<br><font size=2 face="Arial">1. "Thinning the epoxy saves no
weight by evaporation. There is virtually no evaporation and no weight
loss-a big time erroneous assumption on my part. So if you mix 2
ounces of epoxy and add 2 ounces of thinner and put it all on the airplane,
you have added 4 ounces to the airplane. "</font>
<br>
<br><font size=2 face="Arial">After seeing the real question I expected
a weight increase of at least 9% (how much water in the mix). If you put
1oz (by weight) of solvent in 1 oz of epoxy, and apply it as a coating
, thin, you will eventually end up with 1 oz of epoxy. Mike, your solvent
got trapped, and now it will have less adhesion, less tensile, Compression
and flexure strength, and will now shrink slowly as the alcohol exits the
cured epoxy, over a year or so (see Wayne's answer).</font>
<br>
<br><font size=2 face="Arial">None of the solvent's listed will react with
any epoxy blend. Exotherm is negligible when applied as a thin coating,
but significant in mass. The ability to have the solvent evaporate out
of the epoxy coating is directly related to the mixed viscosity of the
neat epoxy blend and the cure rate of the epoxy. Those of you who ran experiments
with 5 minute epoxy reported bad results because of high viscosity and
fast cure rate.The high viscosity (even Mike's blend is apparently too
high) will cause a skin effect where the solvent evaporates from the surface
first, creating a high viscosity skin, then the epoxy starts to cure increasing
viscosity even more, thus trapping the solvent. Using fiberglass makes
this even worse. MIKE- in one year from now your wings will weigh less.</font>
<br>
<br><font size=2 face="Arial">So it sounds like the the Pattern Dudes of
the world need a solution. What AeroSlave can do is provide a super
low viscosity epoxy for sale. This will be 100% solids (which means NO
solvents). Chances are, as a mixed epoxy, the viscosity will be lower than
even blends with some solvent in them. This can be used to apply fiberglass
to wings or as a general laminating resin.</font>
<br>
<br><font size=2 face="Arial">How much interest would there be for such
a a product? It would probably cost about $50/ quart, $25/ pint. It would
absolutely require an accurate scale (+/- 1 gram) to WEIGH the epoxy and
hardener into the appropriate mix ratio. AND I offer no warranty, simply
because you guys are the biggest bunch of experimenters in the world, and
I cannot control, nor anticipate how this could get screwed up.</font>
<br>
<br><font size=2 face="Arial">1. Operator cannot operate a scale.</font>
<br><font size=2 face="Arial">2. Operator has a crappy scale.</font>
<br><font size=2 face="Arial">3. Operator added solvent anyway because
thats how he has always done it...since 1976</font>
<br><font size=2 face="Arial">4. Operators basement is 100% realative humidity..condensation
on the wing.</font>
<br><font size=2 face="Arial">5. Operator added "more" hardener
to make it cure faster.</font>
<br><font size=2 face="Arial">6. Operator......(enter F/U here).</font>
<br>
<br><font size=2 face="Arial">As you can see there is one common theme
to all of these possible problems, Operator, i.e. customer.</font>
<br>
<br><font size=2 face="Arial">So if you are STILL interested please respond
and Lance and I will take it under advisement.</font>
<br>
<br><font size=2 face="Arial"> </font>
<br><font size=2 face="sans-serif"><br>
<br>
<br>
Gray Fowler<br>
Senior Principal Chemical Engineer<br>
Radomes and Specialty Apertures<br>
Technical Staff Composites Engineering<br>
Raytheon</font>
<br>
<br>
<br>
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<td width=40%><font size=1 face="sans-serif"><b>"Dr. Mike Harrison"
<drmikedds@sbcglobal.net></b> </font>
<br><font size=1 face="sans-serif">Sent by: nsrca-discussion-bounces@lists.nsrca.org</font>
<p><font size=1 face="sans-serif">11/23/2007 01:57 PM</font>
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<div align=center><font size=1 face="sans-serif">Please respond to<br>
NSRCA Mailing List <nsrca-discussion@lists.nsrca.org></font></div></table>
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<td>
<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif">"NSRCA Mailing List" <nsrca-discussion@lists.nsrca.org></font>
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<td>
<div align=right><font size=1 face="sans-serif">cc</font></div>
<td>
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<td>
<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">[NSRCA-discussion] epoxy question</font></table>
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<td></table>
<br></table>
<br>
<br>
<br><font size=2 face="Arial">I have read with interest all the comments
and some of you have educated me on this issue. If I may, I will
share what I have learned.</font>
<br><font size=3> </font>
<br><font size=2 face="Arial">1. Thinning the epoxy saves no weight
by evaporation. There is virtually no evaporation and no weight loss-a
big time erroneous assumption on my part. So if you mix 2 ounces
of epoxy and add 2 ounces of thinner and put it all on the airplane, you
have added 4 ounces to the airplane. </font>
<br><font size=2 face="Arial">2. The properties of the epoxy are
changed-it becomes rubbery.</font>
<br><font size=2 face="Arial">3. Changing the properties is not an
issue regarding finishing the airplane(painting)</font>
<br><font size=2 face="Arial">4. Using thinned epoxy is fine for
applying glass cloth.</font>
<br><font size=2 face="Arial">5. I have tried MEK(epoxy thinner),
denatured alcohol, 91%alcohol, acetone. My preference is denatured
alcohol because it is the safest and most economical, I think. I
thought MEK would be the answer. It is the worst of the bunch. </font>
<br><font size=2 face="Arial">6. The best way to glass surfaces is
to thin the epoxy and apply as sparingly as possible. A way to do
that is to apply and wipe off excess with paper towels. </font>
<br><font size=2 face="Arial">7. It is almost exactly 2 ounces to
glass a wing panel complete, so 4 ounces for a whole wing. About
2 ounces for a stab. Properly done wings and stab glassed and painted
is 2-2.5 times the weight of monokote. </font>
<br><font size=2 face="Arial">8. A second thinned coat of epoxy on
the glassed wing is .75 ounces each wing panel-1.5 oz total.</font>
<br><font size=3> </font>
<br><font size=3> </font>
<br><font size=2 face="Arial">Pick your poison.</font>
<br><font size=3> </font>
<br><font size=2 face="Arial">Later,</font>
<br><font size=2 face="Arial">Mike</font>
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