Mike,
Brian is correct that the strength odf the repair might be compromised,
but if you scrub the inside and lay in as much glass as you had to grind
off to get to where you want the gelcoat, it should be fine.
If you are paranoid about the gelcoat/epoxy bond then go get a little
vinylester resin and do a wet coat of that on the epoxy before applying
the gelcoat. The vinylester will bond to both the epoxy and the
poylester, but polyester does like to stick ot very much.
Matt Colie

Bonasa wrote:
This is my first shot at a fiberglass repair and it didn't go quite as
smoothly as it showed in the book. I'm stumped about what to do next and
hope someone on this group has either done the same thing or can tell me how
to fix this.

I had two good size holes in a 22' sailboat to patch. The holes are shaped
long and narrrow, cracks in the hull that I cut out and laid in epoxy resin
and fiberglass. I followed the instructions in the book by Don Casey on Deck
and Hull Repair. I worked from the inside, grinding a 12:1 bevel and laying
down increasingly larger patches of epoxy resin soaked fiberglass.

The part I screwed up is the plastic I had laid up against the hull for the
first coat of gelcoat was not reinforced well enough. When I was squeezing
the patches to get the air bubbles out I pushed too hard. Taking off the
backing the fiberglass has set up perfectly except I pushed it so some of
the fiberglass now bulges beyond the exterior of the hull itself. Naturally
the gelcoat I had applied before laying down the fiberglass just fell out.
By the way I talked to the technicians at West Systems who assured me that
the polyester resin would stick to the epoxy patch.

Now I'm not sure what to do. My first impulse is to sand (scuff) the
fiberglass down past the hull and lay on gelcoat, then sand the gelcoat
flush with the hull. Would this work or am I just ruining the patch job? I'd
rather not use paint so any suggestions that would allow me to use gelcoat
(I've already got it) would be appreciated. Thank you in advance for any
help!

Mike