Date: Wed, 7 Jan 1998 20:38:56 -0600 (CST) From: cdenk@ix.netcom.com Subject: COZY: Epolite 2427 Caution Finally got to the bottom of the 2427 epoxy thats about 3 years old. Note that I have been using it for none critical items, the last was a new instrument panel cover. Although it appeared to cure properly, and the hardner is obvious where excess moisture got a it, I was very suprised to find a half inch of a gell with some crystals in the bottom of the resin pump container. From the outside looking thru the opaque container, and a quick look from the top, nothing looked wrong. Caution - check the bottom of the container for this goop. Date: Thu, 08 Jan 1998 07:50:04 -0500 From: bil kleb Subject: Re: COZY: Epolite 2427 Caution cdenk@ix.netcom.com wrote: > > Finally got to the bottom of the 2427 epoxy ... > I was very suprised to find a half inch of a gell with > some crystals in the bottom of the resin pump container. did you store it at temps less than, say, 60 F? if so, this sounds similar to what happens to ez poxy. from the archives, last feb via jeff r: : I have had a lot of calls about clumpy hardener : over the past weeks and cold weather is taking : it's toll. : People who are using the Safe-t-poxy (EZ10/ EZ84) : should store your hardener at or above 60 degrees. : (up to 150 degrees) : If you don't, the hardener can and will start to : crystalize and thicken. It will go back to normal : if you warm the container in warm to hot water. : This will in no way hurt or change this resin system : if it has ever crystalized. JUST KEEP IT WARM!! -- bil Date: Mon, 02 Feb 1998 21:04:22 -0800 From: Wayne Lanza Subject: Re: COZY: Epoxy Pump Cleaning Ed Harasimowitz wrote: > > >Epoxy pumps, over time, tend to gum up and require periodic > maintenance. > >I have used warm to hot soapy water and did a lot of scrubbing to get > >all the parts clean. Is there an easier way to clean these pumps? What > >solvents can cut the resin and hardener? I would appreciate any info on > > >the subject. Thanks. A "GUMMED-UP" epoxy pump is no fun to clean. Infrequent use, I'm ashamed to admit, has made this a repeated chore for me. I start out by emptying both containers into separate cans. Keep the old resin for non-structural stuff if there's enough to worry about. Next I carefully heat the pump metering block assembly with a heat gun or small electric space heater. Needless to say, DON'T use any violent heat sources like a tourch or really hot heat gun! The object is to heat the block & not melt the tanks. If you're worried about getting the tanks too hot, leave the resin in them to keep them cooler. The dispensing tubes are a real bummer to clean out too, just get them real warm & clean them out with long pipe cleaners from a craft shop or shove/pull something thru them with safety wire. Oh yeah... back to the pump block, once it has been warmed up some resin will/may run out of the dispensing tube fittings (if the tubes have been removed). At this point you can start to work the pump a little. Wipe out most of the junk in the tanks and pour about a cup of acetone in them AFTER YOU'VE REMOVED THE HEAT SOURCE!! It's a good idea to have the dispensing tubes back on the pump at this time, I think you can figure out why... Proceed to work the pump slowly until you get a good even flow from both sides. This may be long winded, but I've had a seriously seized pump twice over the years and this method works pretty good. May your pump not be as bad as mine was, Wayne Lanza From: Marc J. Zeitlin Subject: Re: COZY: Epoxy Pump Cleaning (fwd) Date: Wed, 4 Feb 98 8:40:47 EST >Ed Harasimowitz wrote: >> >I have used warm to hot soapy water and did a lot of scrubbing to get >> >all the parts clean. Is there an easier way to clean these pumps? What >> >solvents can cut the resin and hardener? Wayne Lanza explained his method, which sounds like it would work well. I described how I cleaned my pump last year - it should be in the archives. Basically, I took it apart completely and cleaned all the parts with alcohol. Took about an hour, and worked well - they pump had been pretty gummed up, and now is very smooth. -- Marc J. Zeitlin Email: marcz@an.hp.com Date: Wed, 04 Feb 1998 20:35:10 +0000 From: David Domeier Subject: Re: COZY: Epoxy Pump Cleaning Ed, I switched epoxy systems midway in my MKIV and found it easiest to buy a new plastic tank and gaskets. Cleaning the metal pump parts was simple with acetate. dd From: Bes1612@aol.com Date: Wed, 11 Feb 1998 12:13:04 EST Subject: COZY: old hardener I'm getting kind of ticked off at Aircraft Spruce. I had to wait a couple of weeks to get enough 3 inch uni tape for my final spar cap on the left main wing. And what I had gotten befor was like left over stuff, riminants of rolls that were tangled and I had to work at getting them straight. I did not realize how much untill the last order finally arived and this stuff was straight! To really make my day, the 5 gal kit of epoxy I ordered was a full year old, according to the date on the can. The hardener had gone bad and I did not find out untill well into my wing layup! I took what I needed to finish the layer of uni I was on, heated it up and got it workable, then peal plyed the whole thing. I'm wondering if this stuff will set up alright? I laied up the two plys of uni on the surface, last night. its been pretty cool, so I dont expect it to be really set for a couple of days. And I only used about a pint of mixed epoxy with the bad hardener, just to finish that ply. What do you think? I'm going to send back this stuff, but what I had to use, has it ruined my layup? Bob Smith From: Marc J. Zeitlin Subject: COZY: old hardener (fwd) Date: Wed, 11 Feb 98 13:36:47 EST Bob Smith wrote: >I'm getting kind of ticked off at Aircraft Spruce........ Give them a call and talk to their customer support - it's been getting better lately. If they don't give you what you're looking for, talk directly to Jim Irwin (president and owner). He's a pretty reasonable guy. >........ The hardener had gone bad......... >....... I'm wondering if this stuff will set up alright?........ >..... I'm going to send back this stuff, but what I had >to use, has it ruined my layup? There were some discussions regarding epoxy aging in the archives - probably some in each of the past three years worth. After a long time, especially if it get cold, the hardener can crystallize. Warming it as you did will re-liquify it and make it usable again. In my experience, this does not affect the properties of the epoxy - it has always cured properly for me, even after having been totally crystallized and re-warmed. Wait a few days and do the "scratch" test as described in the plans. If you get a clean scratch, you've got a good layup, epoxy-wise. You didn't mention which epoxy you're using - my experience has been with Safety-Poxy, 2427, and EZ10/84 (equivalent to SPII, I believe). -- Marc J. Zeitlin Email: marcz@an.hp.com Date: Wed, 18 Feb 1998 19:47:32 -0500 From: bil kleb Subject: COZY: yet more epoxy info [long] while looking for the red hook brewery in seattle last week, i ran across system three resins---the people who make the water-reduceable polyurethane paints, general boat building epoxies similar to west system from gougeon brothers (http://www.gougeon.com/), and most probably the five-minute epoxy you have in your workshop. anyway, while asking directions i picked up their assorted brochures. of particular interest has been their "the epoxy book" (see http://www.systemthree.com/). besides a decent basic chemistry lesson, it includes such gems as: o much acetone sold today is reclaimed and may have impurities that interfere with secondary bonding by leaving a film of residue on the surface. (i.e., get $technical$ grade chemicals and stop wiping with acetone before a secondary layup?) o epoxy resins may be applied over cured polyesters that have been dewaxed and well sanded but polyesters should never be used over cured epoxy resins. unreacted amine [throughout] the epoxy inhibits the peroxide catalyst in the polyester causing an incomplete cure at the interface. sanding does NOT get rid of the unreacted amine. the result is a poor bond even though the surface appears cured. debonding will be the inevitable result. (i.e., don't use polyester body fillers over epoxy.) o haziness and crystallization [of the resin] will occur if stored at cold temperatures (below 50F) for prolonged periods. immersing the closed container in hot tap water and heating to 120F or above will bring the resin back to a clear state. neither crystallization nor heating will adversely affect the product. o since all epoxy based materials eventually chalk in sunlight be careful when using the two part epoxy paints for exterior finish coats. (i.e., use epoxy only for primer coats?) o don't pot stainless steel bolts in epoxy resin. stainless steel works only in the presence of sufficient oxygen. note: the msds's for system three resin, ez-10 resin, 2727 resin, and 2410 resin indicate that they are all based on the same chemical compound, CAS 25068-38-6. -- bil From: Lee Devlin Subject: COZY: Polyester fillers over epoxy Date: Fri, 20 Feb 98 11:14:29 MST bil wrote: > o epoxy resins may be applied over cured polyesters that have been > dewaxed and well sanded but polyesters should never be used over > cured epoxy resins. unreacted amine [throughout] the epoxy > inhibits the peroxide catalyst in the polyester causing an > incomplete cure at the interface. sanding does NOT get rid of > the unreacted amine. the result is a poor bond even though the > surface appears cured. debonding will be the inevitable result. > (i.e., don't use polyester body fillers over epoxy.) Thanks bil, for the first potential explanation I've seen as to why some people have had so much trouble with polyesters and others, apparently, do not. It makes me wonder it it is possible to 'seal up' the unreacted amine with a coat of epoxy primer. I know that it is acceptable to put polyester filler over epoxy primer as that is the recommended method to coat bare metal prior to applying the polyester filler in the automotive world. Maybe there's more to this subject than just saying 'no' to polyester fillers. Lee Devlin N36MX http://members.aol.com/lee810 From: "Jason Holifield" Subject: COZY: Epoxy which one? Date: Sun, 22 Feb 1998 19:23:42 -0600 I have not recieved my plans yet so this is an uneducated question. The parts list I downloaded from Marc's website calles for RAE or Safe-T-Poxy. I was wondering if there was any reason not to use Poly Epoxy by Poly - Fiber? Perhaps this is a dumb question that will be answered when I get my plans. Any info on the subject would be great. Thanks Jason Holifield From: Marc J. Zeitlin Subject: COZY: Epoxy which one? (fwd) Date: Mon, 23 Feb 98 9:53:23 EST Jason Holifield wrote: >I have not recieved my plans yet so this is an uneducated question. The >parts list I downloaded from Marc's website calles for RAE or Safe-T-Poxy. I >was wondering if there was any reason not to use Poly Epoxy by Poly - Fiber? You will get the list of approved epoxies in the plans and newsletters. There are other epoxies that people use as well (don't know which category Poly Epoxy falls into off the top of my head) however they have either not been approved by RAF/Nat or have not been tested by RAF/Nat. Approval, however, is no guarantee - many people had some problems with 2427, which was approved for a while and then removed from the approved list. See the archives for 1995, 1996, 1997, and this year for an almost mind-numbing load of information regarding different epoxies. -- Marc J. Zeitlin Email: marcz@an.hp.com Date: Mon, 23 Feb 1998 07:18:54 -0500 From: "Jeff S. Russell http://www.AeroCad.com" Subject: Re: COZY: Epoxy which one? Jason Holifield wrote: > > I have not recieved my plans yet so this is an uneducated question. The > parts list I downloaded from Marc's website calles for RAE or Safe-T-Poxy. I > was wondering if there was any reason not to use Poly Epoxy by Poly - Fiber? > Perhaps this is a dumb question that will be answered when I get my plans. Jason, It will work just as good as the RAE but only has one gel time where the RAE you can get fast or slow. It also has no tint and I think tint is better to see problems in a layup. EZ-poxy (Safe-T-Poxy) has stryene and will smell like bondo. The trade off for the smell is better workabilty in high humidity and plenty of tint. -- Jeff Russell/AeroCad Inc. E-mail: Jeff@aerocad.com P.O. Box 7307 Port St. Lucie FL. 34985 Shop# 561-460-8020 Home# 561-343-7366 Composite workshop info: http://www.Sportair.com Date: Mon, 23 Feb 1998 09:44:24 -0600 From: Darren DeLoach Subject: Re: COZY: Epoxy which one? At 07:23 PM 2/22/98 -0600, you wrote: >I have not recieved my plans yet so this is an uneducated question. The >parts list I downloaded from Marc's website calles for RAE or Safe-T-Poxy. I >was wondering if there was any reason not to use Poly Epoxy by Poly - Fiber? I did a lot of research into epoxies just before I started. Poly Epoxy was one that I considered seriously; it's the one used at the Alexander SportAir clinics so I knew what its workability was (one should note that the reason it's used in the workshops is that Ron Alexander is part owner of PolyFiber and wants them to use his epoxy, OTOH he had to pick something and this epoxy worked great in the class, with not too bad a smell, worked into the glass well and overall seemed an easy to use epoxy). PolyFiber is on-line, call the 800 number and they'll give you the MSDS and technical docs you would need to make a decision (they sent them to me). There's a good chance you could have a semi-local dealer willing to give you a price break (there was one near me). In the end, I chose NOT to use Poly Epoxy, for some pretty nontechnical reasons: -- I'm NOT an experienced builder, nor a materials engineer, and so I'm not inclined to be "overly" experimental. This epoxy is new enough that it is essentially untested, in the sense that there aren't thousands of aircraft flying out there with it like the older epoxies, which you'd have to say have stood the test of time. -- Nat says don't use it (I called him), neither he nor Rutan AF have approved it for EZ aircraft. -- Rutan AF says that since they aren't in the plans business anymore, they also aren't approving any new materials anymore, as they don't do this sort of testing now (I called them to ask). -- I live in a humid climate, and it wasn't clear to me that PolyEpoxy was a good candidate in highly humid conditions. (I'm not saying it isn't, it just wasn't clear to me at the time I had to choose). Note that nobody says it WON'T work great, it's just that nobody (in the EZ world) had tested it enough to put a stamp of approval on it. One might argue that since Nat hasn't approved it, your use of it might mean that Nat might request you not register your aircraft as a Cozy Mark IV, since changing epoxies is a kind of deviation from the plans, but this sort of logic is distasteful and if that were the case I'd like to see Nat do the proper testing and approve or disapprove based on the merits of the stuff. More competition among epoxy vendors would be good for builders, and PolyEpoxy is easily available. You don't have to build an entire airplane to do proper testing of the substance; either its basic properties are in the realm of the approved ones or not, and a public declaration would remove any confusion on the issue. Personally, my gut feeling was that it was probably fine to use, but I'm not ready to bet my life on it yet __given my particular circumstances__, so I went with EZPoxy (newer name of Saf T Poxy) which was both approved and works well in humid climates. OTOH, if PolyEpoxy had been approved, I would certainly have given it serious consideration. The part we made in the class certainly seems as strong to me as the ones I have made with EZPoxy. -- Darren DeLoach http://www.deloach.com Chap. 6 From: ponciroli@postoffice.worldnet.att.net Date: Mon, 23 Feb 1998 09:18:05 -0500 Subject: Re: COZY: Epoxy which one? Jason Holifield wrote "I have not received my plans yet so this is an uneducated question. The parts list I downloaded from Marc's website calles for RAE or Safe-T-Poxy. I was wondering if there was any reason not to use Poly Epoxy by Poly - Fiber?" Jason - I used Poly epoxy for a while but it, like most of the others, gave me a skin reaction. The epoxy that I find the most agreeable to work with is Aeropoxy. It is approved by Nat and it works well. Poly epoxy also works well, but is not on the approved epoxy list as far as I can discern. As an aside, the Poly Epoxy literature calls for a post cure. They say it up front. Most other manufacturers do not mention it as conspicuously, However, all epoxys require a post cure to be fully cured. That requires that the ambient temperature be raised to between 140 - 170 degrees. This can be done by building a small tent that is insulated. The heaters should be monitored for about two hours to get the proper cure. The parts to be cured should be well supported so that they do not lose their tolerances. Now, that being said, I would conjecture that most of the glass airplanes that are flown today have not been fully post cured, at least not intentionally. This should stir up the hornets. Don Ponciroli ponciroli@att.net Date: Mon, 23 Feb 98 15:25:41 EST From: "Nick J Ugolini" Subject: Re: COZY: Epoxy which one? Jeff R. wrote: Jason, It will work just as good as the RAE but only has one gel time where the RAE you can get fast or slow. It also has no tint and I think tint is better to see problems in a layup. EZ-poxy (Safe-T-Poxy) has styrene and will smell like bondo. The trade off for the smell is better workability in high humidity and plenty of tint.<< I have used the 2427 (no problems) the West System epoxies and the EZ-poxy. I think the workability of West and EZ-pozy is about the same. West has much less smell and wets out just a easier than EZ. I like West a lot, but the strength numbers are higher for EZ than for West and the cost is the same. I have heard guy complain allot about sanding micro and couldn't figure why they were moaning about it (I was using West). I will tell you this, West sands MUCH easier than EZ. I couldn't believe the difference. Maybe EZ is stronger? My personal choice would be to build with EZ and finish (micro) with the West. From: Marc J. Zeitlin Subject: Re: COZY: Epoxy which one? (fwd) Date: Mon, 23 Feb 98 16:12:55 EST Nick Ugolini wrote: >I have used the 2427 (no problems) the West System epoxies and the EZ-poxy. >I have heard guy complain allot about sanding micro and couldn't figure why >they were moaning about it (I was using West). I will tell you this, West >sands MUCH easier than EZ. I couldn't believe the difference. Maybe EZ >is stronger? My personal choice would be to build with EZ and finish >(micro) with the West. I know that this has been discussed before, but the WEST system epoxy is NOT recommended for laminating - only for finishing. Yes, it sands a lot easier, and yes, it's great for finishing, but for whatever reason (strength, UV resistance, I have no clue) it should not be used for layups. I believe that this is covered in the plans or newsletters somewhere. I've also heard it from many knowledgeable EZ builders. -- Marc J. Zeitlin Email: marcz@an.hp.com From: "Fred I. Mahan" Subject: COZY: Epoxy which one? Date: Mon, 23 Feb 1998 16:19:05 -0500 Nick J Ugolini said: > My personal choice would be to build with EZ and finish > (micro) with the West. This is what most canard scratch builders I know have done, and what I will do on my next project. Fred in Florida Long-EZ N86LE Defiant project #137 Date: Tue, 24 Feb 1998 09:43:57 -0500 From: Paul Krasa Subject: Re: COZY: Epoxy which one? snip > >This is what most canard scratch builders I know have done, and what I will >do on my next project. > >Fred in Florida >Long-EZ N86LE >Defiant project #137 > > Ditto!!! Stick with the tried and true combination as Fred states, and you will limit your problems. This is not an area to recreate the wheel. This subject is covered very throughly in the archives, and the problems others have encountered with other epoxies. Paul Krasa Long EZ 214LP Date: Tue, 24 Feb 1998 09:10:05 -0800 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: Re: COZY: Epoxy which one? (fwd) >I know that this has been discussed before, but the WEST system epoxy is >NOT recommended for laminating - only for finishing. Yes, it sands a lot >easier, and yes, it's great for finishing, but for whatever reason >(strength, UV resistance, I have no clue) it should not be used for >layups. I believe that this is covered in the plans or newsletters >somewhere. I've also heard it from many knowledgeable EZ builders. > >-- >Marc J. Zeitlin Email: marcz@an.hp.com Agreed, Marc. Perhaps the most knowledgeable EZ builders I heard it from were Burt Rutan and Mike Melville. I was at one of their "shindigs" at Mojave where one of the flyin attendees suffered some nose gear damage upon arrival. Mike helped him get the thing temporarily fixed, so he could fly home. They used West systems and heat lamps to speed the process, but Burt and Mike stressed that this was for ferrying home ONLY, and that West just did not have the required characteristics for aircraft-style lamination, and should never be used for building primary structure. --Howard Rogers, A&P 2005148 Date: Tue, 24 Feb 1998 10:44:42 +0200 From: Rego Burger Subject: COZY: Laminating vs finishing resin. Laminating resins are stiffer than finishing resins, hence providing a higher, strength / flex ratio. Finishing resins the total opposite their flex /strength ratio is higher. This means the elongation to break is greater on finishing resins. On a large surface like a wing there is a reasonable amount of flexing in turbulence and during manouvering. If you finish the micro fill with a laminating resin you "can" find, with time, cracks appearing on the surface. So you can get away with using your left over laminating resin and micro to fill weave and imperfections on the stiff fuselage but be weary of using it on the canard and wings, the WEST finishing resins are more flexible and do sand easier to some extent. ( West do make laminating resins... Pro Set 125 is one of them .) Also with finishing if you make the DRY micro TOO DRY ie. excessive micro vs resin you're back in the same boat...cracking! Micro is a glass sphere (bubble) glass cracks, the resin does not fill the bubble unless it breaks during mixing. Too little resin ( over dry ) and you could get surface cracks. What some folks do after that LAST sanding is to paint a thin..thin layer of slurry ( west )over the surface to help "seal" the final coat prior to primming. The added weight is marginal compared to the extra weight put on in a respray in 5 years time to repair cracks. Rego Burger, web site: http://home.intekom.com/glen/rnb.htm (home e-mail) mailto:rnb@intekom.co.za From: cdenk@ix.netcom.com Date: Tue, 24 Feb 1998 20:42:42 -0600 (CST) Subject: Re: COZY: Laminating vs finishing resin. Remember leading edges should have no micro, but filled with flox. The micro will flake in time from bug impacts. With 550 hours including some heavy rain, snow I have zero chips in the leading edges. Date: Tue, 03 Mar 1998 06:21:55 +0200 From: Rego Burger Subject: COZY: Fuel Resistant Foams + Resins Did the same ditto! Also just did some layups with 2427 of the same age, the hardner is the same etc. It still cures on time. Scratch tests fine sands fine looks fine after a year in the can. Although this is not a good practise it's nice to know that the resin ( batch I have ) is OK. It seems the stuff could be like wine, getting better with age..:-) Rego Burger, web site: http://home.intekom.com/glen/rnb.htm (home e-mail) mailto:rnb@intekom.co.za RSA >>> ok How 2/March/1998 07:55pm >>> I placed samples of glass layup and fuel tank foam in a mason jar filled with fuel. Replaced the fuel once with auto fuel known to contain alchohol. Foam not affected. Epolite 2427 not affected. Samples have been immersed for over a year now. I have no concerns. Rumors regarding 2427 fuel compatability totally unfounded. quote from -al wick Date: Tue, 03 Mar 1998 08:53:01 -0800 From: Eric Westland Subject: Re: COZY: Fuel Resistant Foams ok How wrote: > I placed samples of glass layup and fuel tank foam in a mason jar filled > with fuel. Replaced the fuel once with auto fuel known to contain > alchohol. Foam not affected. Epolite 2427 not affected. Samples have been > immersed for over a year now. I have no concerns. Rumors regarding 2427 > fuel compatability totally unfounded. These rumors were of concern to me as well since my strakes are constructed of 2427, so I started my own tests. I laid up some samples with some old, cloudy 2427 that had been sitting idle in my pump for at least 6 months while I sanded. They cured fine. In addition, I rounded up some leftovers from construction including some strake baffle samples (H45 foam) and some turtleback samples which have the Clark substitute foam. I then weighed these samples on two different Ohaus scales at the high school I teach at which read to the nearest 0.001 gram and also weighed a CD-ROM as a reference. Then I plopped them all in either 100LL or mogas (except for the CD-ROM) and shook them every few weeks. It's been a year now and they all are just fine. There has been no weight loss (epoxy dissolved away) and the foam appears to be just fine. If anything, there has been a slight (<1%) weight gain on the mogas samples. Since I have not changed the fuel itself except once, a light varnish-type coating may be adding the slight weight, although I can't see one. I'd be interested in anyone's ideas on how to improve my testing. They all still scratch hard and white. Eric Westland Date: Thu, 12 Mar 1998 14:37:19 +1000 From: Allan Aaron Subject: COZY: Epoxy Hi folks, Having not touched my project for several months I recently did four or five glass lay ups over a period of about a week. I always test the epoxy residue (I'm still using 2427) and while the first couple of lay ups passed the scratch test well the last few seem a little gummy (with some bubbling/frothing at the surface). I threw out the old epoxy/hardener and replaced it with a new batch straight from the cans, did another mix and left a few cups out to set. It still didn't set quite right. I believe that the temperature and humidity are ok (75 degrees/65%) and the epoxy sits in a heated cabinet (to about 85 degrees). I've recently changed mixing cups from the ones supplied by Wicks and have tried both uncoated paper cups (which appear to absorb some of the epoxy) as well as coated paper cups. The epoxy is probably somewhat out of shelf life (its about 1-1/2 to 2 years old I suppose). Any ideas what might be wrong? (a) blockage in the epoxy pump causing inaccurate ratio? (b) epoxy past its shelf life? (c) wrong paper cups? (d) any other thoughts????? Thanks Date: Thu, 12 Mar 1998 07:30:11 +0200 From: Rego Burger Subject: COZY: Epoxy In response to "allana@interconnect.com.au" I use a balance so I get no pump blockages....I just mixed some that have been in the can for 2yrs+ and they all set OK, however compared to all the other resin systems I've used I find 2427 takes longer to cure. >From my experience it takes about 48hrs to set dry without heat treatment, and a further 14 days to become fully cured / rigid..... until then it is fairly flexible. Oh! I never pull off peel ply before 30hrs (unheated)or else it is gummy. So I think ....correction I KNOW it is a SLOW system. I have mixed as little as 20ml batches at a time on my home-made scale with good results. If you're in a hurry use heat to speed up the cure time. I place light-weight plastic bags over objects to keep off the lay-up surface....point in a fan heater and blow warm air into the "tunnel" this works fine and also gets rig of any humidity problems over the part! Good luck! Rego Burger, web site: http://home.intekom.com/glen/rnb.htm (home e-mail) mailto:rnb@intekom.co.za RSA From: "Paul Comte" Subject: Re: COZY: Epoxy Date: Thu, 12 Mar 1998 09:37:37 -0600 -----Original Message----- From: Allan Aaron To: Cozy Builders Date: Wednesday, March 11, 1998 9:42 PM Subject: COZY: Epoxy >Hi folks, snip > I've recently >changed mixing cups from the ones supplied by Wicks >and have tried both uncoated paper cups (which appear to absorb some of >the epoxy) as well as coated paper cups. The epoxy is probably somewhat >out of shelf life (its about 1-1/2 to 2 years old I suppose). > >Any ideas what might be wrong? > >(a) blockage in the epoxy pump causing inaccurate ratio? >(b) epoxy past its shelf life? >(c) wrong paper cups? >(d) any other thoughts????? > Weight the two components on an acurate scale. Then you know you have a working pump. Make two samples, one each in the two types of cups. Your cup may have leeched the ratio. Post cure? Do you have the time. Or, if you are handy with money, when in doubt - throw it out (to your local marine dealer...) >Thanks > > > From: Lee Devlin Subject: COZY: Cleaning out the epoxy pump Date: Tue, 17 Mar 98 8:54:26 MST I posted this message on the canard aviators list and I realize that not all of you are members of that list so I decided to post it here too. I wanted to clean out my Michael Engineering epoxy pump and was wondering which parts I will need. It's obvious I would like to replace the plastic containers and the seals. In looking through the AC Spruce catalog, there is a 'rebuild kit', but it doesn't say what's in it. The Wick's catalog has no rebuild kit but instead has 3 separate containers, 1/2" and 3/4" teflon seals, intake valve, intake valve washer and gasket as well as the tubes with compression fittings (all of which are all available separately.) I think that the metal parts can be soaked in MEK but without taking the pump apart first, it's hard to know which seals and gaskets are required. It appears that both pistons are 3/4". I may also elect to make it switchable from 44:100 to 25:100 ratios which should be relatively easy as it has separate blocks for each bin. If someone has done this recently, please let me know which parts are essential. Thanks, Lee Devlin LongEZ 36MX http://members.aol.com/lee810 From: Marc J. Zeitlin Subject: COZY: Cleaning out the epoxy pump Date: Tue, 17 Mar 98 11:27:40 EST Lee Devlin wrote: >I wanted to clean out my Michael Engineering epoxy pump and was >wondering which parts I will need. It's obvious I would like to replace >the plastic containers and the seals..... >I think that the metal parts can be soaked in MEK......... Geez, Lee, we had this discussion of pump cleaning a while back - did you check the archives? :-). A few people (myself included) posted their methods of cleaning their pumps. To summarize my own method, I cleaned every last part (except for the plunger grease) off with alcohol. Worked great - didn't have to replace anything. -- Marc J. Zeitlin Email: marcz@an.hp.com From: John Ellor Subject: COZY: Re: Cleaning out the epoxy pump Date: Tue, 17 Mar 1998 11:33:39 -0500 Lee Devlin wrote: >>I wanted to clean out my Michael Engineering epoxy pump and was wondering which parts I will need. It's obvious I would like to replace the plastic containers and the seals. In looking through the AC Spruce catalog, there is a 'rebuild kit', but it doesn't say what's in it. The Wick's catalog has no rebuild kit but instead has 3 separate containers, 1/2" and 3/4" teflon seals, intake valve, intake valve washer and gasket as well as the tubes with compression fittings (all of which are all available separately.)>> Lee, I got my parts direct from Michael Engineering, you could give them a call for parts and prices. I had to clean out my pump last year, it was jammed solid. I replaced the tanks and also had to replace one of the fine springs which are in the output ball valves. If yours is crystalized in there the spring will likely be destroyed when you disassemble the valve, thats what happened to me. Seals seem to be tough, mine survived even though I eventually had to resort to pounding the pistons free with a rod and hammer (ouch). Note Soaking in MEK didn't have much effect on a seized pump. Regards John Ellor (Mk3 #283) Date: Tue, 17 Mar 1998 21:43:43 -0800 From: George Krosse Subject: Re: COZY: Re: Cleaning out the epoxy pump John Ellor wrote: > > Lee Devlin wrote: Snipped by George Using the west system for finishing, I found my resin piston frozen in the piston. Couldn't move it even in a vise. Soaked it in recomended lacquer thinner. No help. Used a three pound coffee can, water to cover, little dishwashing soap, and boiled for two hours before I heard the piston pop out of the cylinder. George Krosse Date: Wed, 18 Mar 1998 08:57:33 +0200 From: Rego Burger Subject: COZY: Epoxy Balance In response to folks with jamed pumps, cleaning pumps etc etc. I Never had a problem with my balance scale. I can mix small 50g batches with accuracy. New builders take note. How I made it: The pivot is a miniture ball bearing ( low friction ). The arm / slide has various holes marked to ratios for a range of epoxies. It cost me around $5-00 to make 5 yrs ago and is still doing its job today! Never cleaned it yet. Easy to calibrate with a moving weight. Use the principle in the plans, just add the bearing for those small mixes. Anyone wanting a sketch I'll attach it direct to you not to clutter up bandwidth on the forum. Regards Rego Burger, web site: http://home.intekom.com/glen/rnb.htm (home e-mail) mailto:rnb@intekom.co.za RSA Date: Wed, 19 Mar 1997 03:04:20 +0100 From: Jean-Jacques CLAUS Subject: Re: COZY: Epoxy Balance Rego Burger wrote: > > In response to folks with jamed pumps, cleaning pumps etc etc. > > I Never had a problem with my balance scale. > I can mix small 50g batches with accuracy. > New builders take note. > I made one and it works great. Now i use an electronic balance for the stamp's letter choice ( about 40 usd in France and 0.5g precision ). I keep my first balance scale if the electronic falls down during a layup. Jean-Jacques CLAUS Cosy Classic - FRANCE The Canard Builder's Web Gallery http://www.myagle.org/05/jclaus From: Fritzx2 Date: Mon, 23 Mar 1998 20:28:07 EST Subject: COZY: Max Unmixed EZ Poxy Temperature Does anyone know what the maximum allowable temperature that the unmixed EZ Poxy can be stored without harming it. My temperature controller that kept the epoxy warm went south, way south, and the epoxy got to at least 135 degrees F. I say at least because when I discovered the controller had failed, one of the two heater bulbs had burned out and it is possible that for some time in the preceeding 24 hours that both bulbs where working and the epoxy got even hotter than it was when I found it with only one bulb working. If no information exists for EZ poxy, does anyone remember seeing any max temp. for Safe-T-Poxy listed in an older C.P.? I might be using that new delivery of EZ Poxy sooner than I was planning on. Lesson here is to have a backup temperature sensing circuit or button thermostat that will unlatch the faulty heating circuit in case of a thermal runaway. Longer term, I was planning on adding a backup but I guess Murphy couldn't wait that long:). Thanks, John Fritz fritzx2@aol.com Date: Sun, 22 Mar 1998 20:55:49 -0500 From: "Jeff S. Russell http://www.AeroCad.com" Subject: Re: COZY: Max Unmixed EZ Poxy Temperature Fritzx2 wrote: > Does anyone know what the maximum allowable > temperature that the unmixed EZ Poxy can be stored > without harming it. John, CPD has tested storgage at 150 with no problem. 80 to 100 is best for the heat range when you mix. Any hotter the epoxy could and will exotherm when you mix it :-) -- Jeff Russell/AeroCad Inc. E-mail: jraero@gte.com P.O. Box 7307 Port St. Lucie FL. 34985 Shop# 561-460-8020 Home# 561-343-7366 Composite workshop info: http://www.Sportair.com Date: Tue, 24 Mar 1998 08:03:43 -0500 From: Paul Krasa Subject: Re: COZY: Max Unmixed EZ Poxy Temperature IMO 135deg. will not hurt a thing; my justification is when the hardener is crystallized the process for getting the crystals back into solution is to heat hardener up in a double boiler. I heated my hardener up to 160 deg., now it works great. The expert is Gary Hunter though, and if he is not on this news group, he is on Canard Aviators. Paul Long EZ 214LP Still fighting fuel leaks At 20:28 3/23/98 EST, you wrote: >Does anyone know what the maximum allowable >temperature that the unmixed EZ Poxy can be stored >without harming it. My temperature controller that >kept the epoxy warm went south, way south, and >the epoxy got to at least 135 degrees F. From: Greg and Jill Hilliard Subject: COZY: epoxy mixing Date: Wed, 25 Mar 1998 07:07:14 -0600 Hi all, I'm getting ready to do the first layup on the inside fuselage (ch 5) = this sunday. I am currently dispensing EZ10-84 epoxy from the AR-100 = adjustable ratio pump sold in both Wick's and Spruce. The bucket on the = hardener side is almost full ( < 1/2 gal, maybe 60 oz.), but after that = I am switching over to EZ10 with the 83 hardener. My question is this:=20 1:when keeping the same resin system but changing hardeners can I mix = these two in the same layup? 2:do I need to clean out my pump when switching over? 3:if yes to (2), do I have enough of the 84 hardener right now to make = it through this layup, considering I will also be vac bagging and will = want to wet out peel ply. I suspect I do, but then I don't have as much = experience with how far this stuff goes as some of you might. I've got a friend helping who will lend his scale, so I'm covered if = (1) is yes and (2) & (3) are no, but if (1) & (3) are no, then I will = have to clean out my pump before the weekend and save the EZ10-84 for a = smaller job later. As this would be a pain in mine arse, I would rather = not unless you all decided it was warranted. Thanks in advance, Greg Hilliard Cozy mk4 #456 gjhilliard@idcnet.com From: Marc J. Zeitlin Subject: COZY: epoxy mixing Date: Wed, 25 Mar 98 8:53:09 EST Greg Hilliard asks; >1:when keeping the same resin system but changing hardeners can I mix >these two in the same layup? I'm not an expert in the epoxy area, but I wouldn't mix hardeners, either in a batch or in a layup. >2:do I need to clean out my pump when switching over? I would, for the same reason as #1 - don't mix the hardener. >3:if yes to (2), do I have enough of the 84 hardener right now to make >it through this layup......... Geez, yes. You better not use the whole bucket of epoxy on the inside fuselage, or else you're empty weight will end up at about 1600 lbs. :-). > I've got a friend helping who will lend his scale, so I'm covered if >(1) is yes and (2) & (3) are no, but if (1) & (3) are no, then I will >have to clean out my pump before the weekend and save the EZ10-84 for a >smaller job later. Assume that you can get through this layup (and some others) with what you've got. When you get to the point that the hardener bucket is just about empty after some smaller layups, empty the hardener bucket and clean it thoroughly. That way, you're safe no matter what. -- Marc J. Zeitlin Email: marcz@an.hp.com Date: Wed, 25 Mar 1998 18:15:57 -0600 From: Mike Davis Subject: Re: COZY: epoxy mixing I'm reasonably sure that mixing of the RAE system was okay. On the otherhand I have not heard of anyone advocating mixing any other system. P.S. The first strake is going on my second MkIV. Date: Tue, 24 Mar 1998 10:20:22 -0500 From: "Jeff S. Russell http://www.AeroCad.com" Subject: Re: COZY: epoxy mixing > Greg Hilliard asks; > > >1:when keeping the same resin system but changing hardeners can I mix > >these two in the same layup? We do this all the time. Today we made an AeroCanard top fuselage. The Cowling is part of the top fuselage mold and is laid up in the mold with EZ87 hardener first. Then we finish the rest of the outside skins with EZ84 hardener. We use two different pumps instead of changing the hardener in one pump. I have done this in the past with no problem. I asked CPD and Hexcel about doing this and the OK was given. Even the old Safe-t-poxy can be mixed with the new EZpoxy. I also have tried this and it passed all of the test. -- -- Jeff Russell/AeroCad Inc. E-mail: jraero@gte.net P.O. Box 7307 Port St. Lucie FL. 34985 Shop# 561-460-8020 Home# 561-343-7366 Composite workshop info: http://www.Sportair.com From: Lee Devlin Subject: COZY: Epoxy properties Date: Wed, 22 Apr 98 13:44:49 MDT After dutifully reading the more than 11,000 lines of text in the archives related to epoxy, I will now post this question. Has anyone come up with a matrix that compares all the epoxy properties? I was interested in knowing exactly how to compare the newest epoxies Nat mentioned in the newsletters (MGS L285 and L335?) to others with which I am familiar. Specifically, I'd be interested in the following information: Manufacturer(s) tensile strength viscosity intensity and type of odor wetting characteristics pot life cure time Tg (glass transition temperature with and without PC) post cure (PC) temperature, time common builder problems, if any mix ratio color known hazardous ingredients (e.g. MDA) avg. cost/lb. availability I'm sure there are other properties I missed. Rego posted some very interesting tests he had run which did include some of the properties mentioned above. (It's in the archives). I think that a matrix of this type would be of enough value that it could potentially linked into Marc's web site for all eternity thus making the person(s) who put it together famous. (That's an inducement to get someone other than myself to do some the legwork :-) Thanks, Lee Devlin LongEZ N36MX http://members.aol.com/lee810 From: lschuler@cellular.uscc.com Date: Wed, 22 Apr 98 15:34:03 -0600 Subject: Re: COZY: Epoxy properties Lee Devlin wrote: After dutifully reading the more than 11,000 lines of text in the archives related to epoxy... >snip Uh-Oh; Pandora's box is open again..... Just a side note. probably in the archives, but worth repeating. When and if a list is obtained, caution is advised on the way some manufacturers provide specs. Some may list the properties as used in a glass matrix; others do their testing 'neet' (no glass) for example. There are also variations in post cure schedules and ad nausium. Important to compare apples to apples. I believe there are some standard ASTM methods that would help keep the comparisons on an even footing. Trick is to get the manufacturers to publicize or quote the methods used.... Good luck! An independant tester/lab can do same prep and exact same test on all types with mutiple iterations using exactly the same test hardware. Few manufacturer's will agree on anything, beginning with the price to charge for stuff with exactly the same ingredients. This is one of the very good reasons Rego's info is so interesting. He was an independant tester trying to duplicate all tests for all epoxies in a reasonable manner. Larry Schuler Plans #500 lschuler@cellular.uscc.com Date: Wed, 22 Apr 98 15:28:51 EDT From: "Hill-EQE-EQE, Dana" Subject: COZY: Epoxy use, what brand? To all cozy builders that are just starting or have started recently; I have decided to begin this project with the newly available german epoxy. If you could would you please let me know (and the other builders) which epoxy you decided to begin with (Ch. 4-Bulkheads) and your impressions of it to date? After my initial layups this weekend/next week I will report back on the German resin/hardner. THANKS! _____________________________________________________ Dana Hill dana.hill@state.ma.us Ch 4, Cozy IV From: Lee Devlin Subject: Re: COZY: Epoxy properties Date: Thu, 23 Apr 98 17:46:36 MDT Larry Schuler wrote: > Important to compare apples to apples. I believe there are some > standard ASTM methods that would help keep the comparisons on an even > footing. Trick is to get the manufacturers to publicize or quote the > methods used.... Good luck! This is a very good point. In the archives the post-cured Tg for 2427 was given as 240F. I was elated since I'm building a composite prop so I'm concerned with Tg and wanted to use up my 2427 which has always worked well for me. Later, I read a posting where Jeff Russell had performed an actual test. He found the Tg for 2427 to be 210F. Well, that was still better than specs for EZ10 (195F) and the new MGS L335 (185F). (The new MGS L285 has a Tg of 240F but it also has an odd mix ratio that is so close to 44:100 that I think it would be impossible to modify the pump for it since the holes would overlap to form a slot.) I got a fax from CPD Epoxical and they are making a replacement for 2427 called 9327 and it shows a Tg of 168F using ASTM D-4065. So, yes, I realize that there may be a lot of inconsistency on how these properties are measured but I think that they can be apples-to-apples if we are careful on how we collect the data. Based on the number of responses I got to this subject, it appears I'll be on my own. I can already taste the glory :-). Lee Devlin LongEZ N36MX http://members.aol.com/lee810 From: "L. Wayne Hicks" Subject: COZY: First Draft of User-Friendly Epoxy Summary... Date: Fri, 8 May 1998 10:20:21 -0400 Gang: As a new builder, the question of "which epoxy to use" can be undaunting. Learning the language, coding, and trade names takes time and experience. To get smarter and up to speed, I rolled up my sleeves last night and went digging. After several hours digging through Zeitlen's website, I compiled all the epoxy discussions from previous newsletters and summarized it. It was an educational experience. I figured it might be useful for other people, too. I can't vouch for total accuracy, since after all, I'm just beginning Chapter 4 and it was 1 o'clock in the morning. I have asked Nat and Marc for comments. (Others that can contribute can e-mail me separately, please.) Maybe I can get with bil kleb (why does he use all-lower case letters :-) ?) and turn it into a FAQ. Sounds like most people use EZ10. The German epoxies sound promising. Aeropoxy looks good, too. I'd like to know more about "stink factor". I'm worried about the stink factor lingering long after the plane's built. I can imagine the canopy closed, outgassing for hours under the mid-day sun, open the canopy and whoosh...bowled over by epoxy outgassing. That "boat-hull-smell-on-a-hot-summer's-day" makes many people nauseous, including my wife and several of my friends. From practical experience at SNF: 1. Those planes made from original RAE have a definite epoxy smell, like being in a boat hull on a hot summer's day. 2. Those made from Aeropoxy had no smell. 3. Those made from EZ10 had a trace of smell. EPOXY Summary Here is a list of epoxies that have been and still are approved by RAF (and Nat): Epoxy Kit Price (approx.) ----- ------------------- Aeropoxy 2032/3660(P[M&W) $53/ 1.0 gal RAE 2426/2176 & 2177 69/ 1.25 gal West 105/209 (Gougeon Bros) 79/ 1.20 gal E Z Poxy (formerly Safe-t-Poxy) 83/ 1.25 gal Proset 125/229 (Gougeon Bros) 110/ 1.25 gal Hexcel RAE SYSTEM - (Epolite 2426 resin, 2176 fast hardener, 2176 slow hardener) Original epoxy resin system used by RAF Contains no MDA and is generally non-toxic Hexcel SAFE-T-POXY Developed as an alternative to the RAE system for those who developed allergies Brown-colored, aromatic odor, hardener catalyst contains MDA (carcinogenistic). Thickens in the pot before exotherming Taken off the market at Burt Rutan's urging because it contained MDA. Hexcel SAFE-T-POXY II (Epolite 2410) Is this the same as EZ-Poxy??? (Yes, I think so...) Modified version of SAFE-T-POXY, lower viscosity "Stabilized" MDA reduces chance of exposure Hexcel EPOLITE 2427 Replaces SAFE-T-POXY. Better than RAE system Practically colorless, nice low viscosity, and very nice properties. Must complete layups faster to ensure peel strength. Sensitive to moisture and carbon dioxide contamination than other systems Important to keep the containers tightly sealed, displace air and humidity Later DISAPPROVED!! Aeropoxy (P&W PR2022) Higher viscosity than Safe-T-Poxy Hexcel PR2032 resin and PH3660-2 catalyst Colorless, higher viscosity than RAE epoxies and Safetv-Poxy II. Does have higher glass transition temperature, but wets out slower Mixed reviews from builders Gougeon Proset 125/229 Premium epoxy resin system (most expensive) Quite thin, so vertical layups might be trouble Must be post-cured to obtain full strength New German Epoxies (L335, L285) Orderless, cures almost clear, low-toxicity Low viscosity, but better that Proset on vertical layups Post-curing is probably advisable until more is known about it's characteristics Under evaluation by FAF, Nat (???), but not yet recommended by RAF (???) Not Approved Poly-Epoxy WEST __________________________________________ L. Wayne Hicks SpaceTec, Inc. Program Manager 3221 North Armistead Ave. 757-865-0900 voice Hampton, VA 23666 757-865-8960 fax http://www.spacetec-inc.com __________________________________________ L. Wayne Hicks SpaceTec, Inc. Program Manager 3221 North Armistead Ave. 757-865-0900 voice Hampton, VA 23666 757-865-8960 fax http://www.spacetec-inc.com From: "Nat Puffer" Subject: Re: COZY: First Draft of User-Friendly Epoxy Summary... Date: Fri, 8 May 1998 08:58:17 -0500 Dear Cozy Builders, I am not aware that anyone who has completed a Cozy and is flying it has ever complained about any residual fumes inside the cockpit. I have been flying composite airplanes since 1978, if that is any consolation. I haven't seen any other pilots answering these concerns. It mostly involves chats between builders who have not completed their airplanes yet. Epoxies should have no volatiles left after they have cured. All of the components are used up in the chemical curing process. What makes these concerns even less credible is the fact that you will be flying almost always with ventilation, either cold fresh outside air or heated outside air. Best regards, Nat Puffer Date: Fri, 08 May 1998 12:42:00 -0400 From: bil kleb Subject: Re: COZY: First Draft of User-Friendly Epoxy Summary... Nat Puffer wrote: > > Epoxies should have no volatiles left after they have cured. > All of the components are used up in the chemical curing process. this seems to imply an absolutely perfect (down to the molecule) mixing. there are _always_ uncured resin and hardener components around. > > From: L. Wayne Hicks > [nat had included the _ENTIRE_ previous post] -- bil From: "Nat Puffer" Subject: Re: COZY: Aeropoxy and Fuel cells Date: Fri, 8 May 1998 09:32:21 -0500 Dear John, I am aware that some kit manufacturers us vinyl ester resins, I have not. Vinyl ester resins are related to polyester resins. Polyester resins are not as good as epoxy resins. We are a licensee of RAF, and they have never approved vinyl ester resins, nor do I believe they use it in all of the composite airplanes they design and build. I have no evidence myself, nor do I know of evidence that vinly ester resins are superior to epoxy resins in the construction of composite aircraft. The record on epoxy resins in the construction of composite aircraft should speak for itself. There are many Variezes, including my own, which have been flying for 20 years. Even if vinyl ester resins are equally good, I don't think they have 20 years of experience behind them. We have said many times that we don't approve things which RAF has not approved, nor have we tested. Best regards, Nat From: cdenk@ix.netcom.com Date: Fri, 8 May 1998 19:14:45 -0500 (CDT) Subject: Re: COZY: First Draft of User-Friendly Epoxy Summary... L Wayne Hicks writes You should and normally happens, have a constant supply of fresh air in the cockpit. Any very small outgassing would be quite dilute. Probably outgassing of the paint, exhaust fumes (or humans) would be more concern. Never heard of anyone complaining of any of the above, other than exhaust fumes and oil that got on the exhaust pipes.. Date: Sat, 9 May 1998 14:36:09 -0400 From: Lee810 Subject: [canard-aviators] New German Epoxy [The Canard Aviators's Mailing list] I've been following the discussion on epoxies for quite some time. It appears that one of the numbers that has got a lot of people confused (especially me) is the Tg or glass transition temperature. There are actually two epoxies available at Wicks from MGS (Martin G. Scheuffler in Germany). The one that has the same mix ratio as SafetyPoxy (100:45) is L335 which has a room temperature cure Tg of about 130F (this according to the most recent Cozy Newsletter). This number can be improved to 185F by post curing at 160F for 16 hours. The other epoxy is L285 and that has a much higher Tg of 240F, provided it is cured at 170F for 16 hours. The room temperature Tg of the L285 was not given. This epoxy has a mix ratio of 100:50 by volume. To put this in perspective, the Tg for SafetyPoxy cured at room temperature is between 142-151F according to the Aircraft Spruce catalog. If you post cure at 150F for two hours, you can increase that to 196F. Now, there are lies, damn lies, and spec sheets. I know from my own experience that the accuracy of measurement and methods of testing alone could account for a 10-20F variance of Tg's depending on how the respective companies wanted to report them. Depending on the sample, Tg may actually occur over a range of temperatures. So how would you expect it to be reported? Well, a conservative company might report a number they are sure all samples would meet whereas an optimistic company may state the average or even the maximum properties they ever recorded. I don't think that MGS epoxies will behave any differently than what we've become accustomed to using. The fact that it is actually approved by the German FAA makes me feel that it has been much more thoroughly scrutinized than the epoxies we've been using for experimental aircraft for years. Lee Devlin LongEZ N36MX http://members.aol.com/lee810 ---------------------------------------------------------------------- (c) 1997 Canard Aviators. This information is provided solely and exclusively for the personal use of Canard aircraft builders and Pilots and may not be used, copied, quoted or referenced in any other publication or medium without the express written consent of Canard Aviators support@canard.com. From: "cozymkiv" Subject: COZY: EZ Poxy Hardener Date: Tue, 12 May 1998 20:55:46 -0500 In mid March, I received two 1=BD gallon kits of E-Z poxy from Aircraft Spruce. I just got around to using them yesterday. When I open one of the cans of hardener (EZ 84) I noticed it had a peculiar appearance. Instead of being the usual translucent dark amber color, the hardener looked like someone had poured in a cup of milk. The second can of hardener is the same. I read through the archived information on epoxy and saw the line o= f discussion about crystalization. I live in south Texas and the lowest the temperature has been since I got the hardener was in the low 50's. Both cans had not been opened and were still sealed under the lid. Does it sound like I have the crystalization problem or should I start raising hell with A. Spruce? (Lot # of both cans: 15221). Thanks for your help. William E. Buckley (COZY Mk IV, Chap 19 {sort of}) cozymkiv@intcomm.net Fly NAVY!!! From: Marc J. Zeitlin Subject: COZY: EZ Poxy Hardener Date: Wed, 13 May 98 8:50:59 EDT William E. Buckley wrote; >....... When I open one of the >cans of hardener (EZ 84) I noticed it had a peculiar appearance. Instead >of being the usual translucent dark amber color, the hardener looked like >someone had poured in a cup of milk............ Does it >sound like I have the crystalization problem or should I start raising >hell with A. Spruce? (Lot # of both cans: 15221). Sounds like crystallization. The stuff could have gotten cold at ACS, or before they got it. You can test this by heating the hardener cans in a pot of very hot water until the hardener gets up to 150 - 180 F for a while. If the white stuff goes away, it was crystallization, and the hardener will be perfectly usable. Make a test batch of epoxy and do a scratch test to be sure. If the white stuff does not disappear, or if the epoxy does not pass the scratch test, hit up ACS for replacements. My $0.02. -- Marc J. Zeitlin Email: marcz@an.hp.com From: lschuler@cellular.uscc.com Date: Wed, 13 May 98 11:19:07 -0600 Subject: Re: COZY: EZ Poxy Hardener Marc Zeitlin wrote: >Sounds like crystallization. The stuff could have gotten cold at ACS, or >before they got it. You can test this by heating the hardener cans in a >pot of very hot water until the hardener gets up to 150 - 180 F for a >while. If the white stuff goes away, it was crystallization, and the >hardener will be perfectly usable. Make a test batch of epoxy and do a >scratch test to be sure. >If the white stuff does not disappear, or if the epoxy does not pass the >scratch test, hit up ACS for replacements. Be sure to stir it up after heating (per manufacturer info). Larry Schuler lschuler@cellular.uscc.com Subject: Re: COZY: yet another epoxy system Date: Tue, 16 Jun 1998 09:17:53 -0400 (EDT) From: "Randy Smith" Bil Kleb wrote: (I'll use the shift key even if bil won't :-)) > last october randy s wrote about fibre glast's new system 2000 epoxy. > he mentioned that he spoke with one of their reps and had a quart of > resin sent to nat for testing. Well, actually I gave Nat's name and contact information to the rep with encouragement to contact Nat so that the approval process could begin. I told the rep that until it becomes an approved resin system by Nat that most builders, including myself would look upon system 2000 with a wary eye. I have no clue if the instruction was ever followed. I have NO experience with any epoxy system (yet :-)) as my sig line states we sold our house (and my shop that was ready to begin building) and the buyer wanted my jig table (put it in the contract). So I have a new house but get to build a bigger shop (and better table) all over again. That being said though, I agree that the numbers on the system 2000 do compare well and I too would like to see if real world meets expectations. > as he mentions, they have a chart comparing their system to saf-t-poxy > (2410/2183+2184), epolite (2427), ez poxy (ez10/ez83+ez84), > rae (2426/2177), and pro set (125r/229h) for a 10 ply hand layup of > 7781 fabric. their numbers (including the price) appear better across > the board although the viscosity appears to be a little higher than > most. they site astm testing methods. I have the chart as an excell spreadsheet and can email privately to anyone interested. -Randy --* --- -* **-* *-** -*-- -* Table SOLD! Cozy MkIV on hold | _ | NCR General Purpose Computing Randy.Smith@ColumbiaSC.NCR.COM |---( )---| Global Support Center Voice 803-939-7648, V+ 633-7648 ___o/o\o___ West Columbia, SC 29170 "I am the way, the truth, and the life..." -JC From: SBLANKDDS@aol.com Date: Thu, 18 Jun 1998 21:56:05 EDT Subject: COZY: Cozy: 5 minute epoxy tip I used the underside of my epoxy cups to mix the 5 minute stuff. No waste of cups. Also, I keep on jar for left over resin (first pump each day), flox, micro....and toss in all the sharps waste (knife blades, bent nails...etc). This makes for safe garbage. jar stays under my epoxy pump for drips. Date: Fri, 19 Jun 1998 10:57:32 -0800 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: Re: COZY: Ch 4 - Connecting foam boards for bulkheads >hrogers writes <5 minute epoxy at fuel tanks> > >I'm not sure I agree, I don't know the effect of fuel on the 5 minute. In >this area you need all the >help you can get to prevent leaks. The fuel can and has for some, found >the hardest places to repair >or even find to leak. Remember the photo in the last CSA newsletter of a >LONGEZ hanging nose down >from the hanger roof to repair a leak. Oh, I agree completely. The joints I was referring to were mostly the ribs to the inside skin bonds, where there is no path to the outside world, as in a seam. If I did use it near a seam, the 5-minute "tack" would be on the outside only, and would then be completely buried inside regular epoxy-micro, and glassed over, to boot. I wasn't suggesting that you should rely on 5-minute for either sealing or structural strength, but to merely use it for the purpose of holding things in position while they cure. I never worry about its strength when it is bonding anything to foam, because just about anything is stronger than the foam itself. --Howard Rogers, 650-926-4052 hrogers@slac.stanford.edu From: Epplin John A Subject: COZY: Epoxy, L285 slow & fast hardener Date: Wed, 24 Jun 1998 11:42:55 -0500 I started using the L285 resin a couple of weeks ago. This seems to be an excellent product, very low viscosity, wets out easily and ends up with what appears to be a very good laminate in less than 24 hours. It is much harder than Aeropoxy next morning, can be sanded no problem. Nat had good words about it in the latest newsletter. One thing he mentioned makes me ask the following dumb question. Can the hardeners be mixed to produce a intermediate speed hardener? I have no idea of the magic that goes on in the hardening process. My experience with the fast hardener in the present time of year is it is a little fast, don't mix very much at a time and keep the process going or you will have a problem. I cannot get anyway near the 40 to 45 min pot life indicated on the 285 can. I realize this is for 20 deg C or 68 F and I was about 80 F at the time or 12 deg above spec. This should double the cure rate if I understand this stuff correctly. I was getting 10 min pot life with less than 50 gram mixes without any concern but much more than that I would notice the cup heating. It would be nice to extend that a bit but not all the way out to the 4 hr. indicated for the 287 hardener. Any epoxy experts out there that know if this is a suitable option? John Epplin Mk4 #467 From: "Nat Puffer" Subject: Re: COZY: Epoxy, L285 slow & fast hardener Date: Wed, 24 Jun 1998 10:02:49 -0500 Dear John, I thought I covered this in my newsletter. One of the advantages of the German epoxies is that they have two different hardners, a slow and a fast, which can be mixed together in any proportion to achieve any pot life (and cure time) you want. Regards, Nat Date: Thu, 25 Jun 98 11:25:49 1100 From: Chris Byrne Subject: COZY: German Epoxies L285/L335 Dear Builders=20 During the process of evaluating the feasibility of importing the German = epoxies into Australia for my own use I have gained some very good inform= ation from the Scheufler factory in Germany. =20 The following is some info on the pot life of the German L335 epoxy, whic= h I have taken directly from the e-mail I received. I guess the mix of the L285 and its hardeners would be similar. Hardener 335 and 340 can be mixed together, in order to get a suitable po= t life. Potlife of 100g mix L335/hardener335 at 25=B0C is aprox 15min, 10= 0g mix L335/hardener340 at 25=B0C is more than 5h. Geltime in the laminat= e is even longer. To give you a rough idea of potlifes among different ha= rdener mixtures Hardener335: Hardener340 Processing time 100 0 10-15min 50 50 60-90min 20 80 approx4h 0 100 approx6h Info on the L285 versus the L335 The L285 system got its aircraft approval in 1985 and is one of our oldes= t systems. This system is used by nearly the entire glider industry world= wide. Maximum possible Tg=B4s are L285 Hardener 285: 90-95=B0C L285 Hardener 286 105-110=B0C L285 Hardener 287 110-115=B0C To reach that value, a heat treatment of 100=B0C is necessary. Most glider companies do their postcuring at only 50-55=B0C for 15hours. = Possible Tg=B4s after that cure cycle are in the range of 70-80=B0C. The= static and dynamic strength that the material reaches after this heat tr= eatment has proven to be o.k. for gliders, however, there are some disadv= antages: -The material is not completely cross linked, in my opinion this is the r= eason that the material shows a (very small) amount of shrinkage after so= me time. If you take a look at the brand new gliders, you can see the spa= r cap and the fabric structure in the wing after approx 1/2 year. If the = material was cured completely, that shrinkage should be less. It is not a= problem concerning any aerodynamics or stress levels, but it makes an op= tic problem for some companies. -The price for the L285 system is relatively high Mainly the high price and the understanding that they do not need that re= serve in Tg from 80 to 115=B0C was the reason to develop a new system wit= h a lower Tg at a more favourable price: the L335 system which got its ap= proval last summer. The maximum Tg for that system is in the range around= 80=B0C and is nearly reached after a heat treatment of 60=B0C, completel= y cured after 80=B0C. Glider companies in germany are starting now to use= that system in their serial planes, it is a great success in the US wher= e it is distributed by Wicks and Spruce.=20 Chris Byrne Sydney Date: Thu, 16 Jul 1998 10:21:57 -0700 From: marcna Subject: COZY: Heat and WestSystems I've been working on the finish and with the recent heat I have found that the West Systems epoxy and micro mix kicks off before it can be applied. The temp in the hangar has gotten a high a 105 this week. Maybe you folks in Texas have a solution. I thought of using a little less hardener in the mix, or putting the epoxy in the fridge. Marc Parmelee -- ____ _____ __ / ___|___ _____ _ |_ _\ \ / / | | / _ \_ / | | | | | \ \ / / | |__| (_) / /| |_| | | | \ V / \____\___/___|\__, | |___| \_/ |___/ From: Epplin John A Subject: RE: COZY: Heat and WestSystems Date: Thu, 16 Jul 1998 12:55:23 -0500 > From: marcna [SMTP:marcna@concentric.net] > > I've been working on the finish and with the recent heat I have found > that the West Systems epoxy and micro mix kicks off before it can be > applied. The temp in the hangar has gotten a high a 105 this week. > Maybe you folks in Texas have a solution. > I thought of using a little less hardener in the mix, or putting the > epoxy in the fridge. [Epplin John A] I assume you are using 206 slow hardener. There may be another slower hardener available, it strikes me there are three in the Geougen Bros. (sp?) catalog. Anyone have a catalog handy? If you are using the slowest available, then about all you can do is mix small batches and maybe cool it a bit as you already suggested. John epplin... Mk4 #467 From: "Brown, Michael" Subject: RE: COZY: Heat and WestSystems Date: Thu, 16 Jul 1998 10:56:00 -0700 Marc: You can use the slow hardener (I think it is PN 206, instead of 205), but I found that just by streamlining your process you can get the stuff mixed and applied before it kicks. I used the fast stuff, kept in my epoxy box at about 100F during the summer and only had a couple batches go thermal on me. While the OAT in So. Cal is more suitable for humans than in other parts of the country, I think you can make the 205 work, and it will really speed up the process - you can sand it in a couple hours, while the 206 takes a lot longer to set up. Recommendations: Use large mixing cups (1 qt. or larger) Put a mixing paddle on your electric drill Squirt the epoxy in the cup and do a quick mix by hand for 30-60 seconds max Throw in the micro Put a lid on the cup Mix with the drill for a minute or until smooth Run to airplane and spread quickly Sand Repeat Sand Repeat............. Have fun, (beer helps) Mike Brown N97PZ (200hr. in 10 months!) Redondo Beach, CA -------- Marc Parmelee wrote: >I've been working on the finish and with the recent heat I have found that the West Systems epoxy and micro mix kicks off before it can be applied. Date: Thu, 16 Jul 1998 14:23:35 -0400 From: Paul Krasa Subject: Re: COZY: Heat and WestSystems snip Your only recourse is to use West Systems slow hardener and mix up small batches. The fast hardener will exo if you mix up more than two squirts at a time when it is warm outside. If it is hot you may not be able to use the fast hardener at all. Paul Krasa Long EZ 214LP From: "Hunter GA (Gary) at MSXSCC" Subject: RE: COZY: Heat and WestSystems Date: Thu, 16 Jul 1998 13:52:09 -0500 Mark Parmelee wrote: > I've been working on the finish and with the recent heat I have found > that the West Systems epoxy and micro mix kicks off before it can be > applied. The temp in the hangar has gotten a high a 105 this week. > Maybe you folks in Texas have a solution. > I thought of using a little less hardener in the mix, or putting the > epoxy in the fridge. > The curing reaction doubles in rate every 10C. So, yes - the stuff does kick off many times faster on a hot day. Under no circumstances are you to cut back on the level of hardener.... this is not polyester resin. Keeping the resin cool is good idea. I wouldn't necessarily put it in the fridge. Just keep it inside the house that is hopefully air-conditioned. Bring it into the shop when you are ready to mix and go. Many of you may have noticed how adding the micro to the resin mix seems to make the mix get hotter than it normally does. Well, you are not imagining things. It does get hotter. Much of the working time that is available under these temperature conditions is being consumed while mixing in the micro-balloons, glass bubbles or whatever you prefer to call them. The thing to do is pre-weigh the resin and hardener into their separate containers. Add the micro to the resin container and the curing agent containers separately. Then combine the two together and mix thoroughly right as you need it. You may need to add more bubbles as you go. But, at least the bulk of the bubbles were stirred in when time wasn't critical. Gary Hunter EAA Technical Counselor Vari-Eze - N235GH gahunter@shellus.com Date: Thu, 16 Jul 1998 12:45:50 -0800 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: Re: COZY: Heat and WestSystems Good suggestions from all. I particualrly like the one about using the drill to mix. I've got to try that one. One additional comment: Whatever you do, DON'T reduce the amount of hardener! This works fine with polyester, but not with epoxy. The ratio must be maintained, or you will have leftover, uncured resin mixed in with the whole mess. This may not be immediately obvious, which is even worse, as you may discover it as your beautiful paint job bubbles up and flakes off! --Howard Rogers, 650-926-4052 hrogers@slac.stanford.edu Date: Thu, 16 Jul 1998 13:02:53 -0800 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: RE: COZY: Heat and WestSystems >Many of you may have noticed how adding the micro to the resin mix seems to >make the mix get hotter than it normally does. Well, you are not imagining >things. It does get hotter. Much of the working time that is available >under these temperature conditions is being consumed while mixing in the >micro-balloons, glass bubbles or whatever you prefer to call them. This is very true. There is another reason that things speed up with micro. It is a very good insulator, which makes the entire mixture conduct heat poorly. After all, micro is mostly empty space. You have now mulitplied the volume by several and the surface area by not nearly as much. The heat cannot travel through the mixture to the surface nearly as fast, to escape, and there is proportionally much less surface to escape to. Keep it cool. Mix it fast. Get it spread out THIN, as quickly as possible. Not much else you can do. -Howard Rogers From: Fritzx2@aol.com Date: Thu, 16 Jul 1998 16:42:47 EDT Subject: Re: COZY: Heat and WestSystems Mark Parmelee wrote: > I've been working on the finish and with the recent heat I have found > that the West Systems epoxy and micro mix kicks off before it can be > applied. The temp in the hangar has gotten a high a 105 this week. > Maybe you folks in Texas have a solution. > I thought of using a little less hardener in the mix, or putting the > epoxy in the fridge To which Gary Hunter responded: > The thing to do is pre-weigh the resin and hardener into their separate > containers. Add the micro to the resin container and the curing agent > containers separately. Then combine the two together and mix thoroughly > right as you need it. You may need to add more bubbles as you go. But, at > least the bulk of the bubbles were stirred in when time wasn't critical. I remember reading once that Rutan said not to mix microballoons with hardener before mixing the hardener with the resin since the micro absorbed the hardener which in turn affected the mix ratio. I'm not sure if that caution still applies to the micro that is used now or not. I think the micro material has changed since Burt's recommendation. Any of you with the Canard Pusher newsletters know for sure? I believe I read the original caution in a CP. John Fritz From: David de Sosa Date: Thursday, July 16, 1998 6:52 PM Subject: Re: COZY: Heat and WestSystems I second this opinion. If there are any surface attraction differences between resin and hardener with respect to attachment to microspheres, this could definitely throw off the original mixing ratio between the hardener and resin. Also, I would think that the region of hardener or resin in close proximity to the microsphere surfaces would not tend to mix as well when the other mixture is stirred in because the microspheres would block out some of the agitation action between molecules of resin and hardener. >From a non-chemist David de Sosa Cozy MKIV #80 From: cdenk@ix.netcom.com Date: Thursday, July 16, 1998 7:43 PM Subject: Re: COZY: Heat and WestSystems >Al Wick writes >When do you clean the mixer, or do you have an endless supply of mixer paddles? From: cdenk@ix.netcom.com Date: Thursday, July 16, 1998 7:48 PM Subject: Re: COZY: Heat and WestSystems >It was wrote >I would not recommend. The micro is somewhat porous (micro size). This is similar to sand and >portland cement. Sand is porous also and moisture content can be in the 10% by weight range and the >sand still appear dry. People have thought they could add portland cement to what they think is dry >sand in a mixer(truck type) and add the water later when they neededthe concrete. The result is >weak concrete since the bonds originally made get broken with more mixing and are unavailable for >bond at the end. > >In the case of epoxy, resin gets absorbed by the micro or other filler and the hardner is unable to >access those molecules to create the necessary chemical bonds. The idea of exact proportions is 3 >fold: 1: to create the most chemical bonds possible (actually there is some tolerance with a >corresponding reduction in strength that is factored into the instructions), ideally all resin bonds >find a mate with all the hardner bonds. 2: Maximize material efficiency. 3: Uncured material will >not be as stable as cured creating long term finish problems and shrinkage. > From ???@??? Fri Jul 17 21:26:03 1998 Received: from twc2.betaweb.com ([206.43.209.18]) by strato-fe0.ultra.net (8.8.8/ult.n14767) with ESMTP id KAA19510 for ; Fri, 17 Jul 1998 10:52:56 -0400 (EDT) Received: (from majordomo@localhost) by twc2.betaweb.com (8.8.5/8.8.5) id KAA04798 for cozy_builders-list; Fri, 17 Jul 1998 10:45:57 -0400 X-Authentication-Warning: twc2.betaweb.com: majordomo set sender to owner-cozy_builders@betaweb.com using -f Received: from gate2.shellus.com (firewall-user@gate2.shellus.com [204.71.91.3]) by twc2.betaweb.com (8.8.5/8.8.5) with SMTP id KAA04791 for ; Fri, 17 Jul 1998 10:45:52 -0400 Received: by gate2.shellus.com; id JAA10146; Fri, 17 Jul 1998 09:41:35 -0500 Received: from unknown(134.163.2.2) by gate2.shellus.com via smap (3.2) id xma008452; Fri, 17 Jul 98 09:39:31 -0500 Received: from icsccxh1 by icsrv01 (AIX 4.1/UCB 5.64/FEJ.AIX.2.1) id AA100530; Fri, 17 Jul 1998 09:39:31 -0500 Received: by icsccxh1.shell.com with Internet Mail Service (5.5.1960.3) id ; Fri, 17 Jul 1998 09:39:37 -0500 Message-Id: From: "Hunter GA (Gary) at MSXSCC" To: "'Cozy Mailing List'" Subject: RE: COZY: Heat and WestSystems Date: Fri, 17 Jul 1998 09:39:32 -0500 X-Mailer: Internet Mail Service (5.5.1960.3) Sender: owner-cozy_builders@betaweb.com Precedence: bulk Reply-To: "Hunter GA (Gary) at MSXSCC" X-UIDL: acd0b0a498ecf9da2086b80cd4e125d0 > John Fritz wrote: > > I remember reading once that Rutan said not to mix microballoons with > hardener before mixing the hardener with the resin since the micro > absorbed the hardener which in turn affected the mix ratio. ...... > David de Sosa wrote: If there are any surface attraction differences between resin and hardener with respect to attachment to microspheres, this could definitely throw off the original mixing ratio between the hardener and resin. ......... cdenk@ix.netcom.com wrote: In the case of epoxy, resin gets absorbed by the micro or other filler and the hardener is unable to access those molecules to create the necessary chemical bonds..... OK, I somewhat expected my suggestion to generate these kind a responses. And that is good. I too remember when the GREAT Rutan spoke and said DON'T... blah blah blah. Come on guys, what he said not to do had already been done since the beginning of epoxy resins. Your arguments are weak. Think about the myriad of two component epoxy adhesives that have been used to bond Boeings and MacD's together for years. These are nothing more than epoxy resins and curing agents with fillers of all types added to them before you mix them together. Clay, wallastonite, gypsum, diatomaceous earth, talc, calcium carbonate, silica flour, aluminum powder, carbon powder, iron oxide, strontium chromate, dust, titanium dioxide - you name it. I will argue, that if any fillers have porosity, etc. significant enough to interfere with the mix ratios and mixing, I just named them. Certainly a hollow microsphere is not intentionally made to be porous. Quite the contrary in fact. Great care is taken in their manufacture to minimize broken sphere content. Normal handling, and mixing will not break them. Isostatic crush strength of the weakest glass spheres (the grade we use) is 250-300 psi. Hand mixing will never break a sphere. BUT, power mixers exhibiting high shear can. And if so, the remnants of the broken sphere are highly fragmented and behave has if they were nothing more than fractured (non-porous) sand particles. The marine industry has been using epoxy fairing putties with microspheres premixed into the resin and curing agent for years. Today, we homebuilders have available to us a product called "Superfil" which is essentially the same kind of material - premixed micro in Resin and Hardener. These putties or fairing compounds use a slightly heavier grade of microspheres with higher crush strengths BECAUSE they use mechanical mixing equipment to mass produce these putties. We don't need the heavier spheres for what we are doing. I can't rationalize why Rutan says some of the things he does. In this case, all I can figure is that maybe he was fearful that builders (with the creative minds we tend to have) would eventually begin making up big batches of Part A and Part B with microspheres to be used as needed over the duration of the project. There are many potential problems that can manifest from this idea - if it isn't done properly. This is not what I was suggesting either. I am in the epoxy business and deal with this too fast / too slow scenario everyday with thousands of Shell's customers around the world. Everytime the seasons change, it starts all over again. What it all boils down to is - you have to control the temperature when you are working with epoxies or ANY thermoset resin. PERIOD Gary Hunter EAA Technical Counselor Vari-Eze - N235GH gahunter@shellus.com Date: Fri, 17 Jul 1998 09:26:49 -0700 From: marcna Subject: COZY: Heat and WestSystems -- I would like to thank all of you for the advice on mixing the filler. I have decided to Portion out Resin and Hardener, place them in cups in the Fridge for a little while and mix the two together and then add my Plastic microspheres. I don't know who the thread got started about mixing micro in hardener first, but that is not what is was doing. When I first started with the filling process I was having problems with the filler laying down when spread on. Larry at Feather Lite told me to add a little CAB-O-SIL to the mix. It worked great. With two pumps of West System I add five 3 oz cups of Plastic microspheres and one 3 oz cup of CAB-O-SIL . For all of you that are going to OSH check out Roy Bailets forum on Contouring and Finishing, its well worth your time. Marc Parmelee / __\___ _____ _ /\/\ __ _ _ __| | __ \_ \/\ /\ / / / _ \_ / | | | / \ / _` | '__| |/ / / /\/\ \ / / / /__| (_) / /| |_| | / /\/\ \ (_| | | | < /\/ /_ \ V / \____/\___/___|\__, | \/ \/\__,_|_| |_|\_\ \____/ \_/ |___/ _ _ ____ ____ ___ _____ | || ||___ \| ___| / __\/ _ / | || |_ __) |___ \ / / \// / |__ _/ __/ ___) / /___ / //\ |_||_____|____/\____/ /____/ From: "Brown, Michael" Subject: Re: COZY: Heat and WestSystems Date: Fri, 17 Jul 1998 09:18:00 -0700 When the micro was fully mixed, I just pulled the paddle up above the micro and ran the drill at high speed for a few seconds - it spun most of the loose micro off the paddle very efficiently. Then, while I was spreading the stuff on the airplane, I left the paddle in a container of solvent to keep the epoxy from hardening on the paddle. Another reason to use large mixing cups and not over-fill them. Mike Brown ---------- Al Wick writes When do you clean the mixer, or do you have an endless supply of mixer paddles? Date: Tue, 21 Jul 1998 07:53:00 +0200 From: Rego Burger Subject: COZY: Heat and WestSystems -pot-life-temp control Hi folks, The other guys are correct about not altering the hardener ratio's...an incorrect ratio will damage the integrity of the mixture. This applies to ALL epoxies... there are many factors that help with temp control, on hot days, I'll mention some that have worked for me on those 30+ deg C days. 1.) Mix in a flat wider container e.g. an ice-cream tub instead of a narrow cup type container, the larger the surface area and the shallower the amount of resin will make it last a few min longer.(pot life) 2.) If you can't afford an air-con ( like a factory) for the workshop and you're not in a drought, apply a sprinkler to spray on the roof of the workshop, the evaporation cools the place down nicely, lead the run-off to your garden. If you have a big roof area this little exercise can drop the room temp between 2-5 deg C. 3.) Place your (plastic not tin) can holding the resin in a larger dish / tub half filled with water. Again the evaporation cools, but the water is normally 2-5 deg C cooler than the air if in shade. "All the above demonstrates the measures we take to build aeroplanes." :-) Rego Burger, web site: http://home.intekom.com/glen/rnb.htm (home e-mail) mailto:rnb@intekom.co.za RSA From: "Neal Newman" Subject: Re: COZY: Simple Homebuilt Post-Cure Oven? Date: Thu, 20 Aug 1998 17:57:23 -0400 I,m very curious about this topic of the MGS epoxys.. I see lots of people asking about the L285... maybe I missed something here... I,m using the L335 epoxy.. am I the only one using it??? ---------- > From: Joseph H. Hart IV > To: cozy_builders@canard.com; canard-aviators@canard.com > Subject: COZY: Simple Homebuilt Post-Cure Oven? > Date: Wednesday, August 19, 1998 11:41 PM > > I am considering using the German L285 epoxy and am interested in > post-curing. No, I don't want to paint my Cozy black, but maybe > silver. Has anyone built any sort of of post-curing apparatus? What > would it take in terms of insulation, thermastatic device, energy > requirements to make an oven of sufficient size to maintain 170 degrees > for sixteen hour stretches? > > Thanks in advance for any information. > > Jody Hart > jodyhart@communique.net > From: John Ellor Subject: COZY: L285 vs L335 epoxy; pros, cons and whose using what? Date: Fri, 21 Aug 1998 11:43:34 -0400 Neil Newman wrote : " I,m very curious about this topic of the MGS epoxys.. I see lots of people asking about the L285... maybe I missed something here... I,m using the L335 epoxy.. am I the only one using it??? " I'm curious on this one too. I'm currently using up my EasyPoxy supply but thinking seriously of switching to MGS. Seems from what everyone says MGS has more problems with atmospheric exposure, but no MDA and no other problems have surfaced so far. As regards L285 vs L335: 1. I notice in my nice new Wicks Catalog that L335 has a mix ratio of 100:45 by volume, which is very conveniently the same as the EasyPoxy and the same as my Michael Eng. Sticky Stuff Dispenser. L285 on the other hand is quoted in Wicks as being 100:50 by vol. so my dispenser ratio would be off ( - yours too Neil). Is everyone using the 285 also using a variable ratio dispenser, or a ratio balance ? 2. In the same source (ya gotta acknowledge) "The 285 system has higher physicals than the 335 and will achieve a higher Tg after post curing..." What exactly that all means in terms of significant impact is TBD. I'm most curious how they both stack up for strength vs the RAE and Safety/Easy Poxy that Burt and many others have in all those Vari/Long Ezes buzzing happily around the sky these past decades. As regards post cure, again, how many of those builders of completed birds actually gave a hoot about it, especially the early ones. It may have been briefly mentioned but was not made a fuss of in my 80's vintage Mk III plans (best I recollect, don't have with me to quote). Best Regards to all, John Ellor Cozy III #283 (trying not to screw up that speedbrake too much.) From: John Ellor Subject: Re: COZY: L285 vs L335 epoxy; etc ....oops! Date: Fri, 21 Aug 1998 15:32:36 -0400 Hi all, I am reminded most courteously by Nat that he discussed these epoxies in Newsletter #61, and also the subject of post cure. (The text of Nats newsletter is also on Mark Zeitlin's web page.) I will remember to re-read the newsletters.... I will remember to re-read the newsletters.... I will remember to re-read the newsletters.... Thanks Nat. John Ellor Cozy III #283 From: "Nat Puffer" Subject: Re: COZY: L285 vs L335 epoxy; pros, cons and whose using what? Date: Mon, 24 Aug 1998 08:17:18 -0500 Cozy Builders, The published ratios for MGS L335 are: 100:38 by weight 100:45 by volume The published ratios for MGS L285 are: 100:40 by weight 100:50 by volume Regards, Nat ---------- > From: Epplin John A > To: Cozy Builders > Subject: RE: COZY: L285 vs L335 epoxy; pros, cons and whose using what? > Date: Monday, August 24, 1998 9:02 AM > > > > > -----Original Message----- > > From: John Ellor [SMTP:jellor@crusher.jcals.csc.com] > > Sent: Friday, August 21, 1998 10:44 AM > > To: Cozy Builders > > Subject: COZY: L285 vs L335 epoxy; pros, cons and whose using what? > > > [Epplin John A] > > As regards L285 vs L335: > > 1. I notice in my nice new Wicks Catalog that L335 has a mix ratio of > > 100:45 by volume, which is very conveniently the same as the EasyPoxy and > > the same as my Michael Eng. Sticky Stuff Dispenser. L285 on the other > > hand is quoted in Wicks as being 100:50 by vol. so my dispenser ratio > > would be off ( - yours too Neil). Is everyone using the 285 also using a > > variable ratio dispenser, or a ratio balance ? > > > > > [Epplin John A] > The 100:50 scares me. The L335 I have says 100:40 on the can! This > is by weight but I am not sure that the by volume may not be the same. I > have mixed over a gallon at the 100:40 by weight, it always passes the > scratch test and seems normal acting. It has been hot around here since I > started to use it, the pot life is a bit shorter than the published times. > About half which probably would be in order as the temp has been mid 80's > most of the time. Anybody know for sure what the ratio should be? > > Scared, > > John epplin Mk4 #467 Date: Mon, 24 Aug 1998 10:06:41 -0500 From: Darren DeLoach Subject: COZY: A long, nasty day.... I spent Saturday glassing the outside bottom of the fuselage, 8 long, hot hours from start to finish, working largely alone (my wife assisted only in stretching the glass in place, not really a one person job). I started at 6 am, and it was already 82 degrees in the garage. By 9 am it was at 92 degrees, and work time plummeted per cup of resin. It eventually peaked at 95 degrees, and the EZPoxy _exothermed_ for the first time ever on me, two cups in a row before I figured out why. Normally I pump about 6-7 strokes of the pump into one of the 8 oz cups when working, never exothermed before. This time only 4 strokes, and it exothermed at the high ambient temperature. I finally started taking the cup inside the house to stir, to cool it down before using it (house smelled real nice, of course...) I was dizzy from the heat by the end of the morning. Needless to say, I spent Sunday buying a window air conditioner unit for the garage, hopefully I'll be better able to maintain the temperature in the 75-80 degree range! I got a Hobbyair respirator at SnF earlier this year, so I should be able to keep the garage door open only small bit to retain the cool, but still have good clean outside air via the respirator. Jeez! -- Darren DeLoach Sales & Software http://www.deloach.com From: Cozy7971@aol.com Date: Mon, 24 Aug 1998 22:36:15 EDT Subject: Re: COZY: A long, nasty day.... In a message dated 98-08-24 11:09:17 EDT, ddeloach@texoma.net writes: << Needless to say, I spent Sunday buying a window air conditioner unit for the garage, hopefully I'll be better able to maintain the temperature in the 75-80 degree range! I got a Hobbyair respirator at SnF earlier this year, so I should be able to keep the garage door open only small bit to retain the cool, but still have good clean outside air via the respirator. >> Darren brings up some old memories. I glassed my fuselage bottom with the help of my wife. We worked in the basement so it was comfortably cool. About halfway through I had to refill the epoxy pump. Just as I started to put the cover on the blue colored hardener my wife came up for a refill. My hand slipped and pushed the cover down into the container creating a tidal wave of hardener that covered her from head to toe. Three or four years later I still try not to discuss it in her presence. I'm currently finishing (heating and insulating) the garage so I can move the plane out of the basement for final assembly. I've been debating putting an old room air conditioner in. Darren's experience decided me I'll cut the hole in the wall this weekend. I also bought the Hobbyaire. It works great and is quite comfortable. Dick Finn Cozy Mark IV #46 From: cdenk@ix.netcom.com Date: Tue, 25 Aug 1998 07:24:19 -0500 (CDT) Subject: Re: COZY: A long, nasty day.... All the bad experiences, time for a good one: At the monthly EAA chapter meeting, I mentioned I was going to be glassing the outside of the fuselage on Saturday, anyone wanted to stop by, could watch, help, or whatever. I had previously cut all fiberglass several inches big, marked key locations and edges with a felt tip pen and organized everything. Had 2 experienced fiberglass people, and 6 others appear at 8:30AM. Was able to have people mixing epoxy, slurry, wetting out, squeeging was left to the experienced. I don't think I could have left mixing to others with a scale, the ratio pump is a must. When placing the fiberglass, 16 hands enabled stretching and setting it exactly where wanted with very minimum additional straightening of fibers. By 11:30AM one half was complete, and my wife,Joan, had lunch prepared which we ate on the back porch. After a half hour lunch break, back to work, and by 2:30PM everything was complete. A total of 6 hours!! 2 Lessons: Don't be too proud to ask for help, and preparation, preparation,preparation. Date: Tue, 25 Aug 1998 07:09:20 -0700 From: Tim Hustad Subject: Re: COZY: A long, nasty day.... bil kleb wrote: > > Darren DeLoach wrote: > > > > [...] it was already 82 degrees in the garage. By 9 am it was at 92 > > degrees, and work time plummeted per cup of resin. It eventually peaked > > at 95 degrees, and the EZPoxy _exothermed_ [...] > > this sounds strange to me. i have mixed plenty of "12 pump" batches > (nearly full 8 oz cup) in 90-100 degree virginia heat. i have never > experienced an exotherm unless i left the epoxy in the cup too long. > the epoxy stays in the cup only long enough to mix it (~2 minutes). > in fact, even in the winter, i keep our garage around 85 deg F to keep > the viscosity low which greatly speeds wetting out the glass fibers. > > the key to avoiding exoterm is to keep the surface area-to-volume ratio > as high as possible, i.e., spread it out--don't keep it in a cup too long. > > -- > bil The only time I had EZ poxy exotherm was in a 85 degree garage and 10 pumps. My wife and I were doing the inside bottom at 0430 Easter morning and my son was helping. I asked him to use 4-5 pumps. He decided to help and use 10 pumps. When he handed it to me I could tell it was getting warm. So I made a bigger mistake and tried to spread it real quick thinking that would make it okay. It wasted alot of time and I have more epoxy in that area than I need. Tim Date: Tue, 25 Aug 1998 09:54:46 -0500 From: Darren DeLoach Subject: Re: COZY: A long, nasty day.... >this sounds strange to me. i have mixed plenty of "12 pump" batches >(nearly full 8 oz cup) in 90-100 degree virginia heat. i have never >experienced an exotherm unless i left the epoxy in the cup too long. It was near the end, when I was doing the small 3-layer reinforcement layups in the LG area, so the epoxy was sitting in the cup for several minutes after stirring, as I was using a small amount at a time. Hadn't really been a problem before now, I had assumed EZPoxy just didn't exotherm in my batch size because I'd never seen it in the past year of work! -- Darren DeLoach Sales & Software http://www.deloach.com Date: Wed, 02 Sep 1998 20:45:31 -0400 From: Ian Douglas Subject: Re: Fwd: COZY: Intrument panel stiffeners ribs and other Qs >One last question. A couple of weeks ago I got a slight burning sensation in >my forehead and checks after doing a lay-up. No rash and no redness but it was >noticeable....... I use gloves and ply9 cream. I haven't used a >respirator although I'm also correcting that. Is a slight skin reaction from >over-exposure to the epoxy normal or is this a sign that I should stop >thinking I'll be able to build this airplane because of epoxy sensitivity?. Switch to Aeropoxy, it works great and has next to no smell. I have a large shop but have to keep the doors closed (moskitos and flys). After 12 hours in the fumes I get a slight headache that goes away after 1/2 hour in fresh air. If I open two doors for a couple of minutes, the smell goes fast (and no headache). Ian COZY MKIV #0069 Date: Thu, 03 Sep 1998 11:49:06 -0400 From: bil kleb Subject: Re: Fwd: COZY: Intrument panel stiffeners ribs and other Qs Ian Douglas wrote: > > Switch to Aeropoxy, it [...] has next to no smell. > [...] > After 12 hours in the fumes I get a slight headache that goes away after 1/2 > hour in fresh air. [...] smell isn't the issue. if you don't use a forced air system or wear a carbon filter respirator when working in such an enclosed space you are just begging to be relieved of your building dream! -- bil Date: Sat, 05 Sep 1998 08:15:56 -0700 From: Frank Johanson Subject: Re: Fwd: COZY: Intrument panel stiffeners ribs and other Qs Ian please don't do that!! We don't need more bad news to hurt everyone and give builders a bad reputation. Carbon monoxide has no smell either but it will KILL you. I am not an M.D. but if the percentage of O2 in the room reaches to small a percentage you will pass out , and if not found soon , well maybe we could use your plane as the coffin. The epoxy will also cause cumulative damage to the body. Again, you don't feel the effects until it is too late and and can't be repaired , DO NOT ruin your life. I would like to meet you some day over good times and finished planes. Best wishes Frank Johanson bil kleb wrote: > Ian Douglas wrote: > > > > Switch to Aeropoxy, it [...] has next to no smell. > > [...] > > After 12 hours in the fumes I get a slight headache that goes away after 1/2 > > hour in fresh air. [...] > > smell isn't the issue. if you don't use a forced air system or > wear a carbon filter respirator when working in such an enclosed > space you are just begging to be relieved of your building dream! > > -- > bil Date: Tue, 8 Sep 1998 08:33:30 -0500 From: Tom Brusehaver Subject: Re: COZY: MGS epoxy Lee Devlin wrote >Latex and vinyl gloves work fine until you get your first reaction. I did >about 50 layups before I got my reaction while using latex gloves. The best >protection is to get a pair of butyl gloves which are around $12 and then use >the disposable latex gloves to protect them. Barrier creams remind me of the >emperor's clothes. I have used ply-9 since the begining. I use latex gloves when I have big cuts on my fingers, and really prefer the ply-9. I have used latex gloves on other projects (canoe, dingy, helping others), and have found that the gloves do tear! Suddenly you are without protection at all. I imagine the ply-9 wears thin in spots, and it is tough to remember to work it into cuticles, etc. Usually the cleanup is tough in the areas where you forget to work it in. I have used a product called Invisible Gloves (I think), a white cream. I didn't like it at all. My 2cents From: "Melchinger, Klaus" Subject: COZY: L285 Date: Fri, 11 Sep 1998 08:14:10 +0200 Hi folks, I'm not sure, if anybody mentioned it already, but as I'm living in Germany I just wanted to let you know, that you can get specific information about L285 and other products of Scheufler company at: . Their e-mail address is mgs@mgs-online.com. Best Klaus Melchinger Daimler-Benz AG Informationsmanagement Funktionalressorts & Konzernführungssysteme (IO/F) HPC 0233 Telefon: +49 711 17 93359 Fax: +49 711 17 959249 Mail: klaus.melchinger@str.daimler-benz.com Date: Sun, 13 Sep 1998 15:59:49 -0400 From: John Millington Subject: COZY: The final word on Epoxy? I am waiting for my foam to arrive from Aircraft Spruce and hope to start Chapter 4 after making a pretty darn good lookin "bookend". I also was at a local EAA Chapter (#70) Fly-In, and got six years of back issues of "Sport Aviation" for only a few bucks. If I can find any info on Cozies or any of its' cousins, I have to read it. Anyway, I really just wanted to make sure that I understand the "epoxy issue". I am set-up for, and have been utilizing the MGS 285 epoxy and really find it great to work with. I just want to make sure that I can use this epoxy for ALL of the epoxy needs in constructing the airframe. I used the MGS 285 to make the confidence layup as well as the book-end and have had a pretty good time with it. The reason that I am even asking is that the plans explicitely state to use 2427. Would I be wrong to say that I can use the MGS 285 for all of these types of utilizations? One more item, that I have to make a comment about..... I have learned so much from monitoring this forum for the last month or so and that I am sure that my plane will be better quality due directly to the experience that you guys all share here. Thanks. Thanks, ( #706 will be started this week.) J. Austin Millington Date: Tue, 15 Sep 1998 21:33:18 -0400 From: "Marc J. Zeitlin" Subject: Fwd: COZY: The final word on Epoxy? John Millington wrote; >.....the plans explicitely state to use 2427. Would I be >wrong to say that I can use the MGS 285 for all of these types of >utilizations? Any of the approved epoxies can be used for any layup in the aircraft. The only time you may want to use a specific epoxy (other than your default) is for the inside of the fuel tank - you want to make sure that whatever you coat it with is fuel resistant. -- Marc J. Zeitlin                     marcz@ultranet.com 3 Sweetbriar Way                  http://www.ultranet.com/~marcz Acton, MA  01720                 http://cozy.canard.com/ Date: Tue, 15 Sep 1998 21:31:01 -0400 From: "Marc J. Zeitlin" Subject: Fwd: Re: Fwd: COZY: Builders' Weights on Marc's Website Joseph H. Hart IV wrote; >Does anyone know if MGS 285 is lighter than the other approved epoxies? I >haven't seen any discussion of this on the list but, if it is lighter, it could >make a substantial difference in final useful load. Very doubtful. I would be extremely surprised if the specific gravity (or density) of these epoxies was more than a couple of percent different than any of the others we use. >P.S. I hope that I haven't been abusing my membership on the list by posting >so many questions lately. I am sure that I will become more confident in short >order and no longer be so reliant on all of you. In the meantime, thank you >for your patience. Geez, Joseph - that's what the list is for :-). Don't apologize for using something in the manner in which it was intended - especially since you've been reading the archives and checking the reference material on the web pages! -- Marc J. Zeitlin                     marcz@ultranet.com 3 Sweetbriar Way                  http://www.ultranet.com/~marcz Acton, MA  01720                 http://cozy.canard.com/ From: Epplin John A Subject: RE: COZY: Epoxy Brush Date: Tue, 17 Nov 1998 10:58:26 -0600 I'll add .02 cents to this. I use a Tupperware type (Polyethylene, maybe?) square shallow bowl with snapon tight fitting lid. Toss in brush, scissors, squeegee and parts of rotary cutter. Not sure about MEK, seems there has been some data lately indicating that the stuff is somewhat hazardous. I use acetone, not something you want to sniff all day but so far have not heard to many horror stories about it. It evaporates very fast, need to keep the cover tight on the container. I get by several months without changing the acetone, it does eventually get so much epoxy in it starts to gel. The real payoff here is the shedding hairs. it seems after a couple of uses the brush quits shedding. John Epplin MK4 #467 > -----Original Message----- > From: njugolini@efdsouth.navfac.navy.mil > [SMTP:njugolini@efdsouth.navfac.navy.mil] > Sent: Tuesday, November 17, 1998 10:06 AM > To: cozy_builders@canard.com > Subject: COZY: Epoxy Brush > > Here is a tip I thought I would share with other builders. > > I used to buy bunches of epoxy brushes. Now, I have used the same 2" > brush > for 2+ months. > > I just sacrificed a quart mason jar, filled it 1/2 full with MEK and cut > part of the 2" brush handle off (so it would fit into the jar and not > crush > the bristles when capped. > > After your glass work (even it the epoxy start to jell) put the brush into > > the jar, cap and shake. When you are ready to use the brush, take out and > let the MEK evaporate and your are ready to use again. An added benifit > is > all the loose bristles work thier way out and my layups no longer have > those pesky thing showing up. > > Now, I go occasionally to Home Depot to buy a brush instead of ordering > boxes from ACS. Date: Tue, 17 Nov 1998 13:01:31 -0500 From: bil kleb Subject: Re: COZY: Epoxy Brush Nick J Ugolini wrote: > > Here is a tip I thought I would share with other builders. if they happen to read the archives, they'd already have it... ;) the following excerpts are thanks to hand-sorted archives of marc z, the unix `grep' command, and a couple cut n' pastes... Date: Thu, 13 Apr 1995 21:42:40 -0400 From: Ewestland@aol.com Subject: Re: Knife trimming tip Another idea on keeping the tip clean would be to store the blade in the same acetone you keep your brushes in. I used to throw my brushes in the freezer between lay-ups, but I now store them in a glass jar with a little acetone or laquer thinner in it. Prior to using them, I shake them out good and let them air dry for 10 minutes or so and they come out better than new - better in the sense that most of the loose bristles disappear after ther first or second use. Heat it with a hair dryer if you need it quicker and wrap the handle in a little saran wrap if the wood soaks up a little acetone - I suspect this could cut through the hand cream leaving you unprotected. Date: Thu, 18 Jan 1996 07:51:09 -0600 From: Scott Mandel Subject: Epoxy Cleanup Neat trick I learned a few months ago. Get two resealable jars. I'm talking about the glass jars with a glass lid and rubber seal between the lid and the jar, held together by a metal thing. I found some in a craft store but I think they're available elsewhere. Anyhow, fill them about two inches full with MEK. Use one to clean everything. Dunk epoxy, flox, and micro laden stuff, and use the other to store your brushes after you're done dunking. I also use my just dunked brushes to clean squegees, scissors and anyhting else I've gunked up. I've found this acually makes cleanup much easier. I use less MEK, less brushes (Three are still good as new after 2 months), and my wife no longer carps at me for leaving brushes in the freezer. I find I usually don't get much reuse from those freezer brushes anyhow. This has been a winner for me all the way around. Thanks go to, Jim Marshall (a fellow Texas Cozy builder) for showing this to me. Date: Sat, 1 Jun 1996 18:41:38 -0400 From: StetsonE@aol.com Subject: Re: COZY: MEK & BURP I've only used MEK to clean brushes and my good fiberglass shears. For brushes, keep a small amount in a baby food jar or something similar. Wipe off as much epoxy from the brush as you can with a paper towel, swish the brush a few times in the MEK and dry the brush with another paper towel. A little MEK on a paper towel will adequately clean your shears. Use adequate hand protection - MEK appears to go right through latex gloves. Wear a carbon filter mask if possible. From: Howard Calk Subject: RE: COZY: Epoxy-Brush in the freezer Date: Wed, 1 Oct 1997 10:31:11 -0400 I keep an empty glass pickle jar (any jar will do a metal lid works best) which I put in some solvent (I use acetone). At the end of a lay-up I dip my brushes in the solvent and clean them as you would a paint brush then wipe them off well with a paper towel. You can get several uses from the brush using this method and the brushes will be almost as good as new after the cleaning. I put the lid on tight and save the used solvent in the jar until it gets too dirty then I throw it away. From: Lee Devlin Subject: COZY: Epoxy brush preservation Date: Wed, 1 Oct 97 11:13:40 MDT > I keep an empty glass pickle jar (any jar will do a metal lid works best) which > I put in some solvent (I use acetone). I prefer to use a salsa jar which is tall enough to store the brushes with the lid on. I also use MEK which is slightly better at disolving epoxy and doesn't evaporate as readily. Just store your brushes in the jar with about 2 inches of solvent on the bottom and the lid secured. The brushes get better with each use in that they stop shedding bristles. I lost count as to how long they last. Date: Wed, 01 Oct 1997 15:50:00 -0400 From: Jeff S Russell Subject: Re: COZY: Epoxy brush preservation Lee, I do the same but with laquer thinner. MEK can burn skin, eyes and has a low flash point (not good) but I use some on epoxy primer that's cured on my primer gun. Food for thought (salsa and brushes :-) -- bil Date: Tue, 17 Nov 1998 10:14:17 -0800 (PST) From: Chris Boultinghouse Subject: Re: COZY: Epoxy Brush ---njugolini@efdsouth.navfac.navy.mil wrote: > I just sacrificed a quart mason jar, filled it 1/2 full with MEK and cut > part of the 2" brush handle off (so it would fit into the jar and not crush > the bristles when capped. For those concerned about the safety of MEK or acetone, regular white vinegar (high-acid pickling vinegar) will dissolve epoxy. Even *cured* epoxy. It doesn't work as fast as the other solvents, and it is a bit stinky, but it is safe and cheap. I even use it to clean epoxy off my plastic-topped workbench. Just pour it on, let it sit for a while and peel the epoxy off. == Regards, Chris Boultinghouse Austin, TX _________________________________________________________ DO YOU YAHOO!? Get your free @yahoo.com address at http://mail.yahoo.com Date: Sat, 5 Dec 1998 18:28:59 -0500 Subject: COZY: Epoxy info- MGS L335 and L285 From: dhill36@juno.com (Dana Hill) Hi Cozy Group, For anyone using the MGS L335 or L285 epoxy, I received the following from the R&D Dept. of MGS Company in Germany re: change in color of the hardeners and cure time in a cold shop. Thought it might be of interest: Dana Hill Cozy Mk IV #676 Just started Ch. 5 __________________________________________________________________ --------- Begin forwarded message ---------- From: Johannes Meunier To: "Hill-EQE, Dana" , dhill36@juno.com Subject: Re: L335 for Cozy IV construction Date: Fri, 04 Dec 1998 12:50:35 +0100 Message-ID: <3667CC8A.8A85516C@mgs-online.com> References: Hello Dana, thanks for you mail of last tuesday. I always try to reply as quickly as possible, but sometimes I am all over the place, but not in my office and I only got your message to read this morning. Different color of hardener: We have a lot of different systems used in aircraft design and construction. Some of our customers use several systems in their factories and we had to experience in the past that some of their workers mixed up the several systems, for example they tried to cure L285 with hardener 335. It still cures but everyone prefers the right resin with the right hardener. Our reaction was, to colour the Hardeners 335 and 340 green from now on, to give everybody a clear reference what he/she is working with. The hardeners 285, 286 and 287 are still coloed blue, 335 and 340are green.Obviously we overcame the problems mentioned above -since we modified the colour no more mix-ups appeared (to the best of my knowledge). Curing time: 16°C is a very, very low temperature to cure the L335/340.It is also a very low temprature to work the material, it has then a fairly high viscosity and is no more fun to work with... For sure curing needs several days - if it cures at all. It might be a better choice to work at higher temperatures (min.20°C) or to mix Hardener 335 and 340. To accelerate the curing process, it is normally easy to build up some kind of a tent (consisting in plastic foil) around your part and place an electric heater in a way that heats up the tent (and the part). Of course this built up should not stay unattended, there is always a certain risk of fire with these heaters! However, you don´t need to be concerned about the quality of the layup when cured at low temperatures. It will only cure to a certain stage and it takes a lot of time, but it does not affect the quality at all. As soon as it gets warmer, the reaction goes on and on and the Tg (reference of the cross linking in the molecule) rises. The only thing you have to keep in mind is, that the heat resistance of the material is very low, when cured at these low temperatures. The material may still change its shape when exposed to higher temperatures (for example post curing). This also means the advise to wait with the finish (filler and paint) until the whole thing is post cured. If I can be of any further assistance, please let me know (although I won´t be in the office until next friday). Best regards, Johannes --------- End forwarded message ---------- ___________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com/getjuno.html or call Juno at (800) 654-JUNO [654-5866]