The Gelcoat itself is slightly hygroscopic (sp?) and will therefore
absorb and retain some amount of water. If you refinish with Urethane
that issue should go away and you shouldn't need to worry about moisture
permeating the composite structure.

Good luck,

Mark

Steve Hill wrote:
After my nice flight last month in Mt. Rainier wave to 24k, my wings have
turned into a blistered nightmare on the DG-400. I probably have 2,000 small
bubbles ranging from .005 to .015" tall...I've been sanding the gelcoat down
in an effort to see if I can break through them, but I am nervous as hell if
what I'm doing is a bad idea...Is there any chemical that will remove
Gelcoat and not hurt the substrate, or is the best method to actually just
sand till ya can't sand no more???


Anyway...my thought is to sand the wings down, but then I'm not really clear
on what's going to keep the moisture from returning for good...it seems like
baking the wings is a decent idea, though for now I'm not exactly sure how
and at what temperature...Anyone's input will be appreciated...again, the
worry is that if you go to all the trouble to sand things down to bare
material, is there a way to assure that the bubbles don't come back in the
future. My plan would be to re-finish with one of the PolyUrethane
systems...So, time, temp, advice or chemicals!!!!

Thanks


Steve.