A number of years ago I had a serious dose of blistering
on a Discus fuselage. I asked around several UK repair
shops and the only one who had a repair plan beyond
just sanding and refinishing was Bob McLean (the UK
DG agent) who said what he recommended was to sand
off the gel to the glass cloth, leave the exposed area
to dry off under controlled warming for a few days
until it was bone dry, then paint the surface of the
glass cloth with a thin layer of resin to seal it and
let it dry and then refinish with gelcoat and reweigh.
He did a beatiful job and we never got another single
blister in the repaired area.

John Galloway





At 23:01 02 December 2004, 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...aga
in, 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.