools off to the temperature of
the foam and fiberglass.  The only effective way to manage the temperature
of these materials is to control the temperature of the room.

	From a resin perspective, cool temperatures:

	1)	Increases viscosity that effects the resin/glass ratio -
cooler temperatures tend to make heavier lay-ups

	2)	Lengthens pot life / cure times - reaction rate doubles
every 10C (18F) - anything below 65F is taboo

	3)	increase surface tension (slows fiberglass fabric wet-out -
tends to make heavier lay-ups) 

	If you shop isn't temperature controlled, I would make it so.  You
will probably reduce the construction time on your airplane by a year or
better as the shop will be more hospitable.    Now that I have said that,
let's talk about resin crystallization.

	Keeping the resin warm will only "retard" the crystallization of the
epoxy resin.  The only way to completely prevent crystallization is to keep
the resin above 120F.  Storing resins at this temperature will not harm them
at all.  In fact, we (Shell Chemical) store our liquid epoxy resins in bulk
at 160F for months at a time.  We do this to reduce the viscosity for
pumpability.  However, this is both impractical and way too warm for you to
work with.  

	Whether you have a heated shop or not, all you NEED to do for
"retarding" crystallization is keep the resin in a "hot box" or constant
temperature box at about 80-90F.  You can keep it warmer if you want, but I
would not go over 120F.  To keep the resins warm I recommend building a hot
box, or make one out of an old "Igloo" cooler by hanging a (small) light
bulb inside with a small fan from a computer CPU (Radio Shack) to circulate
the air. Depending on the size of the box and the actual temperature of your
shop,  you'll need a different wattage light bulb.  Just start with a 25
watt bulb and work your way up until you get the temperature you desire.  If
your using the hot box for storage, or "de-crystallizing the resin" 120F is
good.   Otherwise,  80-90F is just fine.   IF, you want, you can use this
kind of hot box for your (ugh) epoxy pump too.   Turn the "Igloo" on its
side and mount it to the wall so the lid hinges upward.    Put the pump
inside with the hanging light bulb and the circulating fan.  Open to pump
resin, close it when your done. 

	Below is the word advice we put on the shelf life statement for all
our liquid epoxy resins: 

		Refrigeration will not enhance the storage stability of this
product. Furthermore, EPON 862 is a super-cooled liquid and is inherently
susceptible to crystallization, particularly at temperatures below 50?F.
Therefore, refrigerated storage is neither beneficial nor necessary for this
product.

		Crystallized resin is evidenced by a product visual
appearance that can range from a hazy liquid to a waxy semi-solid.   Resin
that has crystallized can be reconstituted by gentle warming of the entire
container and it's contents to approximately 120-140?F until all visual
evidence of crystallization has gone away.  Upon cooling to normal ambient
temperature conditions the product will regain its original liquid state
physical properties.

Perhaps I should present a forum at Sun-n-Fun or Oshkosh this year.
Anybody interested ??

How about - Everything you wanted to know about epoxy resins - or maybe not.

KINDEST REGARDS,
Gary Hunter
Technical Service Representative   
EPOXY RESINS TECHNICAL INQUIRY
SHELL CHEMICALS, USA

Toll Free in North America   -   800-832-3766  (800-TEC-EPON)
International                        -   713-246-8295
Facsimile                            -   713-241-1606
E-Mail                                 -   gahunter@shellus.com


From: "Nat Puffer" <cozy@extremezone.com>
Subject: Re: COZY: MGS Epoxy / Crystallization
Date: Fri, 26 Feb 1999 11:05:39 -0600

Gary,
We would like to invite you to speak at our Cozy Builders Forum in Oshkosh
on Friday, July 30, 1pm, date and time to be confirmed.
Best regards,
Nat 

----------
> From: Epplin John A <EpplinJohnA@jdcorp.deere.com>
> To: 'Cozy Mailing List' <cozy_builders@canard.com>
> Subject: RE: COZY: MGS Epoxy / Crystallization
> Date: Friday, February 26, 1999 10:12 AM
> 
> 
> Gary Hunter asks:
> 
> > Perhaps I should present a forum at Sun-n-Fun or Oshkosh this year.
> > Anybody interested ??
> > 
> > How about - Everything you wanted to know about epoxy resins - or maybe
> > not.
> > 
> > 
> 	[Epplin John A]  
> 
> 	Definitely, I will be there at OSH,  not sure about Sun-n-Fun yet.  
> 	I am sure you will have a good crowd!

From: "Todd B. Acheson" <acheson@ohiou.edu>
Date: Sun, 28 Feb 1999 08:28:29 -0500
Subject: Re: COZY: MGS Epoxy / Crystallization

On Fri, 26 Feb 1999 09:42:31 -0600 "Hunter GA (Gary)  at MSXSCC" 
<GH334766@MSXSCC.shell.com> wrote:

> 
> Crystallization occurs long before any VISUAL evidence (haziness) indicates
> so.  The only way to detect it prior to appearance of visual indicators is
> to measure  the resins viscosity.   It will steadily increase over time, and
> will almost double before haziness starts to set in.   SO,  if you notice a
> marked increase in the resin's viscosity (assuming temperature is not a
> factor) then you have the beginnings of crystallization.   
> 

Are there any simple techniques to measure viscosisty that the home 
builder can use check whether cyrstallization has occurred?

----------------------
Todd Acheson
740 593-0034

acheson@ohiou.edu

From: Jim Hocut <jhocut@mindspring.com>
Subject: RE: COZY: MGS Epoxy / Crystallization
Date: Sun, 28 Feb 1999 10:24:07 -0500


>
> Are there any simple techniques to measure viscosisty that the home
> builder can use check whether cyrstallization has occurred?
>

Viscosity can be measured by timing how long it takes a given amount 
of liquid to flow through a calibrated orifice.  As a comparison such 
as is being discussed here, you could use any container with a small 
hole and time how long it takes a given size sample to flow out. 
 Then some months later use the same container and compare the 
results.  Temperature of the sample would have to be exactly the same 
each time to be able to make a comparison.

>From a practical standpoint my personal opinion is that it's better 
to avoid any problems in the first place.  Keep your epoxy in a 
hot-box, around 80 - 85 deg F and it should be just fine.  Heating 
(and stirring) the resin before first use is also a good idea.


Jim Hocut
jhocut@mindspring.com



From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: MGS Epoxy / Crystallization
Date: Mon, 1 Mar 1999 11:49:33 -0600 

Todd inquired:

> > Crystallization occurs long before any VISUAL evidence (haziness)
> indicates
> 
> Are there any simple techniques to measure viscosisty that the home 
> builder can use check whether cyrstallization has occurred?
> 
Yes, you can use a painter's viscosity cup you can buy at the paint store.
You measure the time it takes for the contents to drain through an orifice.
But, to be honest with you, it isn't worth the trouble.   It is VERY
temperature dependant, and you have to clean up the cup each time with
solvents and stuff.   That process alone is just enough of a pain you
probably won't do it again.    

Putting a sealed container of resin in a bucket of hot tap water is a lot
less messy and virtually guarantee's you have crystal free resin.   No muss,
no fuss, no worries.  

Gary Hunter



From: "kim lueck" <dlueck@execpc.com>
Subject: COZY: RAE Replacement
Date: Tue, 2 Mar 1999 06:36:35 -0600

Does anyone know where I can get 2 gallons of the RAE epoxy?  Wicks and ASS
are both listing it as no longer in production.  What is an acceptable
substitute (4 to 1ratio, I don't want to buy a new pump just to finish
attaching the turtleback).


thanks,
	Daryl Lueck	
	N797DL
	Cozy IV

From: "Bill Kastenholz" <wkasty@ix.netcom.com>
Subject: Re: COZY: RAE Replacement
Date: Wed, 3 Mar 1999 03:47:30 -0500



>Does anyone know where I can get 2 gallons of the RAE epoxy?  Wicks and ASS
>are both listing it as no longer in production.  What is an acceptable
>substitute (4 to 1ratio, I don't want to buy a new pump just to finish
>attaching the turtleback).
>
>
>thanks,
> Daryl Lueck
> N797DL
> Cozy IV
>

Hi Daryl,

    The Composite Polymer Design (CPD) epoxy is the same formula as the old
RAE.  As I understand it, just a different company producing the epoxy. I
have used this product for the last half year at least, and it has all the
same working properties of the RAE. I did call the company last year and
talked to a tech rep who convinced me to continue using it.

Bill Kastenholz
wkasty@ix.netcom.com

From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: RAE Replacement
Date: Wed, 3 Mar 1999 09:56:47 -0600 

Dave Hoefell -  800-755-8568 

St. Paul, MN  

or 

Phil Cuthbert  -  800-886-0429

Simi,  CA   

> -----Original Message-----
> From:	Michael Amick [SMTP:mkamick@wans.net]
> Sent:	Wednesday, March 03, 1999 11:01 AM
> To:	Bill Kastenholz
> Cc:	kim lueck; cozy builders
> Subject:	Re: COZY: RAE Replacement
> 
> Bill Kastenholz wrote:
> 
> > The Composite Polymer Design (CPD) epoxy is the same formula as the old
> > RAE.  ....it has all the same working properties of the RAE.
> > ....talked to a tech rep who convinced me to continue using it.
> > 
> 
> 
> Address?
> 
> Phone?
> 
> Michael Amick

From: "astrong" <astrong@mscomm.com>
Subject: Re: COZY: RAE Replacement
Date: Thu, 4 Mar 1999 08:04:08 -0800

Kent,
My son-in-law and I are building a MkIV with the active help of our
respective spouses. We are using the  CPD, RAE equivalent from WICKS Epoxy #
4426 A. Slow Hardener# 9377 and using the original pump that I used building
My COZY III ten years ago. Goodluck.WICKS contact ;Janet Stomacher
-----Original Message-----
From: Kent Ashton <kjashton@vnet.net>
To: cozy_builders@canard.com <cozy_builders@canard.com>
Date: Thursday, March 04, 1999 7:52 AM
Subject: Re: COZY: RAE Replacement


>Bill Kastenholz wrote:
>>
>>     The Composite Polymer Design (CPD) epoxy is the same formula as the
old
>> RAE.
>
>Very interesting.  There are a lot of us who like the RAE and would like
>to have a source for it.
>
>--Kent Ashton
>

From: "John Slade" <jslade@adelphia.net>
Subject: COZY: Chap 4 - MGS epoxy won't harden
Date: Sat, 6 Mar 1999 21:13:06 -0500

I'm using MGS 335 epoxy with the slow hardner.
I tried a test layup 2 days ago and it's still not hard. Today I tried
another test and left the remaining epoxy in the cup. 12 hours later the
layup is still tacky and the epoxy in the cup is still mobile. ie I can
still move the tongue depresser in it and depress the surface with my
finger.  Temperature has ranged between 62 and 75 during this period. The
epoxy is kept in a HOT box. I measured the temp in there and found it was
106f. Tomorrow I'm going to try the "fast" hardner and lower the temp in the
hot box to about 85.

Anyone have any suggestions or ideas?
Is the MGS rep who helped out a week or two ago reading this mail list?
Anyone have his email address?

I haven't done a "real" layup yet. If the epoxy doesnt cure the part is
ruined. - right?
John Slade (#757)

From: "Neal Newman" <groucho@pluto.skyweb.net>
Subject: Re: COZY: Chap 4 - MGS epoxy won't harden
Date: Sun, 7 Mar 1999 05:31:35 -0500

 Hi Chris
 it took 4 days for it to harden  when I first started to use the Mgs
epoxys....
 I found the best is to mix 50/50  the fast and slow  hardners..
when I first started using the stuff I didnt know there were 2 different
hardners...
because my First order came with the slow......
 try the 50/50  fast/slow  and you will be very happy......

Neal
-----Original Message-----
From: Chris Byrne <jcbyrne@ozemail.com.au>
To: Cozy Builders <cozy_builders@canard.com>
Date: Sunday, March 07, 1999 2:04 AM
Subject: Re: COZY: Chap 4 - MGS epoxy won't harden


>John Slade wrote
>
>I'm using MGS 335 epoxy with the slow hardner.
>>I tried a test layup 2 days ago and it's still not hard. Today I tried
>>another test and left the remaining epoxy in the cup. 12 hours later the
>>layup is still tacky and the epoxy in the cup is still mobile
>
>I have not used just the 340 (slow) hardener but acording to the company
you
>will get a pot life of 6 hrs.
>So still being able to move the stick after 12 hrs sounds may be about
right
>although it does sound a bit slow.
>The temp of 62 is probably the culprit.
>Try another test and take it to bed with you or somewhere equally as warm
>and see how it goes.
>
>The fast (335) will give a pot life of 15 mins.(starts to thicken and cloth
>will not wet out as easily)
>All my layups (until my last one) have been with a 50/50 mixture of the
fast
>and slow hardener, because 15 mins is to fast and 6 hrs way to slow.
>Being able to mix the hardeners is the great advantage that the MGS system
>has.
>I get a pot life of around 30 mins and is easily tack free in about 6
hours.
>All my temps are around 80-85 F.
>Last night I added some more 340 (slow) to my pump to give me a roughly
>70/30 ratio because I was on a big layup and wanted a slightly longer
>working time, this gave me about a 50 Min pot life and the layup was hard
>this morning (about 12 hours)
>
>I mix a batch about 1/2 gal of 50/50 hardener every couple of months, the
>factory says there is no change at all to the shelf life of the combined
>hardener.
>
>This is from MGS and has been posted before so should be  in the archives.
>
>Mixing ratio of resin: hardener for L335-system is
>100:38 by weight, resp.
>100:45 by volume
>
>Note that these are all related to a temp of 25C (77F)
>
>Hardener 335 and 340 can be mixed together, in order to get a suitable pot
>life. Potlife of 100g mix L335/hardener335 at 25C is approx 15min, 100g
mix
>L335/hardener340 at 25C is more than 5h. Geltime in the laminate is even
>longer. To give you a rough idea of potlifes among different hardener
>mixtures
>
>Hardener335: Hardener340    Processing time
>100                    0                        10-15min
>50                     50                        60-90min
>20                    80                          approx4h
>0                        100                      approx6h
>
>With the above in mind it may be that your temps are a bit low.
>
>MGS web sight www.mgs-online.com
>
>
>Chris Byrne
>
>
>

From: "John Slade" <jslade@adelphia.net>
Subject: COZY: slow expoxy 
Date: Sun, 7 Mar 1999 09:29:28 -0500

I posted my message at 9pm on Saturday. By 9.am sunday morning I had seven
replies all with very useful information. Some had even done tests of their
own MGS epoxy. Incredible!

>Are you using the correct ratio?  Is it by volume or by weight?
I'm using a brand new 45:100 stickystuff epoxy pump. I've been doing really
small tests - less than a "full stoke".
Perhaps a combination of this and the high hot box temp is a problem. I'll
check the ratio by pumping into two cups.

>Try another test and take it to bed with you or somewhere equally as warm
and see how it goes.
I love my plane, Chris - but, she's still very young!

>You should be able to scrape the surface with a nail, and get a scrape with
dusty debris (not a groove in a rubbery mass).
After being in the hot box and the house my test pieces eventually reached
this stage.

>it took 4 days for it to harden  when I first started to use the Mgs
epoxys....I found the best is to mix 50/50  the fast and slow  hardners..
I thought I'd start out slow, but perhaps 100% slow is overdoing it. I'll
try to 50/50 approach.

>They tend to say that below 65 it might not harden at all.
>you need to keep the part at 72 + for the epoxy to cure any time soon
Ah! That I didnt know. I think temperature is is my main problem.
My workshop is a large covered patio which is open on one side.  In a month
or two temperatures here in S. Florida will be in the right range. In the
meantime, I'll work during the 75f daytime.

I'm left with one question. If the layup is done with "warm" epoxy at , say
an ambiant 75f, then left to cure overnight when the temp goes down to, say
60f, will the resultant part be ok in all respects after it eventually
cures?

Thanks to all for the help,
John Slade


From: Militch@aol.com
Date: Sun, 7 Mar 1999 16:00:03 EST
Subject: Re:  COZY: Chap 4 - MGS epoxy won't harden


In a message dated 3/7/99 2:17:56 AM, jslade@adelphia.net wrote:

>I'm using MGS 335 epoxy with the slow hardner.
>I tried a test layup 2 days ago and it's still not hard. Today I tried
>another test and left the remaining epoxy in the cup. 12 hours later the
>layup is still tacky and the epoxy in the cup is still mobile. ie I can
>still move the tongue depresser in it and depress the surface with my
>finger.

I use the 225 and the slow hardener.  Generally I do my layup in the evening
and then do the knife trim the next morning.  That's 10 hours or so and it's
still soft.  It typically takes up to 24 hours to set like a rock in the cup.
That is at temperatures around 70 degrees.  I would be surprised to hear that
2 days is ok.  Sounds like something isn't right. What ratio are you mixing
the parts in?  I use a scale, so have to do it by weight, and its 100:40.

Peter Militch Cozy Mark IV #740 Chapter 4/5

Date: Sun, 07 Mar 1999 16:37:15 -0600
From: David Domeier <david010@earthlink.net>
Subject: Re: COZY: Chap 4 - MGS epoxy won't harden

John,
    re "I tried a test layup 2 days ago and it's still not hard."

    Sounds to me like the resin/hardener ratio is off.  You know the old

clich, this stuff goes together like 2 gears and if they don't match,
it won't cure.  I've had it happen with the original RAF ratio scale
when I somehow moved the balance weight while pouring....

dd




From: "Nat Puffer" <cozy@extremezone.com>
Subject: Re: COZY: Chap 4 - MGS epoxy won't harden
Date: Mon, 8 Mar 1999 13:43:30 -0600

John,
I just finished a several hour layup with 335. I used half slow and half
fast hardner, and it cured right on schedule in about 2.5 to 3 hours.
Regards,
Nat

----------
> From: John Slade <jslade@adelphia.net>
> To: Cozy Builders <cozy_builders@canard.com>
> Subject: COZY: Chap 4 - MGS epoxy won't harden
> Date: Saturday, March 06, 1999 8:13 PM
> 
> I'm using MGS 335 epoxy with the slow hardner.
> I tried a test layup 2 days ago and it's still not hard. Today I tried
> another test and left the remaining epoxy in the cup. 12 hours later the
> layup is still tacky and the epoxy in the cup is still mobile. ie I can
> still move the tongue depresser in it and depress the surface with my
> finger.  Temperature has ranged between 62 and 75 during this period. The
> epoxy is kept in a HOT box. I measured the temp in there and found it was
> 106f. Tomorrow I'm going to try the "fast" hardner and lower the temp in
the
> hot box to about 85.
> 
> Anyone have any suggestions or ideas?
> Is the MGS rep who helped out a week or two ago reading this mail list?
> Anyone have his email address?
> 
> I haven't done a "real" layup yet. If the epoxy doesnt cure the part is
> ruined. - right?
> John Slade (#757)
> 

From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Chap 4 - MGS epoxy won't harden
Date: Tue, 9 Mar 1999 07:43:08 -0600 

John Slade wrote:
> 	
> I'm using MGS 335 epoxy with the slow hardner.
> I tried a test layup 2 days ago and it's still not hard. Today I tried
> another test and left the remaining epoxy in the cup. 12 hours later the
> layup is still tacky and the epoxy in the cup is still mobile. ie I can
> still move the tongue depresser in it and depress the surface with my
> finger.  Temperature has ranged between 62 and 75 during this period. The
> epoxy is kept in a HOT box. I measured the temp in there and found it was
> 106f. Tomorrow I'm going to try the "fast" hardner and lower the temp in
> the
> hot box to about 85.
> 
> Anyone have any suggestions or ideas?
> Is the MGS rep who helped out a week or two ago reading this mail list?
> Anyone have his email address?
> 
> I haven't done a "real" layup yet. If the epoxy doesnt cure the part is
> ruined. - right?
> John Slade (#757)
> 
John: I'm sorry it took so long to respond.    

What you are experiencing is what I feared most when I found out MGS was
being distributed to homebuilders.  Although these are fine resin systems
for which they were formulated for (factory built gliders - motor gliders,
wind mill blades),  they inherently exhibit this peculiarities from time to
time that puzzle the un-knowing.    

Because these products are primarily cycloaliphatic amines and stericly
hindered polyoxyalkyl amines accelerated with copious amounts of unreactive
ingredients, they tend to be sensitive to temperature during cure.   If it
is too cool, (below 70F in my book) they will slow down dramatically of
course, but they can "B-Stage" as well.  This is a physical state where the
resin is neither liquid or cross-linked sufficiently enough to be called a
plastic.  It is "vitrified" and depending on how much is has crosslinked, it
can be a sticky taffy like substance to a brittle friable solid.  Once it
has achieved this vitrified state, it can take a considerable amount of time
for it to continue curing past that vitrified state - if ever.   Sometimes,
it is quite easy to mistakenly identify the brittle friable solid as genuine
cured plastic state.   NOT GOOD.   HOWEVER,  in most cases, with the
addition of heat you can "re-start" the curing process and drive it to
completion.    THIS IS WHY MGS recommends a post cure for their resin
systems. 

If you must use the MGS systems, please be sure your room temperature is at
least 70F.  Especially if your going to use the slow curing agent.     

I have talked about the importance of temperature control many times before.
It is always important  to control the "room temperature" at which ALL your
building materials are stored at prior to their use.   I think it is well
worth the money to buy a window air conditioner for your garage or shop
area.   It reduces the overall sweat factor.

NAT, HUNTER -  sign me up for your forum and dinner.   I have compiled a
nice little presentation on epoxies I think everyone can benefit from.   

Gary Hunter
Shell Chemical Co.
Epoxy Resin Technical Service
EAA Technical Counselor

From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Chap 4 - MGS epoxy won't harden
Date: Tue, 9 Mar 1999 10:20:49 -0600 


> -----Original Message-----
> From:	John Slade [SMTP:jslade@adelphia.net]
> Sent:	Tuesday, March 09, 1999 9:09 AM
> To:	Hunter GA (Gary)  at MSXSCC
> Subject:	Re: COZY: Chap 4 - MGS epoxy won't harden
> 
...they inherently exhibit this peculiarities from time to
> >time that puzzle the un-knowing.
> 
> The above sounds ominous. I realize that you have to be careful what you
> say
> in public. Are you saying between the lines that MGS is not really suited
> for the Cozy?
> 
Not at all.  The MGS systems provide ample performance for the homebuilt.
It is the end-user (you) that it may not be suited for.   If you are not
used to working with epoxies, you can (and have) experience things that will
really confuse you.   

> >If you must use the MGS systems, please be sure your room temperature is
> at
> >least 70F.  Especially if your going to use the slow curing agent.
> 
> I'm building under a covered patio which open on one side. In S. Florida
> temp isnt a problem provide I dont do layups at night during "winter".
> 
> >I think it is well worth the money to buy a window air conditioner for
> your
> garage or shop
> >area.   It reduces the overall sweat factor.
> I'd prefer not to delay my project (and divert finances) to closing in the
> patio.
> 
Granted, summer time temperature conditions are usually favorable in Florida
for curing epoxies.   However, there are many other things to consider.
Humidity, morning dew, sudden afternoon thundershowers with blowing rain.
Ugh....    If I were you, I would spend the money to close it in before you
have to spend the money on rebuilding a part that was ruined inadvertent by
un-expected weather conditions.    
  
> >NAT, HUNTER -  sign me up for your forum and dinner.   I have compiled a
> >nice little presentation on epoxies I think everyone can benefit from.
> 
> I'd like to go to this. WHen and where is it?
> 
We'll let you know with an announcement later.

> Thanks for the input.
> John Slade
> 
> PS - I've changed my hardner slow/fast ratio to 50/50 and am doing all
> layups during the day when temps are 75f and above. Hardning is now to
> spec
> and the MGS is easy to work with.
> 
I think that is a safer gamble than the pure slow.   

Gary Hunter

From: cozy623@juno.com
Date: Thu, 11 Mar 1999 21:16:33 -0700
Subject: Fw: RE: COZY: Chap 4 - MGS epoxy won't harden



--------- Forwarded message ----------
From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
 > Jeb Butler wrote:
> 
> I have had MGS over the winter and I keep my garage nice and
> warm.  No problems so far.  My question is about heat.  I live in PHX. 
> Is there a point where it is too hot and I should not work with epoxy?
> 
I guess 105-110F in the shade is not to unrealistic for PHX.   You should
stop working with the epoxy when you pass out from heat exhaustion.  :-) 

In all seriousness, there comes a time when the viscosity becomes too low
for laminating vertical surfaces.  "Drain-out" can occur as a result -
leaving resin starved laminates.        
>  
> Is MGS different in how it reacts to heat also?   
> 
Yes, it won't pass out from heat exhaustion like you - ha ha.  

The MGS resin system likes heat.   It will simply cure faster.   The rate
of
reaction doubles every 10 degrees Celsius.   So a 2 hr. gel time at 25C
(77F) will become 1 hr at 35C (95F) and 30 minutes at 45C (113F).    

> I had thought that the long cure time of the MGS would be very handy
when
> the heat comes back
> and accelerates the cure to mach speed.  
> 
You are absolutely correct.  You can probably get away with the slow
curing
agent in the summer and a 50/50 blend of slow and fast in the winter.   

Gary Hunter


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From: "Will Chorley" <anneandwill@worldnet.att.net>
Subject: COZY: MGS Epoxy - Can set up too fast!!
Date: Tue, 16 Mar 1999 21:20:30 -0600

Reading the recent correspondence on MGS NOT setting I thought my recent
(this evening) experience may be of interest.  I just had a "small job" to
do - you know one of those that should take 10-15 minutes but ends up taking
half an hour - and decided to mix a couple of ounces of MGS 285 with the
fast hardener.  I had my shop at about 80 degrees, but the epoxy had been
out on my bench before I turned up the heat and was probably closer to 70
degrees when I mixed it.  After about 15 mins, I had used probably half the
mix and it was beginning to get a little warm - actually this was good as
the viscosity had become really low - and then, almost without warning it
turned to jelly and then, within seconds, crackled and popped and smoked and
set up hard - with my brush stuck firmly in it!!  I have only recently
started using this stuff - I've been a Safty-poxy user up to my last batch
and have never had an exotherm with the Safety-poxy.  I was surprised at the
rapidity of the reaction, particularly as there was less than 1/4 inch in
the bottom of the pot.  I find that with the slow hardener I get about 45
mins working life at 80 degrees before it starts getting a bit jelly like
and doesn't wet out very well - this is about the same working time as I got
with the  Safty-poxy.

I do have one other problem with the MGS product - it seems to "foam" easily
when wetting out, rather like the Epolite 2427 which I tried for a short
while.  Any thoughts on reducing/avoiding this problem, or similar
experience to share?

Will Chorley



From: "John Slade" <jslade@adelphia.net>
Subject: Re: COZY: MGS Epoxy - Can set up too fast!!
Date: Wed, 17 Mar 1999 09:33:03 -0500

Will,
>then, almost without warning it turned to jelly
I had a similar experience with my MGS last night.
I keep my epoxy in a hot box (90 or so). The workroom temp was about 78 and
I'm using 50% fast / 50% slow.
After about 30 mins I needed some epoxy to wet up a dry area and found I was
painting jelly. I discarded the ply of bid, cut another piece and mixed new
epoxy.  This wasnt a dramaric exotherm, just jelly way before I expected it.
First time it happened.

>it seems to "foam" easily when wetting out
I also get some foam if I stipple a lot, but it paints away with a gentle
brush stroke.

Nat said in a newsletter "If I were building another plane I'd use MGS". I
spoke with him about it and he confirmed that he'd used it and liked it so I
took his advise. MSG is the only epoxy I've used, so I can't offer a
comparison. I like the stuff and I'm getting used to how it works. I'm
getting good results (confirmed by EAA tech consultant) and my parts are
light.
John Slade (Cozy #757)
Moving into Chap 5....




From: Epplin John A <EpplinJohnA@jdcorp.deere.com>
Subject: RE: COZY: MGS Epoxy - Can set up too fast!!
Date: Wed, 17 Mar 1999 10:47:15 -0600

My experience has been very similar to what I have seen posted.  I might add
a couple of points.  I prefer using a squeegee rather than a brush if
possible.  I think this reduces the foaming somewhat.  Obviously it is not
feasible to use the squeegee to apply the resin to vertical surfaces.  Also,
it seems the fast hardener is too fast for anything except very small jobs
if the temp is above 75.  I found a mix of 50-50 to be a good general
purpose ratio.  I used the slow straight for large lay-ups such as the
strake outer skins where there is multiple layers over large surfaces.  Get
your glass prepared so as not to spend much time between layers.  If you
have help you may be able to take it right off the roll onto the surface,
this works best IMHO.  Otherwise have it cut to size and rolled neatly so
you can get it in place with a minimum of fiddling around.

My experience has been that the two hardeners full cure at about the same
time, that is about 24 hours before you want to do any sanding at 75 to 80
deg. F.  The fast hardener may be sanded 8 hours after mix in 90+ deg
conditions usually.

I have used 2427 and Aeropoxy also and at this stage I agree 100% with Nat,
I would use the MGS for all laminating.  I keep both the resin and hardener
at 100 deg F in a temperature controlled box that I would recommend you
fabricate somehow.  Grainger sells a couple of thermostats that are capable
of 115 volt operation at several amps, you can use light bulbs or strip
heaters or whatever you can come up with, I use some large power resistors
that I happened to have around.  A small fan is needed, otherwise the top of
your box will be hot and the material sitting on the bottom will not be
heated as desired.  Leave the fan run continuously.  I found a small 115
volt muffin fan at Radio 
Shack that has run continuously for over three years now.  It rattles a bit
but keeps on running.  I have it fused for 1 amp, just in case.  My box is a
compartment of a utility cabinet purchased from Loews, lined with fiberglass
ceiling tile pieces with a foam gasket around the door.

Hope this helps someone.

John Epplin   Mk4  #467, almost done with laminating epoxy, going to filler
stuff next.

From: "Steven Willhoite" <swillhoite@csi.com>
Subject: RE: COZY: MGS Epoxy
Date: Wed, 17 Mar 1999 12:57:17 -0700

Just wanted to put in my two cents that I too have turned into a fan of MGS
L335 epoxy.  I built my Mark IV up through chapter 13 using Safe-T-Poxy and
am now using MGS.  The smell of Safe-T-Poxy would spread from my garage
through the house every day I did layups.  It was especially bad in the
winter.

My family hardly knows I am doing layups with the MGS.  I also find the
viscosity of the MGS to be slightly lower which makes it much easier to wet
out the cloth.  I find a 50/50 mixture of the slow/fast hardener to be about
right.

I do get some crystallization in the hardener nozzle of my Sticky Stuff
dispenser when I don't use it for a few weeks, but it is easily cleaned out
prior to pumping a fresh batch.  I always keep my epoxy pump closet
thermostatically controlled to 80 degrees F using a light bulb for heat.

Steven Willhoite
Cozy Mark IV #006

P.S. You can get more info, including mixing ratios and curing times at...

L285 spec. sheet: http://www.mgs-online.com/pdf/foreign/01mgs037.pdf
L335 spec. sheet http://www.mgs-online.com/pdf/foreign/01mgs061.pdf



From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: COZY: More epoxy questions - Fuel Resistance
Date: Fri, 19 Mar 1999 07:28:47 -0600

Ric Lee on Canard Aviators wrote:

Gary, have some epoxies been found that are better suited for use in
making fuel tanks than others?  I believe I read about some epoxy
flaking off in fuel and causing a Cozy to crash.

All the suppliers claim their "structural resins" are suitable for fuel
containment.  And, they are - IF - the builder knows how to go about it and
does everything correctly.   I have always been adamant about "post curing"
epoxies,  especially the fuel tank.   You can't buy cheaper insurance.

Safe-T-Poxy I or now EZ-Poxy 87 is probably by far the best in this
category, with or without a post cure.   Chemical resistance is one of the
prime attributes of epoxies beyond homebuilding airplanes.  They are used
for building fiberglass chemical storage tanks and piping and for lining of
steel tanks to prevent corrosion.   In that industry the curing agent "type"
governs the degree of chemical resistance.    Aromatic amines are by far the
best know curing agent type for overall  chemical resistance - particularly
in fuels, solvents and strong acids.   EZ-Poxy 87 is the only aromatic amine
curing agent available to the homebuilt world.  

Next in line are "aliphatic amines".   The original RAES & RAEF were
"modified" aliphatic amines.  However, according to my tests the RAES
without a post cure was absolutely no good for fuel and marginal with.  But,
the RAEF without a post cure was marginal and did just fine with a post
cure.  Thus, the original Vari-Eze plans mandated RAEF for the fuel tanks.


Next in line are "cycloaliphatic" amines.   Aeropoxy,  MGS, Proset, and
EZ-Poxy 83 & 84 are "blends of modified aliphatic and cycloaliphatic amine
adducts".   Modified - because the straight stuff has bad cure behavior.
Some modifications work out better than others.   A prime example is the
Aeropoxy's sensitivity to temperature and moisture.   I call these "quirky
cure characteristics".   However, even the "quirkiest" of these curing
agents will resist fuel - IF - they are properly applied and fully post
cured.   

DO NOT simply brush the resin on the inside surface of the already cured
fuel tank and expect it to cure like a 2 or 4 ply lay-up.  This is were the
screen plugging flakes of epoxy come from.    

Your original layups for all the inside tank components should be "wet" so
to be certain there are no dry spots, pinholes or voids.  This is no place
to be too concerned about weight.  Even the BID tapes in the corners should
be nice and wet.   Peel ply only were secondary bonds will be needed.   For
those of you than like the smooth surface of peel plying - add an extra
final ply of a fine weave light weight fiberglass deck cloth.  It will give
you a similar smooth surface without introducing or hiding voids.   Warm
shop temperatures and low humidity will reduce the curing agents "quirk"
factor. 

There are many ways to obtain a post cure on the tank.   Before the tops are
put on, you can use heat lamps to cure the inside surfaces.   You can
pre-post cure the inside surface of the top too.   After the top is bonded
in place you can post cure these bonds by heating the exterior surface with
heat lamps.  The heat will work its way to the bonds.

OR, after the top of the tank is bonded on,  you can circulate warm air
through the tank for several hours.  I did this with the outlet end of my
vacuum cleaner inserted in to the fuel cap opening.   About 140F is
sufficient.

RULE OF THUMB - If you can hold your hand on the surface to the count of 10
- the temperature is 140F or below.   

Hope this is helps.

Gary Hunter
EAA Technical Counselor
Vari-Eze  N235GH

  

From: Chm12345@aol.com
Date: Sun, 21 Mar 1999 21:30:08 EST
Subject: COZY: Experience w/ MGS epoxy

I'd like to share my experience with MGS epoxy.

I'm currently using L285 and I'm extremelly happy with it. I initially used
the H285 hardener but discontinued that practice since, here in Florida, the
use of this hardener almost guaranties an exotherm reaction unless the
quantities are very small (and I usually mix very small quantities) or the
temperature is low. I now use H287 which is the slow hardener and it works
great. I haven't experienced the problem another Cozy builder reported with
the product not hardening but the temperature never really gets too low. I do
inspect the contents of the pump for crystalization every time I use it and
verify the ratio and document the results every month or every time I'm going
to perform a critical layup (I'm using the AR100 pump).

The only problem I experienced with the MGS hardener is that it tends to
crystalize with relative ease when left on the pump's plastic container for an
extended period of time. The problem is that this crystals will not return to
the normal product after heating it. MGS explained to me that this is caused
by the hardener reacting with CO2 and the crystals are urea crystals which
will not revert to the original hardener after heating. After sealing the
container's lid very well with the use of tape the problem re-occured. I
noticed that the hardener in the original metal continer never cristalized so
I drilled a hole on the bottom of the original hardener metal container and
installed on the pump (The resin is OK in the plastic container). No crystals
noticed again. Lastly, I always cap the nozzels of the pump with a bit of
masking tape which I wrap arround the nozzle, letting some extend beyond the
end of the tip, and I then pinch the end of the little tube that forms to seal
the nozzles. The hardener does tend to crystalize very easely in this area and
by keeping it away from the air it doesn't do it anymore.

The reason I like MGS so much is that it is not only a very nice product but
is is used on certified aircraft such as the Diamond Katana and other German
gliders imported in the US (which I had the opportunity to own and can attest
to the quality of this resins). By being certified (by german authorities) it
gives me the assurance that the product will perform if used as specified. No
risk of changed formulation or old components. This to me is worth any extra
money the MGS epoxy cost.

Chris

From: Lee810@aol.com
Date: Mon, 22 Mar 1999 00:24:18 EST
Subject: Re: COZY: Experience w/ MGS epoxy

In a message dated 3/21/99 7:34:54 PM Mountain Standard Time, Chm12345@aol.com
writes:

> Lastly, I always cap the nozzels of the pump with a bit of
>  masking tape which I wrap arround the nozzle, letting some extend beyond
the
>  end of the tip, and I then pinch the end of the little tube that forms to 
> seal the nozzles. The hardener does tend to crystalize very easely in this
area 
> and  by keeping it away from the air it doesn't do it anymore.

I use the finger of a latex glove held on with a rubber band to prevent
crystallization of the MGS epoxy on my hardener nozzle.  It always seems that
I have about ten of those things available after a layup.

Lee Devlin
http://members.aol.com/lee810

Date: Sun, 11 Apr 1999 12:33:09 -0500
From: "Joseph H. Hart" <jodyhart@home.com>
Subject: COZY: Yet Another Epoxy Question

Fellow Builders:

	I haven't worked on the project in few weeks and am ready to get back
to it.  One of the reasons (other than work!) for my hiatus is that the
last gallon of MGS 285 resin that I purchased, coupled with the recent
discussions on this forum, caused me some concern.  I noticed when my
old bottle of resin (with about 3/4" of resin in it) and my new bottle
were next to one another, the new bottle does not seem as transparent.
However, I don't really think that the new bottle is any less
transparent than my earlier bottles appeared when I got them.  Because
of the recent discussions and because the bottle say "USE ONLY
COMPLETELY TRANSPARENT RESIN", I started to question the condition of
the new resin.  Frankly, but for the discussions, I don't think that I
ever would have questioned a thing.  Anyway, I e-mailed MGS but never
received a response.  Thus, I turn to you (Gary, are you out there?).  

	The resin is not what I would call "cloudy" as it is homogenous in the
degree to which it is transparent.  It looks more like tap water with a
lot of minerals in it.  I heated it up in a double boiler to about 155 -
160 degrees F for approx. 2 - 3 hours, shaking it up during the
process.  There was no change but for the labels coming off.

	What do you think?  Is it OK to use?  I've got one side glassed and one
to go.  I'd really like to get the other side done.

	Thanks in advance for you advice.
-- 
Jody Hart
Cozy Mark IV plans 648, Chap. 7, progress at:
http://members.home.net/jodyhart/index.html

From: "Chris Byrne" <jcbyrne@ozemail.com.au>
Subject: COZY: MGS Epoxy
Date: Mon, 12 Apr 1999 14:22:56 +1000

Builders

The email from Jody Hart jogged my memory.

Again this is a bit long winded, but the archives will now contain all of
the info I have recieved from MGS on their epoxies.

About two months ago I had some problems with the crystalization of the L335
resin, which was easily fixed by warming the resin, however I had been using
this cloudy resin for a good month or so and some of it was almost sludge
like in the very bottom of the epoxy pump.
I was concerned (so was MGS) about the strength of these layups, so I sent
some offcuts to MGS to be tested at their suggestion.
They were actually very quick in their response, its me who has been a bit
slack in posting the results.

Below is a copy of all the info I recieved from Johannes Meunier about my
samples.

"The way the crystallisation effects the epoxy resin.

Both, resin and hardener are a formulation of different ingrediences. These
different substances have different properties, one of them is a different
affinity for crystallisation. Each of the ingrediences also have different
mixing ratios. What may happen at a crystallisation is, that only a part of
one component of the composition gets solid. If you take the remaining
material,
the mixing ratio has changed and you may mix resin and hardener in a
non-optimum
mixing ratio. This affects the amount of cross linking in the molecular
structure, because you either have too much resin or too much hardener. This
is measurable by determination of the Glass Transition Temperature. Each of
our
resin systems has a certain range of a maximum possible Tg. By comparing the
maximum Tg of your sample to the "normal" value, I can tell whether the
material is o.k. or not.

The effect of crystallisation on the mixing ratio of the resin is way lower
than on the hardeners. So I would not worry at this time about the quality
of the
laminates. I will, however measure the samples youre sending over and let
you know about the results".

The results of the four samples that I sent all indicated the TG to be
within 2C of the
maximum that MGS expect from the L335 system (80-85C).
They would have been concerned if they were down to (70-75C)
The samples showed a TG of around 51-55C after the first run (indicates the
room temp TG) and 82-84C after the rapid postcure.

"We performed two runs on the samples. In the first run, the sample gets
heated up to 200-250C. After that run, we can determine the Tg as it
was when we got the sample. After that run, we assume, that the sample
is completely cured (some kind of a very fast post curing cycle).
The secon run gives us the info of the maximum Tg, we get with the
sample. As I wrote you, if a sample is not mixed properly, or the mixing
ratio would be wrong for whatever reason (such as chrystallisation), it
would be significantly lower".

The following is some general statements from Johannes Meuiner of MGS that
he is happy to have published. His direct e-mail address is at the end.

"I would appreciate it, if you could give the advise of heating up resin /
hardener when they are crystallised. This may help homebuilders to achive a
better quality and learn more about the specific working properties of these
products.
However, there are some resins that come out cloudy, due to some additives
in them, for example our L418 ( a resin system for higher temperature
applications >100C). No matter how much you heat that up, it will stay
cloudy, because it IS cloudy - however, this is not crystallisation.

For the L335  and L285 which is mostly used in the homebuilder scene, it is
true, that cloudiness is a signal for crystallisation.

I would not state in the advice, that even when the products are
crystallised, they still have good properties, because they may not, and
some people may think they dont need to worry if it crystallises. And I
want them to worry.
We are building airplanes and I want our materials to be worked in the way
the are
supposed to be, to make sure there is ALWAYS  the quality an airplane
requires.
We were lucky in your case, because it was only a small amount of
crystallisation. If this becomes significantly more, or worse, the
crystallisation occurs in the hardener instead of the resin, the effect on
the properties of the material may be significantly higher.
Id rather see the advise to be given, that if crystallised resins /
hardeners have been worked, they should be tested for their quality by a
potential Tg
determination.

It is a normal thing that these material crystallise and most people are not
aware of this. If we can do some education in a way that this may be a
problem and people should be aware of it, this would be the best we can do.

It those people have questions, Ill try to answer them as I can, and maybe
you can insert a link to our website and my email adress. As you know,
airplanes
and flying is my world too, and I am glad that it is such a small world
where
people work together with the same intentions. Sometimes this collides with
the job
I have to do, but you can consider it as a contribution to my own flying...

If I can do anything more, let me know.

Johannes""""


Meunier@mgs-online.com

Hope this helps.

Chris Byrne



From: JERSKIP@aol.com
Date: Wed, 21 Apr 1999 13:23:13 EDT
Subject: COZY: (no subject)

Being a brand new builder,(plans #768), I'm trying to select resin type to 
use. I've seen many good comments re: MGS 335, but not many comments about 
the 285. I live in Florida, so cold is not a problem, and I'm considering 
post curing the 285 system so I'd have a few more options on colors. Comments?

Jerry Schneider

Date: Wed, 21 Apr 1999 11:57:08 -0700
Subject: COZY: Re: Epoxy selection
From: "Thomas Kennedy" <tmkpida@pacbell.net>


----------
From: JERSKIP@aol.com
To: cozy_builders@canard.com
Subject: COZY: (no subject)
Date: Wed, Apr 21, 1999, 10:23 AM

In reply to...
Being a brand new builder,(plans #768), I'm trying to select resin type to 
use. I've seen many good comments re: MGS 335....

My impression is that the BAD comments outweigh the good. Post curing seems
involved. Seen many non-hardening stories. The Safe-t poxy is approved and
has worked well for me in the Southern California climate. The stuff stinks
(literally) but not that bad and certainly not enough for any neighbor in
close quarters to complain about.

Due to lack or bond strength after initial set I do not recommend the 2427.
I have a canard with this stuff that looks good, but is causing me angst.

Use a hair dryer to help with layups particularly the UNI ones.
Build a heat box to keep epoxy warm.
Keep the dispenser clean.

Thomas Kennedy
#248
Spar done, wings started (finally)



From: DougSheph@aol.com
Date: Wed, 21 Apr 1999 16:01:29 EDT
Subject: Re: COZY: L285 epoxy system

Jerry Schneider wrote:
>>...not many comments about the MGS 285...

I'm a little bit ahead of you (one fuselage side completed), and I've used 
the L285 system exclusively.  So far I'm delighted with it.  It has 
essentially no smell, it cures beautifully in San Diego-area weather, and the 
viscosity makes it very easy to work with.  I am told it's not affected much 
by moisture, either, although that's not much of an issue out here in the 
desert.  It's workable as low as 70 degrees, and I'm assured (by Johannes at 
MGS) that it will cure fully at that temperature, but cure is much faster and 
it's much easier to work with at 80 degrees.  I most often use a 50:50 
mixture of the fast and slow hardeners (try that with the other systems!), 
which gives decent pot life at 70-80 degrees and will cure in 3-6 hours at 
those temperatures.  On those dog days, I mix a little more of the slow 
hardener into my epoxy pump, keeping rough track of the extra and how much 
I've used so I can get it back down to 50:50 when the weather cools off again.

I suspect the 'non-curing' problem seen by some is caused by crystallization, 
which every epoxy system is susceptible to, to one degree or another.  My 
suggestion there is to keep the epoxy (including full cans) ovenized at 90 
degrees or so and inspect for cloudiness before each use.  Use the documented 
procedure if you see any sign of crystallization (I never have).  Also, and 
perhaps most importantly, don't let the project sit idle for weeks.  I've 
found that if I work at least a little on the project every day, the epoxy 
stays fresh, the pump stays limber, and I stay excited about the project.

Doug Shepherd

From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Epoxy brand compatibility
Date: Tue, 27 Apr 1999 10:27:22 -0500

John Epplin Mk4 #467  wrote:

> Need some expert knowledge.
> 
> I made my wings and winglets from Aeropoxy PR3660/2032 epoxy.  Soon will
> come the time to join these parts.  I have been using the MGS 285 for some
> time now and wonder if it will make any difference using MGS for the
> attachment over the Aeropoxy.  The Aeropoxy has been peel-plied at all the
> mating surfaces.  I am quite sure they will stick together, just wonder if
> there are any known problems switching systems.
> 
The two resin systems should be fully compatible. 

Surface preparation is still the most important thing for obtaining good
secondary bonds.  If the peel ply has been in place right up to the point of
laminating the next layer, very little to none is needed.  However, if you
removed the peel ply many days, weeks or months ago, you should abrade the
surface completely with at least 80-100 grit sand paper.

Gary Hunter
EAA Technical Counselor
Crew Chief - The EXXON Flyin' Tiger

Date: Tue, 27 Apr 1999 16:40:32 -0400
From: Jeff Russell <JRaero@gte.net>
Subject: Re: COZY: Epoxy brand compatibility

Epplin John A wrote:

> Need some expert knowledge.
>
> I made my wings and winglets from Aeropoxy PR3660/2032 epoxy.  Soon will
> come the time to join these parts.  I have been using the MGS 285 for some
> time now and wonder if it will make any difference using MGS for the
> attachment over the Aeropoxy.

Don't forget that you need to post cure the MGS system.
--
Jeff Russell/AeroCad Inc.                    E-mail:   Jeff@aerocad.com
2954 Curtis King Blvd.  Ft. Pierce, FL. 34946
Shop# 561-460-8020 7:00am to 3:30pm  Home# 561-344-6200
Website:   http://www.Aerocad.com
Composite workshop info:   http://www.Sportair.com


From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Epoxy brand compatibility
Date: Fri, 30 Apr 1999 09:34:02 -0500

Jeff Russell wrote:

> Jeff,
> >Don't forget that you need to post cure the MGS system.
> 
John replied:

> Are you suggesting that MGS requires a post cure while other epoxy systems
> don't ? If so, what do you base this on ?
> Regards,
> John Slade Cozy Mk IV #757, N386JS
> 
Jeff, Hope you don't mind me chiming in here....

John - 

This is based upon the manufacturer's product technical bulletins.   MGS
themselves prescribe a post cure for their products.   

The MGS systems were specifically formulated for the production of
commercial sailplanes and motorgliders in which the factory production
schedule utilizes oven post curing as a norm.

They were not formulated for applications that require a  Room Temperature
(RT) cure alone.   

Incidentally, a friend of mine was telling me he found the internet site for
the European equivalent of our NTSB and was horrified to see that about 10%
of the aviation accident reports in their system involved sailplanes and
motorgliders having major structural failures.  All them aerobatic certified
aircraft.  There is no way to tell how many, if any of these aircraft were
built from MGS systems.   But, given the location and aircraft type,  I
would say the probability is pretty high that some of them were.    Do not
misinterpret what I am saying.  There are no indications that MGS systems
are inferior in any way.   The structural failures in these aircraft could
be simply overstress or design related, and the fact they may have been
built from MGS resin a pure coincidence.   

However, considering the above, the requirement of a post cure, and given
the flawless tract record of the Safe-T-Poxy system (now EZ-Poxy) I am
curious as to why anyone would even consider using anything else.   

Gary Hunter
EAA Technical Counselor
Shell Epoxy Resins Technical Service

From: "Nat Puffer" <cozy@extremezone.com>
Subject: COZY: Epoxies-post cure
Date: Fri, 30 Apr 1999 11:11:35 -0500

Dear Cozy Builders,
It so happens that I have been collecting data on all of the epoxies which
have been approved for wet layups and room temperature cure, and there is
not one of them which reaches full cure and full properties without post
curing. The most important temperature related property is heat deformation
temperature, at which temperature the epoxy begins to soften and begins to
lose mechanical properties. Here is the data I have for heat deformation
temperature vs cure temperature in degrees F.:

Epoxy	       R.T.Cure	Elevated Post cure
RAE		120		151
Safe-t-Poxy	118		171
2427		117		162
EZ Poxy	125		158-170
PTM&W	---		202
MGS 335	130		185
MGS 285	150		240

I can tell you that there were many (including mine) Variezes and Long EZs
made with RAE epoxy without post curing (in the technical sense) and there
have been no structural failures attributed to lack of post curing. As a
matter of fact, my Varieze, after it changed hands, sat outside on the ramp
in Chandler AZ for 2 years at least in the hot Arizona sun in ambient
temperatures which have been known to reach 122 deg. F, and the airplane
did not melt nor did the wings droop. One of the reasons might be that the
resin continues to post cure as it sits at higher temperatures, and the
heat deformation temperature always increases with cure so that it is 40 to
50 degrees above the temperature at which it has been soaked. I have built
and flown 3 Cozys which were built with RAE and not post cured, and none of
them have melted nor fallen apart. As you can see from the above, the MGS
resins have a higher heat deformation temperature after both a room
temperature and elevated temperature cure (with the possible exception of
PTM&W). It is my opinion, based upon my investigation and experience that
the MGS resins are superior to what I have used in the past and would be my
first choice  if I were building another airplane today.
When it comes to structural failures of sailplanes in Europe, one would
have to determine what loads the structure was designed for, and what loads
it was subjected to, and even then it would be hard to pin a failure on the
epoxy used. The first thing to suspect is not enough glass. Maybe one
reason RAE and Safe-t-Poxy have such a good record is that the Long EZ was
designed for 12 to 18 gs, which even the human body could not withstand
without failing. As long as you remember to add the hardner, and add the
right amount, I don't think you need to worry about having a structural
failure because you didn't post cure the epoxy. But as one person aptly put
it, nothing that an engineer has ever designed cannot be made to fail
(double negative intended). 
Best regards,
Nat
 				

Date: Fri, 30 Apr 1999 17:44:18 -0700
From: marcna <marcna@concentric.net>
Subject: Re: COZY: 2427 Revisited

My complete airframe, canard, main spar, and wing was completed with 2427.
Now that I am two months away from doing my first flight I should redo my
whole project, to late to turn back now.

Marc Parmelee

Michael Link wrote:

>
>
> Dear Builders,
>
> I have only been a subscriber to this group for a short while, so I
> don't
> know what had previously been said about 2427 epoxy resin. I know that
> the
> Cozy newsletter discussed problems that some people had experienced and
> that the product had been withdrawn from the approved epoxys. I used
> 2427 in the final construction phase for non-structural applications
> such as armrests, wheelpants, etc., and experienced no problems using
> the material. The 2427 behaved and looked similar to the RAE epoxy of
> which most of my plane is constructed .
>
> I recently caught my left wheelpant on a small "curb" when pushing the
> plane into the hangar. When I surveyed the damage, I was surprised to
> find that several layups had delaminated. The 2 inch BID strip that held
> the wheelpant halves together, as well as the lip that holds the
> nutplates for the "pie pan" portion of the assembly had pulled away from
> the pant.  Did I thoroughly prepare the surface with 80 grit paper? Did
> I peel ply the BID tapes to avoid a stress riser? Did I thoroughly
> inspect the assembly for air bubbles, etc.  Is the Pope Catholic?
>
> I was (negatively) impressed with how easily the laminations could be
> seperated.It was not unlike tugging on a zipper. I don't want to be an
> alarmist, but if you have anything critical in your airplane made with
> 2427,
> you had better consider removing it . The layups that I did were not
> done in a high humidity environment and looked great until stressed. In
> my opinion, it is better to make a painfull decision now, than to risk a
> disaster later.
>
> Regards,
> Michael Link    COZY MK-IV    N-171ML

Date: Fri, 30 Apr 1999 21:55:46 -0400 (EDT)
From: "George A. Graham" <ca266@freenet.buffalo.edu>
Subject: Re: COZY: 2427 Revisited

On Fri, 30 Apr 1999, marcna wrote:

> My complete airframe, canard, main spar, and wing was completed with 2427.
> Now that I am two months away from doing my first flight I should redo my
> whole project, to late to turn back now.


I also used 2427, and I have tested it inflight in the most severe
turbulence, where I was afraid the wings might come off.  So far
so good.  My one really hard landing spread the main gear hoop out
so far as to scrape the brake calipers on the runway (the main gear hoop
is one that I made also with 2427).  

Of course I wonder why there are problems, but I am certain that
mine is solid, even the fuel strakes are without trash or leaks.
  


George Graham
RX-7 Powered Graham-EZ, N4449E
Homepage <http://freenet.buffalo.edu/~ca266>

From: DougSheph@aol.com
Date: Fri, 30 Apr 1999 23:59:05 EDT
Subject: Re: COZY: 2427 Revisited

As far as the epoxy issue goes, I would definitely side with Nat and the 
others who maintain that the 2427 problems (after FULL CURE) are so minimal 
that they're not worth worrying about much.  On the other hand, I have to 
admit that I probably would worry about it a bit, at least until the airframe 
had proven its ruggedness.  What would I do if I was in that situation?  Do 
what Johannes suggested, rent an auto paint shop's curing booth for an 
overnight post cure of the whole airframe.  Then I'd fly it, secure in the 
knowledge that a) the materials in the plane are guaranteed to be fully cured 
and at the peak of their performance, and b) as Nat pointed out, NO accidents 
of this family of aircraft have been shown to be related to epoxy failures 
anyhow.

Date: Sat, 01 May 1999 17:46:46 -0500
From: Kent Ashton <kjashton@vnet.net>
Subject: Re: COZY: 2427 Revisited

FWIW:  I skinned a wing with 2427.  I did the work in my basement so
the environment was probably cooler and slightly higher humidity than
outside conditions.  Later, I had a spot on the wing delaminate when I
removed some bondo and I started to pick at it.  I found I could strip
off all the layers of wing skin, except the bottom layer next to the
foam, by pulling up a 1-2" wide strip and ripping it off.
	I ended up ripping off the skin and reglassing with RAE.  All my other
work was done with RAE or EZ-Poxy and I haven't seen that kind of weak
peel strengh with those two.
		
Michael Link wrote:
> 
> I recently caught my left wheelpant on a small "curb" when pushing the
> plane into the hangar. When I surveyed the damage, I was surprised to
> find that several layups had delaminated. The 2 inch BID strip that held
> the wheelpant halves together, as well as the lip that holds the
> nutplates for the "pie pan" portion of the assembly had pulled away from
> the pant.


From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: COZY: Apology
Date: Fri, 7 May 1999 14:32:58 -0500 

I owe you COZY listers an apology.  I probably confused many of you by
accidentally referring to 2427 as an Aeropoxy product rather than Hexcel and
for that I am sorry.  It was an honest mistake.  You guys have it easy with
7 or 8 different products to keep track of.   In my job at Shell Chemical
Company I have to keep track of 400 of my own products plus my competitors
products that go into making the 8 or so products you guys have to select
from.   Talk about confusing.

Fact of the matter is, both the early version of Aeropoxy and the Hexcel
2427 had problems associated with it's chemical make-up that neither
producer anticipated because it was not field tested in all conditions
before release.  Now, Hexcel 2427 is gone and reformulated Aeropoxy products
are as good as the others.

In recent years, we have all been introduced to a  host of "new" resins.
They aren't new at all.  They are simply different blends of old technology
that has been around since the 1940's.  The "formulators" that produce these
new resins, all believe they have a better mouse trap.   After all, it is
free enterprise system here in the USA.  Competition is good for the
consumer, it tends to drive prices down - but I don't think we have seen
that here.  While all these formulators are reputable outfits doing their
very best to provide a good product, their developments are all conducted
under laboratory environments that do not always represent the real world.
My goal is to help you understand what can go wrong, why it happens, how you
can prevent it, and what to do if it happens.  If I am succeeding or failing
at my goal, I would appreciate feed back to that effect.    

Below are my TOP TWO TIPS for countering potential problems with ANY Resin
System:

Shop Temperature Control - This is cheap insurance.  A $400 window air
conditioner is the single best investment you can make for the benefit of
your project.  The problems most often encountered with epoxy resins occur
when field conditions don't match the lab conditions in which the resin
system was formulated by the supplier. It only makes sense that if you match
those lab conditions you can expect it to perform as the supplier intended
it to.  Laboratory temperature conditions 25C (77F) are perfect for storing
the resins, curing agents, and the various reinforcements.  A constant
temperature insures consistent resin properties - constant viscosity gives
consistent wet out and resin to glass ratios.  Since these conditions are
very hospitable for the builder too, it is more likely you will work on the
project more often resulting in faster completion times.

Post-Curing.  -  Nat is absolutely correct about the EZ airframe design
family.  The differences in HDT or Tg between the various resins systems,
with or without a post cure is not going to make a flip.  The airframes are
so over-designed, they aren't going to melt into the tarmac in the hot
Arizona sun.  And, yes, the resin will post cure itself over time as it is
exposed to more and more heat over it's life span.  And there is a pile on
non-post cured airplanes flying out there today without a hitch.
Nevertheless, post curing helps to make up for those nights when the shop
temperature dropped too much,  and the lay-up was still sticky in the
morning.  Or, "It sure was hard sanding in that tight little corner, I hope
the resin sticks good".   Or,  "I wonder when that ratio pump started
messing up - I hope this layup is OK."  And, "Will autogas or the next
generation Avgas attack my fuel tanks ?"    Think about it.  It is simply
more cheap insurance, peace of mind when you need it most, and added value
for when it comes time to sell it.  

Once again  - my apology for getting too technical and confusing you with an
information overload.   

Have a nice weekend.

Gary Hunter
EAA Technical Counselor
Shell Technical Service


From: "Will Chorley" <anneandwill@worldnet.att.net>
Subject: COZY: MSG Epoxy and Pumps
Date: Sun, 9 May 1999 19:41:05 -0500

Having run through approx.. 2/3 of a gallon of MGS epoxy weighing it out, I
have been thinking of converting my old pump to pump this stuff as I have
come to like working with it.  I have had no bad batches with the weighing
method, but the pump is certainly much easier, less messy, and, I suspect,
more accurate for small amounts.  I've noticed much correspondence on the
use of pumps with the MGS epoxy, and the major problem reported seems to be
that of crystallization of the hardener.  One correspondent changed from the
poly containers to using the metal cans that the hardener comes in to try to
avoid the crystallization problem, has anyone else tried this?  I keep the
pump and my epoxies in a temp controlled cupboard and have been keeping the
epoxy and hardener at 80 degrees and have had no trouble with the resin or
hardener in the can.
Thanks, as always, for any help,

Will

From: "John Slade" <rjslade@bellsouth.net>
Subject: Re: COZY: MSG Epoxy and Pumps
Date: Sun, 9 May 1999 21:30:49 -0400

Will,
My MSG is in the standard plastic pump containers in a hot box. I
occasionally get a bit of crystallization of hardner on the output nozzel
which I scrape off with an old drill bit.  Other than that I have had no
problems at all with the standard pump.
John Slade

From: "cliffordfamily" <cliffordfamily@provide.net>
Subject: Re: COZY: MSG Epoxy and Pumps
Date: Mon, 10 May 1999 14:18:14 -0400

We keep our MSG in the plastic pump containers in a heated cabinet. We also
cap the ends of the spouts at the end of the day.  We are well into chapters
6 and seven on two Cozy MK IV,s and have used the MSG resin and hardeners
with the pump since the start.. We have only had a problem at the beginning
before capping off the spouts. None since.  Dave and Mike.

From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: PTM&W Appearance
Date: Mon, 10 May 1999 08:18:23 -0500

Will wrote:

> I just got some PTM&W from Wicks. I am switching to this from RAE, so I
> have
> not ever used it before. The resin seems cloudy to me - I can not see the
> bottom of the can (1 gallon) by shinning a light in from the top. I know
> what crystals look like because I had an RAE resin can get crystallized
> once. The PTM&W doesn't look like that, but it seems cloudy. I don't know
> if
> this is normal or not. Is it usually cloudy like this, such that you can't
> see the bottom of the can? Can someone who is familiar with this stuff let
> me know. Thank you.
> 
> Will Drexler
> 
It shouldn't be cloudy Will,  it is most likely crystallized.
Crystallization is visually evidenced by varying degrees of haziness, or
cloudiness, with thickening to the point of a waxy or curd like consistency.
Sometime it will form two layers, one clear the other cloudy.  This is all
nothing more than crystallization.   

ALL epoxy resins are susceptible to crystallization.  Some brands worse than
others, and some batches within a brand name are worse than others.   They
are meta-stable super cooled liquids, and as such they are naturally prone
to crystallization.  The melting point for the crystals is between 120 and
140F.    

To reconstitute (de-crystalize) the resin, place the sealed container in a
bucket of hot tap water.   Agitate every 15 minutes by rotating the can, and
replenish the hot water each time.  Depending on the size of the container,
it will take about  4 hrs. to bring the entire contents of the resin
container up to a temperature sufficient to melt the crystals.  The resin
must remain warm enough long enough to completely melt ALL the crystals.  If
you do not completely melt all the crystals, you are simply leaving a "seed"
to accelerate re-crystalization of the entire container again.   Once
de-crystalized, it should be good for several months when stored at 75+/-5F.


Long before there is any visual evidence (hazy, cloudy appearance) of
crystallization, it may be occurring.  The only way to detect it in the
early stages is to precisely measure the viscosity.  Since we can't do that
easily in our shops, it would not be a bad practice to go through the
reconstitution procedure before using a new shipment or a container that has
been sitting around the shop for few months, especially in the winter time.
It is not necessary to keep the resin hot all the time, but it won't hurt
either.    Conversely, refrigeration simply accelerates crystal formation. 

Gary Hunter

Date: Mon, 10 May 1999 08:26 -0500 (CDT)
From: Michael Pollock <Michael.Pollock@wcom.com>
Subject: Re: COZY: PTM&W Appearance

Will,

I currently use PTM&W from Wicks on my Cozy MKIV and am very pleased
with the results. A couple things that I have noticed is:

The epoxy does not like moisture - so keep the humidity down in shop

The epoxy does not appear to cure well over two days if the cure
temperature is kept below 65 degrees F. I use 78 degree shop
temperature most of the time and can sand parts the next day.

The epoxy appears cloudy when at room temperature - I use a heat box made
of foam with a 15 Watt light bulb inside next to the pump.  It keeps
the temperature around 90 - 100 degrees in the box and the cloudy look
becomes clear.

Other than that, I really like the stuff. I used Hexell 2427 then
SafetyPoxy when I helped to build our Velocity. I did not like the
smell. The PTM&W basically has no smell, even though the fumes are
still dangerous - as all epoxy's are.

I would, however, use SafetyPoxy in the tank area due to the proven
results with aviation fuel.


 

From: "John Slade" <rjslade@bellsouth.net>
Subject: Re: COZY: Epoxy brand compatibility
Date: Tue, 11 May 1999 10:26:46 -0400

Hi Gary,
I hate to bring this up again, but, on the other hand, I dont like to see
incorrect information sit out there unchallenged.

was written
>Incidentally, a friend of mine was telling me he found the internet site
for
>the European equivalent of our NTSB and was horrified to see that about 10%
>of the aviation accident reports in their system involved sailplanes and
>motorgliders having major structural failures.

The following information comes from an LBA (German aviation authority)
report. Hard copy of this report is available on request.

Of all accidents involving gliders or motorgliders in Germany or under
German registration in a foreign country during 1998.

48 Accidents occured in off airport landings after lack of thermal activity
(normally gear failure after hard touch down or collision with obstacles
like trees, fences or rocks)

35 Accidents occured when airplanes came short of the runway and collided
with obstacles or landed too hard.

17 Accidents occured during winch launch, either when the towing rope broke,
or
the airplane got into an uncontrolled attitude.

13 Accidents were Mid- Air- collisions

9  Accidents occured from uncontrolled attitude normally after a stall

4 collisions with obstacles (3flew against a mountain, one hit a
hydroline)

2 airplanes took off with an unlocked canopy and lost the canopy

1 accident happened when the elevator was not connected

1 engine fire

I hope this clarifies the issue of structural failures in Germany.
regards,
John Slade

From: ZeroGCorp1@aol.com
Date: Fri, 14 May 1999 18:41:09 EDT
Subject: COZY: MGS Epoxy-first look

After talking to John Slade a bit, I couldn't help but try out the MGS (I 
have the 335).  After working for nearly 4 weeks with the EZ-poxy all I can 
say is WOW! This stuff has virtually no odor, though I still wear an organic 
respirator, gloves, etc... and is a dream to wet out on the glass. Even at 74 
deg f, it was extremely thin as compared to what I have become used to 
working with.  As it goes on the cloth, it literally disappears on the 
waxpaper. Downside is that it will be much harder to see the fiber bundles to 
make sure they are straight.

The "sticky stuff" dispenser also worked like a dream. I need to get an 
electronic balance and calibrate it, but I will see how this first layup goes.

I think I will be happy with this epoxy system. More info as it becomes 
available. Might do  a GC Mass spec on the vapor to see what is coming off 
that is nasty....

Thanks for all the advice out there. I can live without all of that styrene 
monomer smell.

Ray Cronise

From: ZeroGCorp1@aol.com
Date: Sat, 15 May 1999 09:40:46 EDT
Subject: Re: COZY: MGS Epoxy-first look

Here is the overnight scoop on the MGS 335.

Used just the slow catalyst (pot life approx. 6 hrs.)

shop temp 74 deg F

5:20 p.m. mixed epoxy (using sticky stuff dispenser)
5:20 p.m.- 7:20 p.m.- virtually no noticeable change in viscosity as far as 
wetting cloth goes.  Wets out extremely easy.
9:20 p.m. - approaches starting viscosity and wetting characteristics of EZ 
poxy when first mixed.
11:20 p.m. - becoming thick. Could work with it, but not as easily.
12:20 a.m. 1:00 a.m. past pot life, think and very pliable, but not very 
spreadable. Part still easy to bend, shape, etc...

5:20 a.m. - 8:20 a.m.  Perfect knife trim consitancy....soft like a stick of 
gum.

This will be ideal as I do layups in the morning and in evening. the 10 Hr 
knife trim (at least while temperatures are cool) will work out great. My 
guess is this will drop down to 6-8 hrs. as summer gets here and I'm no 
longer able to maintain my shop at 74 deg F.

Hope this helps out to all that have considered MGS.  I still can't believe 
this stuff has absolutely no odor. Even my wife made the comment last night 
"that stuff isn't nearly as bad as the stuff you have been using."  I guess 
as long as she can get here car in the garage, I'm ok.....

I'm going to play with post cure a bit now...

Ray Cronise
CZ#770

Date: Sun, 16 May 1999 11:54:21 -0400
From: bil kleb <w.l.kleb@larc.nasa.gov>
Subject: Re: COZY: MGS Epoxy-first look

ZeroGCorp1@aol.com wrote:
> 
> I still can't believe this stuff has absolutely no odor. Even my
> wife made the comment last night "that stuff isn't nearly as bad
> as the stuff you have been using."

imho, it is good to hear that you are still using a respirator.
that is the major thing about ez-poxy that i like: it smells!
you quickly get the idea that there is danger cruising around;
no mistaking it.  (kind'a like the stink they add to natural gas?)

-- 
bil

From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Epoxy in General
Date: Thu, 20 May 1999 08:34:23 -0500

> MGS doesn't have an odor, but are the "Invisible" fumes still as hazardous
> as the "Smelly" products?     
> 
Actually, the invisible fumes can be more hazardous than the smelly
products....

The invisible part of MGS is Isophorone Diamine (the most volatile
component).   The American Industrial Hygiene Association (AIHA) recommends
an 8 Hour Time Weighted Average  (TWA)  airborne exposure limit of only 10
ppm.    Which is rather strange considering OSHA has not established any
Permissible Exposure Limit (PEL) or 8H TWA limit on this compound as of YET.


Styrene monomer has had an OSHA PEL/TWA  of 100 ppm for years, and has been
reduce to 50 ppm about 5 years ago.  The Short Term Exposure Limit (STEL) is
100 ppm (short term meaning - up to 15 minutes)      

The following is not to lessen your respect and desire for safety (which I
highly encourage), but to simply to give you some degree of relevance as to
what these numbers mean.    I have been personally monitored in the work
place for exposure to Styrene when I worked with Vinyl Ester Resins that
contain on average 40% wt. styrene monomer.   The monitoring device's lower
detection limit was 5 ppm and it never detected styrene with the ventilation
on.   Without ventilation it rarely detected styrene at the 5-10 ppm level
at the face level.   Placing the monitoring device directly over the
fiberglass laminate (within 1" of the surface) produced a reading of
approximately 100 ppm  with no ventilation.   12" above the laminate was
about 10-20 ppm.    

The interesting part of Styrene is that it has a very low odor threshold.
i.e., You only need 250 parts per BILLION (or 0.25 ppm)  in the air in order
to smell it.   So, as you can see, the low odor threshold of Styrene gives
you a false indication of exposure levels.         

I have never been monitored for exposure to Isophorone Diamine and therefore
will not speculate as to what kind of exposure levels one might see with
this compound in the CBF.  

No matter, you should be pro-active in reducing your exposure levels to any
of these chemicals, just as if you are handling pesticides.   

The most significant and direct route of exposure is dermal - simply wear
gloves and keep it off of you.    

> If You are in a CBF with a window unit type Air Conditioner, how much
> ventalation is enough?  Will a simple oscilating fan be enough, or do you
> need some more robust method of providing fresh air?
> 
The amount of ventilation you need is not that great - Both Styrene and IPDA
will rise into the air -  so, a good size bathroom exhaust fan strategically
placed over your work area will be far better than nothing when all the
doors and windows are shut.

> Airconditioning here in Texas is a must, but so is heating.  What would
> the best way to Heat the CBF?  Could I get a unit that does both?
> 
A window air conditioning unit can heat and cool - AND they can provide
ventilation assistance to the bathroom exhaust fan by bringing in fresh air
as opposed to recirculation of room air.  

Hope this helps :-)


Gary Hunter 


Date: Thu, 20 May 1999 11:45:04 -0700
From: hrogers@slac.stanford.edu (Howard Rogers)
Subject: RE: COZY: Epoxy in General

 Gary Hunter wrote:
>I have been personally monitored in the work
>place for exposure to Styrene when I worked with Vinyl Ester Resins that
>contain on average 40% wt. styrene monomer.

Gary, I have always been curious about Vinyl Ester, but have absolutely no
knowledge about it.  It certainly has built a lot of good, reliable
Glassairs.  Could you tell us a little about it?  Specifically comparing it
to Epoxy for properties, cost, advantages, disadvantages, etc.  Why isn't
it in wider use?  Stoddard Hamilton is a sharp outfit, and one of the best
in the business, and they certainly have had a lot of success with it.
Thanks.

Howard Rogers


From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: COZY: Vinyl Esters
Date: Fri, 21 May 1999 10:33:13 -0500

Gary, I have always been curious about Vinyl Ester, but have absolutely no
knowledge about it.  It certainly has built a lot of good, reliable
Glassairs.  Could you tell us a little about it?  Specifically comparing it
to Epoxy for properties, cost, advantages, disadvantages, etc.  Why isn't
it in wider use?  Stoddard Hamilton is a sharp outfit, and one of the best
in the business, and they certainly have had a lot of success with it.
Thanks.

Howard Rogers

This is probably a lot more than you asked for - but here it goes any - and
put it in the archives.

First of all, it is probably interesting for you all to know that Vinyl
Ester Resins are chemically manufactured from various types of EPOXY resin
feedstocks.   The epoxy reactive sites (oxyrane bridges) are used to react
with an methacrylic acid to form the "vinyl ester"   Essentially the "back
bone" of the primary compound, is the same "back bone" as that of an epoxy
resin.  The resulting vinyl ester is very viscous (tar like),  thus a
reactive diluent is added to the resin.  Styrene monomer is the diluent and
it can be as high 50% by wt.  - but more typically 37%-45% these days.
Other diluents like - Di-Vinyl Benzene - Para - Methyl Styrene can be used -
but Styrene is the CHEAPEST - and toxicology studies are abundant by
comparison to the others.   

Vinyl esters are inherently unstable and will slowly polymerize or gel on
their own.   Inhibitors are added to the vinyl ester/styrene solution to
enhance the products shelf stability.    Vinyl esters are not cured or
crosslinked with curing agents like epoxies.   They are catalyzed like "boat
resins" or "polyester resins"  through the use of various different types of
peroxides, the most common being MEKP.   A metal salt promoter (Cobalt
Napthenate - purple in color) is added to the resin to help generate what
chemists call "free radicals" when it is combined with the peroxide for
speeding the natural reaction along.  The free radicals overpower and
consume the inhibitors allowing the resin to polymerize and crosslink. 

Typically, to cure a vinyl ester - one must first add the Cobalt  -
Usually,  0.1-0.4 % wt. (virtually a few drops), STIR IT IN,  then add
anywhere between 1 - 2 % wt.  MEKP - stir again.  You must avoid letting the
MEKP come in direct contact with the Cobalt as this will result in very
violent and somewhat explosive reaction.   If the temperature is too cool, a
4th component called dimethylaniline (DMA) can be added as an accelerator
(before the MEKP step).  Most of the time, you get your best combination of
cure speed in the laminate and potlife when you adjust the promoter and
catalyst level to obtain about a 30 minute gel time in the mixing cup.   In
my book, a good digital balance capable of weighing tenths of a gram (0.1
grams) is a must for working with this product.  However, I have seen people
work up alternate measuring systems using calibrated measuring cups,
hypodermic syringes, and even counting drops.   Quite a pain compared to
whoopin' up a batch of epoxy - even if you have to use Burt's old beam
balance.  By using a temperature activated or latent catalyst, you can have
an extremely long pot life resin (days), that cures quickly when you heat it
to 180F or better.   I believe Glassair uses this type catalyst system for
producing the vacuum bagged pre-fab parts of their kit plane.     The
builder uses the latter.      Sounds ugly, - but like anything else - you
get used to it.  

Vinyl esters have a limited shelf life - typically 9 - 18 months depending
on the storage temperature.  With refrigeration, it can be extended up to
another year or so.    As the product ages the inhibitor level declines
allowing the resin to react on itself and grow in viscosity.  As you can
imaging - the older a resin is, the less catalyst it needs to produce the
same gel time.   Which really complicates "whoopin up a batch" with any
consistency.  

Vinyl Esters have many pros and cons like any of the epoxy resins we have
become familiar with.   Probably the most notable PRO is that they develop a
larger percentage of their "ultimate" thermal and chemical resistance
properties with just a room temperature (RT) cure than do epoxies.  They are
inherently "tough".  They also have superior thermal and chemical stability
over the typical epoxies that we use, and the "polyester boat resins" used
to make many of the prefab parts on other kit planes like the RV.  They
develop this kind of stability with a simple ambient cure because the
reaction is highly exothermic.  Even thin laminates can generate a
considerable amount of heat - but vinyl esters benefit from a post cure just
as an epoxy does.  ( I had to say that ).  CONS - We already talked about
the rather inconvenient mixing ratios and hazards.   They inherently shrink
more than epoxies (about twice).   Except for EZ-Poxy, they smell (styrene)
compared to epoxies.    They always produce a sticky surface on cure.   This
is caused by air inhibition of cure - similar, but not quite the same as the
amine blush in epoxies.  And as with epoxies, peel plying will take care of
it.   As with just about any chemical compound, they are skin and eye
irritants, and some people develop a sensitivity to them and become allergic
(usually, this is from the styrene component more than anything else).
They are flammable liquids in the uncured state.   The peroxide catalyst can
blind you if you get it in your eyes.   

In 55 gallon drum quantities - vinyl esters cost about $2.75 / lb.  (about
$24 / gal.)    The price increases exponentially as the container size
decreases, just like it does for epoxies.  The catalysts are several times
more expensive than the resin.  However, at the small usage levels required,
they only contribute ~.25-.50 cents / lb. ($2-4 / gal.) to the total system
cost.   For comparison, my favorite epoxy/curing agent system (EPON Resin
862 / EPI-CURE 3234) drum price is $2.33 / lb (about $21 / gal.).  As far as
epoxies are concerned, this system is about as cheap as it gets.  So, add
middle man costs for making the epoxy into an MGS, Aeropoxy or EZ-Poxy
system and the epoxy will cost about the same as the vinyl ester.     

The reason we CAN'T use vinyl esters for building our airplanes (EZ types)
is that the Styrene component in the vinyl ester resin will dissolve the
styrofoam used for the core in our wings.   PERIOD.    

NOW, I know what you are all thinking.  EZ-Poxy has styrene in the hardener,
- how come it doesn't dissolve the styrofoam cores ?   The level of styrene
in the EZ-Poxy hardener is very low compared to that in the vinyl ester.  In
addition, I have been told by CPD that the styrene is somehow complexed with
the hardener component (methylene dianiline or MDA), thus it really doesn't
behave like styrene any more.  Likewise, the MDA doesn't behave like MDA
anymore - at least from a crystallization standpoint.  This is proprietary
technology and details are sketchy - but I'll go as far as to speculate that
not all the styrene is complexed and residual quantities of styrene
(probably less than 1%) are sufficient enough to retain the odor.  As, I
said before - it only takes 0.25 ppm of styrene in the air in order for it
to smell as if you have your head inside a bucket with it.    So, it gives
you a false indication as to the actual level of pure styrene in the
hardener.  In actuality, the level of residual virgin styrene is not enough
to change the overall solubility parameters of the epoxy resin/hardener
mixture to dissolve or hurt the styrofoam.   

In fact, polystyrene foam is a very non-polar substance - meaning it is
difficult for epoxy to bond to it.  This is why Rutan wants us to be certain
to force epoxy micro into the pores of the foam to obtain a mechanical lock
or bond to the foam.  The small level of residual virgin styrene in EZ-Poxy
is probably somewhat beneficial in this scenario.   Based on my background
and experience in the area, I will, again, go as far as to speculate that
the styrene level could be just enough to "bite" into or "etch" the
non-polar surface of the styrene and may actually improve the adhesive
characteristics of the resin to the foam without hurting it.    After all,
polystyrene is made from styrene monomer.  

WOW  -  I can't believe wrote the whole thing.        
  
Hope this is clear :-)

Gary Hunter


Date: Fri, 21 May 1999 12:20:18 -0700
From: hrogers@slac.stanford.edu (Howard Rogers)
Subject: Re: COZY: Vinyl Esters

Gary Hunter wrote:


...
>4th component called dimethylaniline (DMA) can be added as an accelerator
>(before the MEKP step).

<snip>
 In
>addition, I have been told by CPD that the styrene is somehow complexed with
>the hardener component (methylene dianiline or MDA), thus it really doesn't
>behave like styrene any more.
<snip>

Thank you, Gary, for shedding light on this subject.  I'll stick to my
epoxy of choice, thanks, which brings me to one more question:

I have been off the EZ project for some time, but I may finally be getting
my life ordered such that I can resume.  My epoxy of choice has always been
Saf-T-Poxy/ EZ poxy.  I seem to remember that Burt swore off the stuff
because of the MDA.  How bad is it?  Is EZ-poxy the only only one we
commonly use that has the MDA?  I don't have that much glass structure to
go (mostly little stuff), and I'm not fond of the idea of switching horses
in the middle of the stream.  I would have to do some "gearing up" to go
with MGS, but if there is a signifigant health risk with the MDA, I will
definitely consider it.

-Howard Rogers


From: "Hunter GA (Gary)  at MSXSCC" <GH334766@MSXSCC.shell.com>
Subject: COZY: MDA in EZ-POXY - was Vinyl Esters
Date: Fri, 21 May 1999 15:49:51 -0500

> I seem to remember that Burt swore off the stuff
> because of the MDA.  How bad is it?  
> 
Rutan is concerned about liability, a valid reason to change positions.
MDA is probably one of the most widely mis-understood compounds from a
safety and handling stand point.   MDA does not volatilize into the air
unless it is heated to extreme temperatures (over 200F).   So, at ambient
temperature conditions,  MDA poses less hazard from a respiratory standpoint
than more volatile amines like the IPDA .   The most significant route of
exposure is dermal.    Keep it off you, and you will be fine.  

> Is EZ-poxy the only only one we
> commonly use that has the MDA?  
> 
Yes

> I don't have that much glass structure to
> go (mostly little stuff), and I'm not fond of the idea of switching horses
> in the middle of the stream.  I would have to do some "gearing up" to go
> with MGS, but if there is a signifigant health risk with the MDA, I will
> definitely consider it.
> 
In my opinion - the health risk is no greater than any of the other products
available.   If you keep take the proper precautions to avoid over exposure
as you should with any other epoxy resin and curing agent combination, you
will be just as safe with EZ-poxy.  

Wear gloves,  have ventilation and keep it off of your skin.  And,  if you
accidentally get some on you (and you will) do not wash it off with
solvents.   Use soap and water.  

The best plan is keep them off of you.  ANY RESIN or CURING AGETN - PERIOD.

Gary Hunter

Date: Fri, 21 May 1999 16:02:59 -0500 (CDT)
From: Tom Brusehaver <tgb@cozy.core.wamnet.com>
Subject: Re: COZY: MDA in EZ-POXY - was Vinyl Esters


>Rutan is concerned about liability, a valid reason to change positions.
>MDA is probably one of the most widely mis-understood compounds from a
>safety and handling stand point.   MDA does not volatilize into the air
>unless it is heated to extreme temperatures (over 200F).   So, at ambient
>temperature conditions,  MDA poses less hazard from a respiratory standpoint
>than more volatile amines like the IPDA .   The most significant route of
>exposure is dermal.    Keep it off you, and you will be fine.  

I thought MDA caused liver cancer?

Date: Fri, 21 May 1999 15:52:38 -0700
From: hrogers@slac.stanford.edu (Howard Rogers)
Subject: Re: COZY: MDA in EZ-POXY - was Vinyl Esters


>Wear gloves,  have ventilation and keep it off of your skin.  And,  if you
>accidentally get some on you (and you will) do not wash it off with
>solvents.   Use soap and water.

Thankfully, I have always followed the advice above (almost).  I haven't
always been too careful about the breathing exposure, but I plan to pay
more attention to that in the future.  Also, I usually kept some ethyl
alcohol handy for wiping off a drop or two of mixed resin, should I
accidentally get some on my skin.  It would have taken a lot longer, and
been a lot more difficult to wash with soap and water, most of the time.
Besides, I didn't get the impression that the stuff was very soluable in
water.  could you elaborate?

>
>The best plan is keep them off of you.  ANY RESIN or CURING AGETN - PERIOD.
>
>Gary Hunter

Amen!  I reacted to epoxy once, requiring cortisone shots, etc.  It was on
my first day of work here, in 1976.  I have been REAL careful ever since.
The type: Epon.  Sorry, I don't remember which one.

Howard Rogers


From: N27EZ@aol.com
Date: Sat, 22 May 1999 00:34:18 EDT
Subject: COZY: Re: [c-a] Vinyl Esters


In a message dated 5/21/99 7:20:12 PM, GH334766@MSXSCC.shell.com writes:

<< Gary, I have always been curious about Vinyl Ester, but have absolutely
no knowledge about it.  It certainly has built a lot of good, reliable
Glassairs.  Could you tell us a little about it?  Specifically comparing
it to Epoxy for properties, cost, advantages, disadvantages, etc.  Why
isn't it in wider use?  Stoddard Hamilton is a sharp outfit, and one of
the best in the business, and they certainly have had a lot of success
with it.  Thanks.
 >>

Vinyl ester is cheap, strong, stinks like hell, gives you a headache, and 
makes your gloves all sticky within minutes.  It must be promoted with rocket 
fuel and has a short shelf life. Every chance I get I use epoxy and I could 
not wait to finish critical areas on the glastar so I could switch over to 
West Epoxy on non critical structures. 
John Steichen, glastar, Defiant, varieze

Date: Tue, 29 Jun 1999 05:20:01 -0700 (PDT)
From: "Jim H." <stylemismatch@yahoo.com>
Subject: COZY: Epoxy (MGS)  hardener question



While on the subject of epoxy and hardeners, does anyone have
information from MGS as to whether or not it is acceptable to pre-mix
the fast and slow hardener?  (I learned early in organic chemistry that
the order of mixing components can be very important, i.e. if the fast
and slow hardener have any components that react with each other the
final product won't be acceptable.)  


Thanks

Jim Hocut
jhocut@mindspring.com

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Get your free @yahoo.com address at http://mail.yahoo.com

From: "John Slade" <rjslade@bellsouth.net>
Subject: Re: COZY: Epoxy (MGS)  hardener question
Date: Wed, 29 Sep 1999 09:30:33 -0400

Jim,
I think mixing the MGS hardeners in advance is normal and not a problem.
I typically pour half a can of each into my pump's hardner container, use
the pump until the level gets low, then add some more.  How else could you
do it with a pump?
John Slade
Cozy #757 N386JS Chap 13
http://kgarden.com/cozy

>
>While on the subject of epoxy and hardeners, does anyone have
>information from MGS as to whether or not it is acceptable to pre-mix
>the fast and slow hardener?  (I learned early in organic chemistry that
>the order of mixing components can be very important, i.e. if the fast
>and slow hardener have any components that react with each other the
>final product won't be acceptable.)
>


From: Militch@aol.com
Date: Tue, 29 Jun 1999 10:22:47 EDT
Subject: Re:  COZY: Epoxy (MGS)  hardener question


In a message dated 6/29/99 12:21:16 PM, stylemismatch@yahoo.com wrote:

>While on the subject of epoxy and hardeners, does anyone have
>information from MGS as to whether or not it is acceptable to pre-mix
>the fast and slow hardener?

I believe I saw an earlier submission on this list from the MGS manufacturers 
that talked about the flexibility of MGS.  The slow and fast hardeners can 
certainly be mixed at the instant you measure them out to make a cup of 
epoxy, and there were no caveats about doing this before-hand.  Also, others 
on this list have said that they premix their MGS for use in a pump.  I 
prefer to do it in real time.  Sometimes I want a fast set, sometimes I want 
to maximize the working time, and sometimes I want it in the middle.  I have 
also found that using the fast hardener only, in my quite cool basement, 
still results in an exotherm almost every time, so I only use 100% fast-stuff 
when I am mixing up a very small quantity and am going to use it all in the 
next couple of minutes.

Peter Militch Cozy Mark IV #740 Chapter 6

Date: Tue, 29 Jun 1999 08:20:39 -0700 (PDT)
From: "Jim H." <stylemismatch@yahoo.com>
Subject: Re: COZY: Epoxy (MGS)  hardener question



> I typically pour half a can of each into my pump's
> hardner container, use
> the pump until the level gets low, then add some
> more.  How else could you
> do it with a pump?


Well, I don't use a pump, I use a scale and store epoxy and hardener in
plastic squeeze bottles which stay sealed when not in use, and it's
still a pain to have to figure out how much fast and how much slow to
use every time.  

My point is that, not knowing the chemistry of the hardener, there is a
small possibility that there is some component in the fast hardener
that, over time, will react with something in the slow.  After enough
time and enough of that reacting you will no longer have the proper
ratio of hardener to resin when you mix your epoxy.  I seriously doubt
if there's any problem with doing this, but since my butt and my wife
and kid's butts are going to be flying in this plane I want to err on
the safe side instead of making an assumption about the suitability of
doing this.

Jim 
_________________________________________________________
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From: "Hunter, Gary GA PECCHEM" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Epoxy (MGS)  hardener question
Date: Tue, 29 Jun 1999 11:06:19 -0500

Jim asked:

> While on the subject of epoxy and hardeners, does anyone have
> information from MGS as to whether or not it is acceptable to pre-mix
> the fast and slow hardener?  
> 
Yes, you can premix the curing agent components prior to adding to the
resin.   This is totally acceptable and normal industry wide.   

Gary Hunter


Date: Sat, 03 Jul 1999 23:57:06 -0400
From: George Berven <gberven@erols.com>
Subject: [Fwd: RE: COZY: Epoxy (PTM&W)hardener 


Gary Hunter writes:
	FOR MOST EPOXY HARDENERS -  "When stored in the proper and/or original
container (not including the pump reservoir, under normal (70+/- 15F)
temperature conditions, free from moisture and sunlight and other
contaminants, the hardener should have unlimited shelf life." 

Scott from AEROPOXY technical support confirms this for PH3990 hardener.
He also said to watch out for a pink hue in the hardener because this
means it has started to oxidize.

Today I opened my two year old can of hardener. On the top rim (before
prying the stopper plug) it was dark & pink, as advertised.  After
opening and transfering to a clear container, the color was an AMBER
very similar to motor oil or a light maple syrup.

--------Should it (PH3660) be this dark?-------

BTW, the resin was fine (no crystalization), almost clear.

Thank again,
George	gberven@erols.com
Presently driving myself crazy, wife too, with all the small details.

From: "Russ Fisher" <rfisher1@rochester.rr.com>
Subject: Re: [Fwd: RE: COZY: Epoxy (PTM&W)hardener 
Date: Sun, 4 Jul 1999 09:34:48 -0400

-----Original Message-----
From: George Berven <gberven@erols.com>


>Today I opened my two year old can of hardener. On the top rim (before
>prying the stopper plug) it was dark & pink, as advertised.  After
>opening and transfering to a clear container, the color was an AMBER
>very similar to motor oil or a light maple syrup.
>
>--------Should it (PH3660) be this dark?-------

My 3660 has always been pretty dark - should be no problem.

Russ Fisher


Date: Mon, 28 Jun 1999 14:39:48 -0400
From: George Berven <gberven@erols.com>
Subject: COZY: Epoxy hardener

Another quickie,

I've read and understood the archives about resin crystalization and
reconstitution by heating; BUT, nothing is mentioned about the hardner
WRT shelflife.  In {Sport Aviation (May '99 pg.107),} Ron Alexander
writes, 
	"Resins may be stored for several years prior to being used.  This is
termed thier "shelf-life."  However, with epoxy resins the accompanying
hardner usually has a shelf life of less than one year."

Is there any concrete information out there?  I have not done a lay-up
with the stuff and therefore haven't scratch tested it. It's AEROPOXY
but that shouldn't really matter. Hardner is 2+ years old. 

Thanks,   George...   gberven@erols.com

Date: Mon, 28 Jun 1999 14:17:25 -0700
From: hrogers@slac.stanford.edu (Howard Rogers)
Subject: Re: COZY: Epoxy hardener


>Is there any concrete information out there?  I have not done a lay-up
>with the stuff and therefore haven't scratch tested it. It's AEROPOXY
>but that shouldn't really matter. Hardner is 2+ years old.
>
>Thanks,   George...   gberven@erols.com

My favorite saying, in this situation, is "When in doubt, pitch it out!"
Actually, I usually end up being able to use the stuff for some
non-aircraft project.  Amazing how many things you can think of to build,
once you know how to do it with glass!

-Howard Rogers


From: "Russ Fisher" <rfisher1@rochester.rr.com>
Subject: Re: COZY: Epoxy hardener
Date: Mon, 28 Jun 1999 20:42:05 -0400

George,

Call PTM&W at (800) 421-1518 and ask for Scott in support.  I had a similar
question and I think that as long as the container is unopened, the shelf
life is fairly long.  My hardener was in my pump for about 9 months and
froze the pump up solid.  He recommended that I discard that hardener and
replace with fresh.

Russ Fisher


>Another quickie,
> "Resins may be stored for several years prior to being used.  This is
>termed thier "shelf-life."  However, with epoxy resins the accompanying
>hardner usually has a shelf life of less than one year."
>
>Is there any concrete information out there?  I have not done a lay-up
>with the stuff and therefore haven't scratch tested it. It's AEROPOXY
>but that shouldn't really matter. Hardner is 2+ years old.
>
>Thanks,   George...   gberven@erols.com

From: "Hunter, Gary GA PECCHEM" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Epoxy hardener
Date: Tue, 29 Jun 1999 06:30:28 -0500

George asks:

> Is there any concrete information out there?  
> 
Concrete is not even related to epoxy resins and hardeners.....

Just joking....

FOR MOST EPOXY HARDENERS -  When stored in the proper and/or original
container (not including the pump reservoir, under normal (70 +/- 15F)
temperature conditions, free from moisture and sunlight and other
contaminants, the hardener should have unlimited shelf life.   

One exception to the rule is the MDA containing EZ-Poxy hardeners that
contain some styrene monomer that can form a gel over time.  In addition,
these hardeners can crystallize.  If stored properly, it should have at
least a 1 year shelf life, and quite possibly 2 and even 3 years.
Particularly if you refrigerate it.   Like, I said - this is an exception to
the rule and the only curing agent I know of that refrigeration will enhance
the storage life of the product.   

When in doubt as to the age or condition of a resin or curing agent, it
would be prudent to conduct a test lay-up and do scratch tests as Rutan
prescribed prior to using it in your structure.    And, if that doesn't make
you more comfortable about it, you can always use it for non-structural
applications, or as another lister suggested, other projects around the
house.   Don't pitch it needlessly.    

Gary Hunter

From: "Hunter, Gary GA PECCHEM" <GH334766@MSXSCC.shell.com>
Subject: RE: RE: COZY: Epoxy hardener
Date: Tue, 29 Jun 1999 07:20:00 -0500

Rego Burger comments:
RSA

> Jokes aside some builders (engineers) use an Epoxy system for concrete
> strength enhancements here in this country...
> :-)
> 
Yes, here too.   Known as epoxy fortified concrete.  Shell's EPI-REZ WD510
is most commonly used in this application.   It is a water dispersible epoxy
resin.   Washes up with water.     

Just trying to get a chuckle... 

Gary 



Date: Mon, 28 Jun 1999 14:58:46 -0400
From: Phillip <LUV2AV8@compuserve.com>
Subject: COZY: Humidity....

Is there a humidity level at which you should not do a layup??

Phillip Sill, #707
Finishing Chapter 4

From: "Russ Fisher" <rfisher1@rochester.rr.com>
Subject: Re: COZY: Humidity....
Date: Mon, 28 Jun 1999 20:49:19 -0400

Phillip,

There has been all kinds of controversy on this topic - check the archives.
Some have problems while others seem to have none.  Check with the
manufacturer of your resin also.  They would have specific numbers, although
they will probably recommend that you lay up in as low a humidity as
possible.

Russ Fisher


>Is there a humidity level at which you should not do a layup??
>
>Phillip Sill, #707
>Finishing Chapter 4
>

From: "Hunter, Gary GA PECCHEM" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: Humidity....
Date: Tue, 29 Jun 1999 06:45:58 -0500

Phillip Sill, #707 asked:

> Is there a humidity level at which you should not do a layup??
> 
It is best to avoid rain and fog producing conditions.  Some hardeners are
worse than others in developing an "amine blush" or "sweat-out" under these
conditions.

Gary Hunter

Date: Tue, 29 Jun 1999 08:14:33 -0400
From: Paul Krasa <p.w.krasa@larc.nasa.gov>
Subject: Re: COZY: Humidity....

Hopefully, the distinguished gentleman from Texas, Gary Hunter, will chime
in on this one.

Here are my two cents.  Each epoxy resin system is unique.  Systems such as
EZ Poxy are less susceptable to humidity problems like amine blush where as
other systems which are well discussed in the archives are highly
susceptable to amine blush.  Other problems related to humidity are bond
strength.  The same systems which have amine blush problems often have a
bond line strength problem.

My personal recommendation to the group and all starting builders is use EZ
Poxy.  It has a long proven track record in varying environments.  It may
stink, but it does not exhibit the problems of other epoxy resin systems.

Paul
Long EZ 214LP


At 20:49 6/28/99 -0400, Russ Fisher wrote:
>Phillip,
>
>There has been all kinds of controversy on this topic - check the archives.
>Some have problems while others seem to have none.  Check with the
>manufacturer of your resin also.  They would have specific numbers, although
>they will probably recommend that you lay up in as low a humidity as
>possible.
>
>Russ Fisher
>
>
>>Is there a humidity level at which you should not do a layup??
>>
>>Phillip Sill, #707
>>Finishing Chapter 4
>>
>
>
>

From: "Chris Byrne." <jcbyrne@ozemail.com.au>
Subject: COZY: RE:MGS Hardener
Date: Wed, 30 Jun 1999 08:33:11 +1000

I am using the L335 and posed the same question to Johannes Meunier at MGS
last year, he replied with the following.

>You can mix the two hardeners and store them for a longer period of time
without loss of quality. Important is, that the hardeners are not exposed to
air. Amines react with the Carbondioxide  of the air, forming white crystals
which reduces the quality of the material. To avoid this, always keep the
buckets thoroughly sealed, then the material is storable for min. 1 year.
Mixing of the two hardeners is common practice for that system and is
accepted by the German Federal Aviation Authority. This system was specially
designed for being able for that mixing in order to allow users to be
flexible in the potlife they need. The mechanical properties stay the same
as well as the heat resistance of that system.<


Chris Byrne
Sydney


From: Gunrider@aol.com
Date: Tue, 13 Jul 1999 10:53:30 EDT
Subject: COZY: CHANGING EPOXY

I have run out of my RAES and it has been discontinued.  I have the Sticky 
Stuff dispenser at a 4 to 1 ratio.
Wicks reccomends the Composite epoxy CPD 4426 to keep the same ratio.
Is this stuff good enough or should I take the risk of changing my pump 
ratios?
I don't need the slow cure anymore because I'm working in a/c.
Thanks for your reply.
Hugh Farrior
The canopy is next!

From: "Hunter, Gary GA PECCHEM" <GH334766@MSXSCC.shell.com>
Subject: RE: COZY: CHANGING EPOXY
Date: Tue, 13 Jul 1999 10:54:10 -0500

Composite Polymer Design now produces the RAES and RAEF systems you have
been using.   However, they have been given new names -  They are as
follows:

RAEF is now  -   CPD 4426 (Resin) /  CPD 9376 (Curing Agent) 
RAES is now  -   CPD 4426 (Resin) /  CPD 9377 (Curing Agent)  

The slow curing agent has a blue die in it now to help you differentiate
which of the two curing agents you are using when you have both on hand.

You can use these products in place of the older RAE systems without worry.

Gary Hunter



> -----Original Message-----
> From:	Gunrider@aol.com [SMTP:Gunrider@aol.com]
> Sent:	Tuesday, July 13, 1999 9:54 AM
> To:	cozy_builders@canard.com
> Subject:	COZY: CHANGING EPOXY
> 
> I have run out of my RAES and it has been discontinued.  I have the Sticky
> 
> Stuff dispenser at a 4 to 1 ratio.
> Wicks reccomends the Composite epoxy CPD 4426 to keep the same ratio.
> Is this stuff good enough or should I take the risk of changing my pump 
> ratios?
> I don't need the slow cure anymore because I'm working in a/c.
> Thanks for your reply.
> Hugh Farrior
> The canopy is next!

Date: Tue, 13 Jul 1999 08:55:39 -0700
From: Michael Antares <mantares@pacbell.net>
Subject: Re: COZY: CHANGING EPOXY

At 10:53 AM 7/13/99 EDT, you wrote:
>I have run out of my RAES and it has been discontinued.  I have the Sticky 
>Stuff dispenser at a 4 to 1 ratio.
>Wicks reccomends the Composite epoxy CPD 4426 to keep the same ratio.
>Is this stuff good enough or should I take the risk of changing my pump 
>ratios?
>I don't need the slow cure anymore because I'm working in a/c.
>Thanks for your reply.
>Hugh Farrior
>The canopy is next!
>
I switched to the CPD 4426 after RAE and frankly don't notice any difference
at all which is to say I'm very pleased with it.
1456 Jasmine Circle
Rohnert Park, CA 94928
707.773.1475
Systems engineering hardware/software

Date: 21 Jul 99 19:54:05 EET DST
From: Cevat SUNOL <csunol@usa.net>
Subject: COZY: MGS epoxy on fuel tank



Hii 

When I looked to discusion between yours my questions about engines and
propelers are very simple but I need some informations about props and
Lycoming O-320 series engines dash number. I think to use 160 hp engine
suitable for variable pitch prop. Please send your suggestions.
and one more questions about epoxy on fuel tank. I am using MGS L285 / H286
epoxy system on my Cosy Classic and I want to learn that anyone used this
epoxy system on fuel tank or know something about this .


Regards
Cevat Sunol

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Get free e-mail and a permanent address at http://www.netaddress.com/?N=1

Date: 	Sat, 07 Aug 1999 23:08:38 -0600
From: "Capital Steel Inc." <capitalsteel@compusmart.ab.ca>
Subject: COZY: Epoxy

Unless my hearing is getting even worse G A Hunter at the EAA forum,
Friday afternoon at 1600hrs said, "Non of the West system Epoxies are
suitable for your composite and besides they are too expensive".
Here in Canada they are second cheapest of the ones I priced.  Second
they are very user friendly and Third the 105/209 is in the approved
list of the Cozy letters (56-6).
Is this his private opinion?
Does anyone know how RAF/Nat test or approve these and are the test
results available even if at a price.
Joe Toop

From: "Russ Fisher" <rfisher1@rochester.rr.com>
Subject: Re: COZY: Epoxy
Date: Sun, 8 Aug 1999 10:52:46 -0400

Joe,

>Unless my hearing is getting even worse G A Hunter at the EAA forum,
>Friday afternoon at 1600hrs said, "Non of the West system Epoxies are
>suitable for your composite and besides they are too expensive".

All of the West System epoxies except the ProSet are designed for boat use
and are WAY too soft to use as a laminating resin.  The ProSet is the very
expensive one Gary referred to.

>Here in Canada they are second cheapest of the ones I priced.  Second
>they are very user friendly and Third the 105/209 is in the approved
>list of the Cozy letters (56-6).


Indeed, 105/209 is listed as an approved resin, ONLY for finishing and
contouring, NOT for laminating.  Look in your plans, chapter 3, page 5, the
last paragraph of Cold Temperature Tips.  It clearly states that West System
105/206 (209) is softer and should not be used for laminating.

>Is this his private opinion?


No, it is fact.

I hope you are not very far in your building progress if you have used
105/209 as your laminating resin.  It MUST be scrapped and done over.  The
resin was formulated for use in coating or bonding fiberglass to wooden boat
hulls.  It is made softer because a hull is subject to more abrasion and
impact than an airplane, therefore has to have the resilience to withstand
such abuse without cracking.  It depends upon the stronger core materials
such as plywood and planking for its strength and resistance to bending.
Foam core does not have the strength.

Regards,

Russ Fisher


Date: Mon, 09 Aug 1999 09:03:26 -0400
From: Paul Krasa <p.w.krasa@larc.nasa.gov>
Subject: Re: COZY: Epoxy

What Gary said was that the West Systems Epoxies are not suitable for
structural components. Most people do use them for fillers or
non-structrual layups.  I would be suprised if Nat approved West for
structural layups as you imply.  West Systems says its epoxies are not for
aviation use.

Paul

At 23:08 8/7/99 -0600, Capital Steel Inc. wrote:
>Unless my hearing is getting even worse G A Hunter at the EAA forum,
>Friday afternoon at 1600hrs said, "Non of the West system Epoxies are
>suitable for your composite and besides they are too expensive".
>Here in Canada they are second cheapest of the ones I priced.  Second
>they are very user friendly and Third the 105/209 is in the approved
>list of the Cozy letters (56-6).
>Is this his private opinion?
>Does anyone know how RAF/Nat test or approve these and are the test
>results available even if at a price.
>Joe Toop
>
>
>

From: "Hunter, Gary GA PECCHEM" <GH334766@MSXSCC.shell.com>
Subject: COZY: RE: Oshkosh Forum / RUBBER GLOVES
Date: Mon, 23 Aug 1999 10:54:30 -0500

Thanks, Gary,
    I received both the e-mail and hard copies of the forum material and 
other literature you sent.  I really appreciate it.  Just knowing that my 
unopened SAFE-T-POXY hasn't self destructed because it is over 2 years old 
has made the time spent sweating out the heat at the Oshkosh forum worth 
while.
    One question (one MORE question, actually!); Lots of builders use latex 
gloves.  I remember reading somewhere or hearing that latex did not provide 
adequate protection since the gloves actually have microscopic holes in them

that allows the bad stuff to get through.  And that barrier creams should
not 
be used under gloves.  Although I've used nitrile gloves, the ones I have
are 
pretty thick and not as nice to work with as the thinner latex disposable 
gloves.  So is latex no good and where can you get thin nitrile gloves?  
Aircraft Spruce sells latex and butyl.
    Again, thanks a lot.  Fred

Fred, 

In actuality, any rubber glove type can have microscopic holes in them.
When it comes mass produced, "cheap" and "thin" gloves, there is no
guarantee they will not have holes in them unless they are tested like
condoms.   When it comes to gloves there is a lot truth in the saying, "You
get what you pay for". 

Latex gloves were developed for the medical field.  Main emphasis was "good
feel" (sensitivity) and adequate protection from human body fluids, and
"CHEAP".  Never, were they intended to provide long term protection from
industrial chemicals.   But, because they are cheap, and have good "feel",
people like you and I find them easy to work with.   They do provide some
level of chemical protection too.   However, recently, the medical industry
has discovered people are developing a sensitivity and in some cases deadly
allergic reactions to latex gloves.  This is not good.

As part of my job, I have attended training courses on gloves for worker
safety.  In short, NO glove is completely impervious to all chemicals. They
are tested and rated for PERMEATION RATE for each different type chemical.
Certain type rubber compounds (latex, nitrile, butyl) have lower permeation
rates with certain chemicals than others.  The thicker the rubber glove, the
longer it takes for a chemical to permeate.  In many cases, a rubber that is
exceptionally good at resisting permeation of epoxy resins and curing
agents, are really bad at other things you just happen to be working with at
the same time - like solvents - Acetone, MEK, Lacquer Thinner, etc. (as is
the case with nitrile)  Gloves that provide many hours of protection. (a
full "worker shift") primarily what chemical companies are interested in)
are relatively thick and designed for use in harsh environments (high
abrasion) over long periods of time.   And as such, they have poor feel and
are relatively expensive.   

Butyl rubber gloves are perhaps one of the best at providing good permeation
resistance to a fairly broad spectrum of chemicals.   But they are fairly
expensive, and as such we have a tendency to re-use them over and over, and
even perhaps beyond the point of their protective life span.  Cleaning the
glove off with a solvent to allow future use of the glove doesn't work
either.   Many times, the solvent will act as carrier, making the hazardous
resin or curing agent permeate even further and faster into the rubber,
shortening the protective life span of the glove in total.
  
>From these training courses, one can easily conclude that ANY glove is
adequate protection, provided you change them out frequently enough to keep
ahead of the permeation rate.   In our scenario as homebuilders,  we need a
glove that will last a least an hour or two.  Latex has proven quite
adequate for many and is certainly better than no glove at all.  If you are
concerned about the adequacy of latex protection or the toxicity of the
latex itself, you should consider alternatives. 

CHEAP seems to be the primary denominator in the homebuilding world.   In my
opinion, nitrile rubber gloves are a good alternative although they do not
resist solvents very well.  I am not referencing the industrial or harsh
environment grades that are thick and have poor feel.  I am referring to the
thinner versions packaged in boxes of 100 much like latex gloves.  They have
pretty good feel, maybe not as good as latex.  They are more expensive than
latex, but still cheap enough to be seriously considered - DISPOSABLE.   I
buy them from Harbor Freight, - typically a box of 100 (50 pair) is $12 and
on sale they can be had $10 / box.  -   20-24 cents / pair ain't bad.
Other industrial supplies are located in major cities throughout the
country.   But expect the price to be double Harbor Freight.   

Depending on what job I am about to do I will put on a double layer of
gloves.  i.e., If it's ten minute job, one pair is sufficient.   If I have a
job I think will either be long in duration, or has the potential to cause a
tear, or may "gook" up the glove beyond the point of usefulness, I will put
on a second pair over top the first pair - before starting any work with the
resins. 
  
What this does is:

1). Increases the life span of the "glove protection" considerably.  What
little gets through the first glove, will take much longer to get through
the next layer.

2).  Sweating hands inside the glove makes changing gloves "on the fly" a
real challenge (unless you are particularly adept at putting baby powder
on).  Personally, I have found it much easier and quicker for me to peel off
the outer layer of glove and put on a new glove right pronto.  This works
really well for those instances when a glove is just too gunky to keep
working with it.  It is even handy when you accidentally cut a glove.   Even
if you cut both layers of glove - if you stop before any resin contacts your
hand, you can peel off the outer layer glove and slip a new glove on in a
matter of seconds.  This is far better than continuing to work with a hole
in your glove, and much quicker than removing gloves from both hands,
re-powdering and placing new gloves on.  

I never re-use my gloves.   If I run out of gloves, I simply don't work
until I get more.  

DO NOT use Barrier Creams inside the gloves.  Barrier creams work best when
they are dry.  Since our hands tend to sweat profusely inside the gloves,
the barrier cream dissolves in the sweat and becomes less effect.   In the
event a glove tears after your hand has begun sweating, the barrier cream
won't be of much benefit.  Simply put, it is a waste of money under a glove.
It would be cheaper and more effective to put on two layers of gloves.

HOWEVER, DO  put the barrier cream on your forearms - from the wrist up to
about your elbow or maybe beyond depending on how sloppy you are with epoxy
resin.  

Since nitrile gloves are not that good in solvents, avoid "deliberately"
using them in solvents and acquire a thicker butyl glove specifically for
that purpose.  Solvents tend to come into play when we clean our tools after
a lay-up.   It is more difficult to avoid the use of clean-up solvents when
it comes to scissors and expensive squeegees.  But, we can avoid  the use of
solvents when it comes to brushes.  Again, "cheap" is the common denominator
here and Harbor Freight sells 2" wide "chip brushes" for about $12 / box of
36.   Use them once and throw it away.   I know what many of your are going
to say - "They tend to shed hairs into your lay-up".   Yes they do, and "you
get what you pay for" pertains here too.  BUT, I have found that if you cut
off about half the length of the brush hairs, the loose hairs will "fly out"
out of the brush more easily and completely when you "flick" it over your
hand, the corner of the bench top, or the sticky side of a piece duct tape.
This process gets the bulk of the loose hairs out of the brush, but you will
still get few inclusions in your lay-up from time to time.  Personally, I am
not that concerned over "a few" camel hairs in my lay-up.  And if I am not
mistaken, I believe it is permissible by Rutan inspection criteria to have
"a few" brush hair inclusions.  Another good reason for cutting the brush
hairs short is that it improves "stroking" and "stippling" performance of
the brush considerably.  

I know this is lot more than you asked for, but it is the best complete
answer I can give.  

Gary Hunter


From: "Russ Fisher" <rfisher1@rochester.rr.com>
Subject: Re: COZY: RE: Oshkosh Forum / RUBBER GLOVES
Date: Mon, 23 Aug 1999 19:12:56 -0400

>nitrile rubber gloves are a good alternative although they do not
>resist solvents very well.  I am referring to the
>thinner versions packaged in boxes of 100 much like latex gloves.  They
have
>pretty good feel, maybe not as good as latex.
>Depending on what job I am about to do I will put on a double layer of
>gloves.  i.e., If it's ten minute job, one pair is sufficient.

FWIW,  I use a triple layer:  First, a cotten liner - relatively inexpensive
and washable.  This is used to absorb the inevitable perspiration.  I get
mine through the hospital I work at, not sure where they are available to
the gen. public.  Second, the thin nitrile gloves mentioned above.  These
provide the added protection of nitrile over latex, but are more expensive
than latex.  Third, cheap latex gloves.  These are used only once and then
disposed of.  They protect the nitrile.  I reuse the nitrile gloves dozens
of times since they are more expensive.  I have found no problem with
sensitivity while doing a lay up.  Working with squeeges, paint brushes,
mixing sticks & cups, not much sensitivity is really needed.

>But, we can avoid  the use of
>solvents when it comes to brushes.  Again, "cheap" is the common
denominator
>here and Harbor Freight sells 2" wide "chip brushes" for about $12 / box of
>36.   Use them once and throw it away.   I know what many of your are going
>to say - "They tend to shed hairs into your lay-up".   Yes they do, and
"you
>get what you pay for" pertains here too.

I keep a small bottle of thin CA glue (Hot Stuff, Jet, Super Glue, etc.)
nearby and run it along the bristles where they enter the ferrule.  The thin
glue wicks right into the bristles and glue them to one another.  It doesn't
take much, a 1 oz bottle goes a long way and no more lost bristles.  If you
soak your brushes in acetone between lay ups, like I do, you have to reapply
the CA as it will be dissolved by the solvent.  Just make sure all the
solvent has evaporated before applying the glue.

>BUT, I have found that if you cut
>off about half the length of the brush hairs, the loose hairs will "fly
out"
>out of the brush more easily and completely when you "flick" it over your
>hand, the corner of the bench top, or the sticky side of a piece duct tape.
>Another good reason for cutting the brush
>hairs short is that it improves "stroking" and "stippling" performance of
>the brush considerably.

Have not tried cutting them, but sounds like a good idea.  Will try it on my
next lay up.


My $.02 worth.

Russ Fisher


Date: Mon, 23 Aug 1999 22:29:03 -0400
From: bil kleb <kleb@geocities.com>
Subject: Re: COZY: RE: Oshkosh Forum / RUBBER GLOVES

Russ Fisher wrote:
> I use a triple layer:  First, a cotten liner [...] Second, the thin nitrile
> gloves [...] Third, cheap latex gloves. [...]

that's exactly the recipe i've been using.  i get the materials from
lab safety (http://www.labsafety.com/ or 800 356-0783).  they recently
split their 1900+ page catalog into 7 bits.  they also have tech reps
available for consulting.

-- 
bil <http://www.geocities.com/~kleb/>

From: "John Slade" <rjslade@bellsouth.net>
Subject: Re: COZY: RUBBER GLOVES & BRUSHES
Date: Mon, 23 Aug 1999 20:53:10 -0400


>I use a triple layer:  First, a cotten liner - relatively inexpensive...

I use one layer of latex with my MGS epoxy.  I'm in Chap 14 and have had no
allergy problems so far.

>If you soak your brushes in acetone between lay ups...
I never use the same brush twice. During large layups I often go through 3
or 4 brushes. I've probably spent $15 on brushes so far. By the time the
plane is finished my "brush budget" might hit $30. Is it worth the trouble
and possible problems of solvent in the next layup?

My 2c
John Slade
Cozy #757

From: "Russ Fisher" <rfisher1@rochester.rr.com>
Subject: Re: COZY: RUBBER GLOVES & BRUSHES
Date: Tue, 24 Aug 1999 00:33:55 -0400

John,

>I use one layer of latex with my MGS epoxy.  I'm in Chap 14 and have had no
>allergy problems so far.

I am very glad to hear that.  However, why can one person build three
airplanes using only barrier cream and have no problems, yet another will
develop a reaction after only a few lay ups using gloves?  Because we are
all different with very wide-ranging sensitization levels.  What works for
you does not necessarily work for everyone.  Unfortunately, none of us knows
our own sensitization level.  I therefore have chosen to be as careful as I
can.

>I never use the same brush twice. During large layups I often go through 3
>or 4 brushes. I've probably spent $15 on brushes so far. By the time the
>plane is finished my "brush budget" might hit $30. Is it worth the trouble
>and possible problems of solvent in the next layup?


I suppose it depends upon your definition of trouble.  Pull the brush out of
the jar of acetone and shake it out - 5 seconds.  By the time I have my
gloves on the brush is dry - acetone evaporates VERY fast.  Squirt some CA
glue on the bristles - 5 seconds.  By the time I mix my first batch of resin
the CA is cured.  After lay up, wipe brush and put back in acetone - 5
seconds.  I think I can afford 15 seconds per lay up to save a brush and a
little space in the land fill (of which I'm using more than my share
building this airplane).  On very large lay ups, the resin starts to cure in
the brush, so yes, I must discard it.  But I can do MANY small lay ups
before a brush gets too flat to be usable.

See ya,

Russ Fisher


Date: Mon, 23 Aug 1999 23:21:25 -0700
From: Martin Orro <martin@orro.net>
Subject: Re: COZY: RUBBER GLOVES & BRUSHES

Cotton liners are an excellent procedure.  In dentistry, I wear gloves 6
to 8 hours a day, changing them every 15 minutes but sometimes for an
hour or more during long procedures.  The problems mentioned are
minimized by the cotton liners.  Sensitivities are caused by:

	1- "impure latex"-  proteins bound in the latex matrix 
	2- porosity's- testing in our offices has shown >60% of the gloves
sampled leak 		water.  (Fill like a water balloon and hang for a few
hours over a dry 		surface.)  Very few manufacturers (<30%) have decent
quality control.
	3- powder- talc is the least problematic.  Many gloves utilize
cornstarch - bad juju 		many organisms thrive in sweat and starch -
besides it makes your hands stink
	4- prickly heat rash- sweat glands become plugged and breed beasties
which cause a 		prickly burning sensation with attendant spotted rash.
	5- bad hygiene- wash em before putting on the gloves, avoid petrolatum
based hand 		lotions (screws up the latex) and keep the powder out of
your eyes 		(conjunctivitis is painful)

martin orro

From: "John Slade" <rjslade@bellsouth.net>
Subject: Re: COZY: RUBBER GLOVES & BRUSHES
Date: Tue, 24 Aug 1999 10:24:22 -0400

Russ,

>>I use one layer of latex with my MGS epoxy.  I'm in Chap 14 and have had
no
>>allergy problems so far.

>Unfortunately, none of us knows our own sensitization level.

Agreed. I've been following comments on this issue very carefully. Certainly
there is risk. I met one guy who had to give up epoxy building half way
through his project.  His skin was in very bad shape. I've met others who
have never experienced a problem after using epoxy for long periods without
protection. I suspect that the problem is much worse with some epoxy types
than it is with others.

I am left with the question "What is the level of the risk?"  Statistically
how many people develop sensitivity to which epoxy type after how long? I've
seen no studies of this nature and I need this information in order to make
an informed decision. Everything we do has risk associated with it.  As
pilots we avoid high risk situations, but accept "low risk" situations (like
driving to the airport).  We tread the path between the two very carefully
using "all available information". My concern here is simply that
[relatively unimportant] decisions are being made based on insufficient
information. In this forum I've occasionally seen issues get way out of
proportion (like the 2.5 inch spar tape for example). I'm wondering if this
problem has been hyped out of proportion to the risk involved. Yes, the
safest course is to wear 3 pairs of gloves at all times, use protective gel
on all other exposed areas of the body and to scrub afterwards - that way we
dont have to care about the statistics. But, if we use this logic in
everything we do the natural conclusion is that we all need NASA space suits
to go outside at all.

Just trying to get some perspective.

John Slade
Cozy #757


Date: Tue, 24 Aug 1999 13:05:02 -0400
From: bil kleb <kleb@geocities.com>
Subject: Re: COZY: RUBBER GLOVES & BRUSHES

John Slade wrote:
> 
> Just trying to get some perspective.

my perspective is simple: i've had a dream to build one of these planes
for over 15 years.  i don't want to throw the dream away on some (easily)
avoidable epoxy allergy.

-- 
bil <http://www.geocities.com/~kleb/>

From: "Frank Johanson" <ics@ime.net>
Subject: Re: COZY: RUBBER GLOVES & BRUSHES
Date: Tue, 24 Aug 1999 23:29:38 -0400

Hi John
as I have said before I work in a full suit all the time , with pumped in
fresh air .  if you are interested I will give you details on how to get it
and what to do to set it up. I did it for under a hundred bucks.

frank


Date: Tue, 28 Sep 1999 08:23:57 -0400
From: Paul Krasa <p.w.krasa@larc.nasa.gov>
Subject: Re: COZY: hexcell

You can buy 5 min. epoxy in your local hardware store in convenient double
barrel syringe containers.


Paul
Long EZ 214LP


At 21:23 9/27/99 -0500, Nat Puffer wrote:
>Dear Dewayne,
>The 9935 epoxy is 5-minute epoxy used only for tacking things together
>temporarily. You could substitute 3-minute, 4-minute, 6-minute, hot-stuff,
>or almost anything that would serve that need.
>Regards,
>Nat
>
>----------
>> From: dewayne morgan <dmorgan@mis.net>
>> To: cozy_builders@canard.com
>> Subject: COZY: hexcell
>> Date: Monday, September 27, 1999 10:20 PM
>> 
>> Could you please re-send your messages. my microsoft mail program crashed
>> when it downloadedthe mail
>> 
>> thanks 
>> 
>> (reason number 10,001 to use linux)
>> 
>> 
>> In the plans it calls for epoxy (9935 from wick's) . I have looked for
>this
>> and can not seem to find it. Is there a replacement/substitute for this ?
>> 
>> (Just tryin to build it exactly to plans)
>> 
>> dewayne
>> 
>
>

From: "John Slade" <jslade@adelphia.net>
Subject: COZY: Chap 4 - MGS epoxy won't harden
Date: Sat, 6 Mar 1999 21:13:06 -0500

I'm using MGS 335 epoxy with the slow hardner.
I tried a test layup 2 days ago and it's still not hard. Today I tried
another test and left the remaining epoxy in the cup. 12 hours later the
layup is still tacky and the epoxy in the cup is still mobile. ie I can
still move the tongue depresser in it and depress the surface with my
finger.  Temperature has ranged between 62 and 75 during this period. The
epoxy is kept in a HOT box. I measured the temp in there and found it was
106f. Tomorrow I'm going to try the "fast" hardner and lower the temp in the
hot box to about 85.

Anyone have any suggestions or ideas?
Is the MGS rep who helped out a week or two ago reading this mail list?
Anyone have his email address?

I haven't done a "real" layup yet. If the epoxy doesnt cure the part is
ruined. - right?
John Slade (#757)

