Rick,
From what I understand, poly resin does not bond well to wood. Where as epoxy gets a better bite into the wood ang glass.
My brother just finished a kevlar Wee Lassie using epoxy. It was not as stiff as other kevlar boats I've seen. We then laid up a sample useing the poly resin and same schedule of kevlar/s-glass and it was conciderablly stiffer than the epoxy on the boat. If I decide to build an FRP kayak thats what I think I'll use instead of epoxy. But for glass over wood I'll stick with epoxy.
Best of luck,
Don

: Don't mean to open a can-o-worms but I gotta ask.....why epoxy instead of the
: much cheaper poly resin? I have built four s&g kayaks using top dollar
: epoxy and think I might try using the poy resin for my next project.
: Doesn't make sense that nearly all production boats are made using poly
: resin not epoxy, but yet most home builders all use the high dollar epoxy.
: comments.........