Sport Today

I fixed a board crack on an old Adagio early this evening with a
fiberglass cloth patch and resin - but I think I might have used the
wrong hardener (I'm "pretty sure" it was the same as the stuff I used
last winter to re-surface another board) or maybe not enough hardener.
 Resin comes in a 1 litre can, the instructions on the can label are
in fluid oz, the hardener in ml. I put 35 drops in about 1 cup. After
I painted the patch on, I thinned the resin with about 30% actetone
and resurfaced the board while I was at it.  The board is still tacky
and the leftover resin in the cup hasn't hardened at all 3 hours
later.  I know the temperature can slow things down; its about 11 C or
50 F, but I thought the reaction was chemical and generated its own
heat.  Most of what I read cautions against the stuff going off too
fast.  Can I speed things up at this point??  It it is still gooey by
morning, what do I do?

scrape!!
first off - that sounds like Polyester resin, which melts EPS foam (that crack
you "fixed" went exactly how deep?). It also does not stick particularly well,
and yellows with exposure to sun. 35 drops to a cup sounds marginal, but might
go off eventually. If the catalyst was old, it may not. Yes, Polyester will
produce heat as it cures, but this heat dissipates rapidly from a thin film -
which is what you appear to have produced by thinning. And speaking of
thinning: 30% is a lot!
Eva

Thanks Eva
Yep, bad news is "polyester resin" halfway down in the fine print on
the back of the can. I didn't know there was more than one kind, it
said for marine applications. I'll search old posts here for more
info, there must be similar past goofs.

Good news (I think) is that it hardened up after 12 hours.  The cracks
were two surface 'skin' cracks on the starboard rails in line with the
footstraps - seemed to be a bit soft here too when I was examining the
cracks, but it was hard to say if that was just loss of integrity from
the crack, there wasn't any big voids, so I didn't bother with filler.
 The patches just went over the surface. The port side rail was always
hard, but likely I hit the chop with more impact on starboard tack.  I
gently pushed on the patches this morning, I couldn't feel any obvious
voids from melted foam.  Maybe I was lucky.

Yellowing is no problem on a 1990 - ish board.  I was just hoping to
get another few months out of it - 2/3 of the people consulted on the
beach said "throw it out, opportunity to get a new board", the other
1/3 said "easy fix".