On Aug 26, 9:02*pm, Uncle Fuzzy wrote:
On Aug 26, 5:07*pm, Bob Kuykendall wrote:

On Aug 26, 4:18*pm, Uncle Fuzzy wrote:

Was Brad using a Space Heater, or a forced air gas furnace like you
have? I wouldn't think your heater would be a problem.

Brad laid up his fuselage shells at my shop, using my shop heater, not
a space heater. It's a Modine Hot Dawg 75 kbtu unit I put up several
years ago.

In the past I've used kerosene and propane space heaters, but mostly
just with quickie polyester/glass layups. Those things give me the
willies, I'm always worried about carbon monoxide poisoning.

Thanks, Bob K.

That's what I thought. *Unfortunately, that kinda' decreases the
chances that excess moisture in the air caused the epoxy not to bond
to the gelcoat.

The process the factories use has developed over quite some time.
Important factors include:
1) The exact chemistries of the gelcoat and epoxy being used. These
are chemically disimilar materials being asked to form a "permanent"
bond during curing.
2) The timing of the process. The time from when gelcoat is sprayed
and has gelled- but not cured- to when the first application of epoxy
is important to getting whatever "bond" you get between materials .

Using a developmental process with different materials will obviously
require a good bit of testing.

Another option could be to skip the whole gelcoat thing and do the
lamination of epoxy/glass/carbon directly in the mold and accept that
it will need pinhole/prime/fill and then paint. You would avoid the
time delay failure mode that gelcoat finishes have inherent to them.
They all fail- its only a matter of time till the gelcoat comes off in
sheets or chips.

FWIW
UH