From: cdenk@ix.netcom.com
Date: Mon, 6 Apr 1998 19:30:39 -0500 (CDT)
Subject: Re: COZY: finsihing

Don Ponciroli asked that I make some comments on finishing my Cosy Classi=
c. I=20
felt there were more builders that would be intrested, sorry its so long,=
 but=20
I thought it was all pertinant.=20

COMPOSITE AIRCRAFT FINISHING TIPS
Although this is primarily a tool and material list, there are=20
many tips included.
1)	TOOLS
a)	Power
i)	Dremel Tool with assorted grinding wheels, cutters,=20
sanding drums. The router base is excellent along with a=20
straightedge and =BD" sanding drum for trimming trailing=20
edges, and with a flat grinding wheel recesses like the=20
landing brake can be contoured, and the flat stone when=20
set flush with the bottom of the router base can flush=20
off nubbins and micro or flox on foam. I have 2, one is=20
now home, the other at the airport, but during=20
construction, it was a real time saver to have them set=20
up with different cutters. Dremel will for about $30=20
maximum repair a broke tool. The slide switches are=20
susceptible to dust, and many times a blast of compressed=20
air while moving the switch will solve the problem. I=20
purchased a 1.5" sanding disc for the dremel 8 years ago,=20
it is great, but I haven't seen one for sale in years. If=20
anyone sees them please let me know.=20
ii)	DA sander (compressed air orbital or rotary 6" dia.=20
Prefer Detroit brand) with PSA (self adhesive) discs in=20
220 and 80 grit. Use only in orbital mode, do not use=20
rotary mode on fiberglass since it cuts quick. I only=20
used to scuff or where I wanted to remove fiberglass. Use=20
with wool and foam buffing pads for polishing paint to=20
high gloss. Needs at least 5 SCFM compressor.

2)	Measuring Tools
a)	Wallpaper hangers 7 foot extruded aluminum straightedge.=20
Though used more during earlier construction, very useful=20
for ensuring a surface is flat.
b)	=BC" x 2" x 3" aluminum bar. Same a above, when edge dragged=20
with moderate pressure of micro surface, it will leave black=20
marks on high spots. Shine light from behind to see low=20
spots. After sanding the high spots as much as possible,=20
Using the various methods to detect low spots, I usually=20
would put small tick marks at the extents of the low spots,=20
then connect the tick marks as a guide when spreading more=20
micro. Different color pencils help distinguish the current=20
marks, when you get many layers.
c)	12" steel rule, like comes with combination square. On edge=20
(the back of a hacksaw blade also) when rocked ove a curved=20
(even slightly) will click if not perfectly rounded. Also=20
one can compare the rate of divergence on both side of the=20
contact point to tell if the rate of curvature is uniform.
d)	Various flexible metal (steel and aluminum) and plastic=20
metal strips. Must be perfectly straight. When bent with the=20
flat side down around a curve, gaps will be evident at low=20
spots.
e)	Water and a sponge or rag. Wipe the area with a damp sponge=20
with a light shining toward you. The thin layer of water=20
will reflect the light, showing defects.=20

3)	Filler Application Tools
a)	Various size polyethylene squeegees, mostly used 3" x 4",=20
used by Auto body shops for Bondo (Polyester filler). Can be=20
bent between 3 fingers for curves.
b)	2" x 3" x 1/8" Rubber squeegee for smaller areas.
c)	6" rubber squeegee, Wicks # 14-4546, Best for leveling micro=20
on large surfaces, less tearing. Can be bent with hands or=20
fingers for curves. Go at 90 degrees for leveling, usually=20
will find one direction or the other will result in best=20
surface. Vary the angle to regulate the thickness. With=20
moderate pressure can fill pinholes with thin micro,=20
removing excess material. Use 50/50 micro and "Cab-O-SIL"=20
Wicks # M5 to consistence of shaving cream for best results=20
in filling pin holes. Its too heavy for all but last coat of=20
filler. I found that for larger areas, it might take 6 coats=20
of filler to get the contour and smoothness I was happy=20
with.

4)	Sanding Tools
a)	Oak or other hardwood (well aged and stable straight, and=20
not softwood) 5/4 (1.125" thick) x 1/3 sandpaper sheet wide=20
x 4 sandpaper sheet lengths long (exactly size). Mill with a=20
router, near full length finger grooves on edges. Glue 80=20
grit paper with 3M Super 77 spray adhesive. When the paper=20
is dull (keep it sharp for best results in leveling) clamp=20
one end to your bench, use wide putty knife and heat gun to=20
remove paper, one extra swat with knife and heat to clean=20
up, and glue new paper. Use mostly with 45 degree strokes=20
several one way, then several the other. In the early stages=20
of leveling a surface, Use to find high spots, use next item=20
down with 36 grit for faster action. Needless to say, STOP=20
as soon as the glass is encountered. This is more difficult=20
today with the clear epoxies. The Amber color of Safety=20
Epoxy would give good warning.
b)	2 Sanding boards for 2.75" x 17" sand paper sheets with=20
handle similar to wood plane. These are the work horse=20
tools. Early coats of micro are sanded with 36 grit/80 grit,=20
and final with 80 grit/220 grit. These have lightly padded=20
surfaces, and quick release spring clips for the paper. They=20
will do a moderate job of leveling, but unless the paper is=20
glued to a hard flat surface, it will leave a wavy surface.=20
Use at 90 degrees, several strokes each way if possible.
c)	The whole sheet sanding spline on the Ez instructions.=20
Mostly used with 220 grit for final sanding.
d)	Various small sanding blocks (concave and convex)=20
Woodworkers Supply # 808-379 and 810-537, about $4 each set,=20
1-800-645-9292
e)	Exacto knife u-shaped rounded blades for inside corners,=20
will nibble at micro. Sharp wood chisels also, both work=20
good when epoxy is at knife stage.
f)	Several flat sanding blocks, the type where you peal up the=20
rubber top, exposing points to grip the sandpaper.
g)	Make your own sanding blocks. Glue or wrap around. I have=20
used everything from hot wired foam, =BD" EMT steel thinwall=20
electrical conduit to 4" plastic drain pipe. Use your=20
imagination.

5)	Filling Materials
a)	West 105 resin (gallon), 205 Fast and 206 Slow hardeners=20
(quart). Buy 2 sets of pumps. The fast will cure if mixed in=20
the morning, can sand in the late afternoon, and put another=20
coat on. The slow will cure overnight and is sandable  the=20
next morning. The fast will go Bang (exotherm) if mixed in=20
large quantities, and gets sticky fairly quick. Best results=20
will be with the slow, but the time is a real advantage.=20
When mixing be consistent with the ratio of micro to epoxy,=20
otherwise the richer in epoxy will sand harder, making it=20
difficult to make it level. I used 4 oz paper cups, but have=20
since changed to coffee scoops.
b)	Micro, the usual stuff. As mentioned above CAB O SIL for the=20
last coat squeezed hard to only fill small depressions.
c)	Flox, also the usual stuff, all leading edges must not be=20
micro, but flox to prevent chipping from bugs and other=20
debris.
6)	Sanding Materials (Probably will have some left, but this will=20
be least costly).
a)	For Air sander: 1 box ea. 80grit and 220 grit
b)	Sandpaper sheets: 1 sleeve ea. 80 grit and 220 grit
c)	2.75" x 17" sandpaper: 1 box each 36 grit, 80 grit, 220=20
grit.
d)	20 sheets 320 wet/dry paper for wet sanding primer
e)	30 sheets 1500 wet/dry for color sanding if you paint will=20
allow.
7)	Primer Material
a)	Tenaco epoxy primer, Viking Paints, Inc. 100 W. 78th Street,=20
Richfield, Minn. (Near Minneapolis), phone 614-866-1212. 2=20
Gallon unit of gray and 1 gallon (1/2 gallon epoxy, =BD gallon=20
hardner) of zinc chromate bright yellow. Use the gray for=20
main filler of fine scratches, can add some micro, say 4=20
fluid oz. Per quart. Add gradually, sieving through paint=20
strainer (the paper cone type) with much stirring to prevent=20
lumps. Then spray a thinned (lacquer thinner 1 to 4 primer)=20
light mist coat, should flow into scratches pits and other=20
defects. When wet sanding with 320, aim at removing all=20
yellow! If you decide to leave some in defects, they will=20
show through the finished paint, but they may be at an=20
obscure location. Note that some catalyzed systems require a=20
time after mixing and before applying. This is to allow some=20
thinners to flash off. The material evaporating can cause=20
pinholes. Most of the problems with pinholes is=20
understanding whats happening. The pinhole starts with a=20
lean layup (which for weight reasons is good). The pinhole=20
is a very small crater, with a very smooth waxy surface.=20
When sanding to scuff the fiberglass surface these little=20
craters keep their slick surface. If the crater is small=20
enough, or the paint material surface tension allows, the=20
paint will bridge the crater, and you may be home free, But,=20
when you sand, you may break the top of the bubble creating=20
the notorious pinhole. Usually the pinhole is small enough=20
that if your successful filling once, that's good. Sometimes=20
its possible to rub in a viscous material, but the real=20
trick  is to see them and deal with them.=20
b)	Do Not use any lacquer base primer surfacers, they do not=20
provide an adequate bond to the top coat, and flaking=20
pealing, and chipping will occur.
c)	Fine filler =96 I have lately used a fine ground auto body=20
filler (polyester)bondo type that takes the place of the=20
lacquer putty that used to be used to fill isolated=20
scratches. I have heard lately don't use polyester, I don't=20
know, using very small quantities. Its neat in that it cures=20
in 5 minutes, and sands readily.
d)	Material just under the color coats, and applied immediately=20
prior. Called primer, sealer, bond coat, etc. To enhance the=20
adhesion of the top coats, generally an epoxy or other=20
catalyzed material, do not use lacquer base here either.=20
This material will be part of the system prescribed as part=20
of the top coat paint. Follow all exactly. For my Deltron, I=20
used the Ditzler DP50/DP401 light gray epoxy primer. It gets=20
thinned, and then just a light coat is required, color=20
hiding not required, but wet enough to flow out. There are=20
minimum and maximum times until the top coat is applied.
e)	Top Coats: I used Ditzler Deltron (DAU series). No=20
clearcoat, pearls, metallics etc. for the white. The Plain=20
Deltron is very easy to blend for repairs. Sand the blend=20
area with 1500 wet paper, paint, spray reducer on blend area=20
to melt overspray and orange peal. When cured the next day,=20
sand the blend area until a uniform dull color, and buff out=20
per below. If another paint system is considered, verify=20
that the blending is possible. Imron is very difficult if=20
not impossible to blend, and many others are also. You will=20
find it necessary to touch up due to hanger rash,=20
modifications, and just routine wear and tear. My trim=20
colors are the Deltron clearcoat system, which provides more=20
brilliant metallic. The trim can be blended, but also these=20
are small areas. The trim should be masked to both sides of=20
the dividing line so there is only one thickness of paint=20
everywhere, where possible. On exception usually is the=20
registration number. For the interior, flattener and texture=20
additives are available to modify the gloss and texture. My=20
instrument panel cover is dull, texture Deltron black, and=20
the instrument panel is matte slate gray Deltron. The=20
interior is Ditzler acrylic lacquer off white that is matte=20
from applying slightly dry and not buffing. It is moderately=20
durable, if I was doing it again, I would use Deltron.=20
f)	Painting: I used a 1 hp. 4.6cfm compressor and Binks #370A=20
internal mix spray gun (not HVLP). The gun is the largest=20
air flow I could find for my compressor. If you have a=20
larger compressor, I would suggest a gun with higher air=20
usage. I have had zero experience with HVLP equipment, but I=20
do know the demonstrations I see at OSH are not anywhere=20
near the volume of paint flow needed. The Deltron dries dust=20
free quickly, and most of the overspray is dryfall as dust.=20
The Deltron prefers fairly heavy flow, and make sure your=20
outfit (HLVP or conventional) can put out enough paint flow.=20
Have a strong light at a shallow angle to the sprayed=20
surface, with our eyeball at the opposite side from the=20
spray pattern. You can now see the paint surface immediately=20
after the spray pattern passes. The first coat wants to be=20
50% coverage (the under color should be somewhat visible),=20
and it may not flow out, wait until you can touch the=20
masking tape without lifting fresh paint before starting=20
that area of the next for all coats. Most of the time unless=20
it's a small area, by the time you get done at one end, the=20
starting end will be ready for the next coat. The second=20
coat should cover and start to flow out. The 3rd and 4th or=20
so coats should flow out. While watching the flow out with=20
the light behind the spray, you can see quickly whether to=20
go faster or slower. If its not flowing out 4" behind the=20
spray, go slower, but if you go too slow, runs may result.=20
The Deltron is very forgiving, if its not running in 5=20
minutes, its, not going to. The worst thing is too little=20
paint when done, then you will rub through. If you do get a=20
run, it is possible to tape a loop of masking tape, sticky=20
out, and gently touch the fresh paint. The resulting mottled=20
surface usually will flow out with additional paint, and=20
with some sanding will disappear.=20
g)	Trim: All of my outside lettering (from the 12" Registration=20
number to =BC" fuel tank capacity) is the same paint system=20
(Deltron) with paint masks. Most of my interior lettering is=20
prespaced vinyl lettering. Prespaced means the lettering=20
comes assembled between 2 pieces of release paper, exactly=20
as your copy shows. I usually would use my word processor or=20
speadsheet (including fonts, size and spacing) to make a=20
sample, hold in location, and if OK fax or mail. Both the=20
paint masks and lettering came from Aerographics, 1-800-336-
9633. To apply, trim the release paper to minimum size, use=20
a masking tape hinge to hold a one edge in exactly in=20
position, hinge up and peal off the bottom release paper,=20
squeegee down, remove the top paper. For more durability,=20
spray coat with "KRYlON" Clear spray. Careful, don't use=20
catalyzed coatings, they will damage the lettering. For=20
masking the top coats, use the fine line (vinyl ??) masking=20
tape next to the fresh paint, and paper masking tape on top=20
that to hold the paper. If using newspaper, caution one edge=20
is perforated by the press paper feeder, run a strip of=20
making tape over the little holes to seal.=20
h)	Finishing the top coat: Sand everything to a dull uniform=20
finish with 1500 wet paper. Glue paper to a small (2" x 2")=20
wood block. With sharp paper this can be used to flatten=20
runs, and the masking ridge between 2 colors. Buff with an=20
orbital wool pad using 3M Imperial Microfinishing Compound=20
#051131-06011, then Buff with an wool pad with Mequiar's=20
Show car glaze, then buff with a foam pad using Liquid ebony=20
#27 from Cleanbright Manufacturing Co., 1324 Herschell st.,=20
Bronx, Ny, 10461. Its advertised as a wheel mark remover. Do=20
not use a rotary buffer, they cut too fast, gouge, burn, and=20
unless very artfully used cause more damage. The Deltron=20
polishes to a very high gloss quickly. The hardest will be=20
the sanding. Finish with a good automotive paste wax.=20
Annually I go over with lightly doing the above, except for=20
the 1500 sanding.=20

Happy Finishing, take your time, borrow from a local body shop an=20
old hood or trunk lid and practice. =20