Thanks Eli, All books and tutorials that i read before starting to build s&g kayaks are strictly about use of the epoxy resin. And from my personal experience, i'm totaly agree with that. Here, where i live, polyester and vinylester resin is from 6 to 10 times cheaper then epoxy. That's why i've made some experiments. First of all, polyester resin didn't bond very well to the plywood. Which is not the case with the epoxy. Further more, when polyester cures, it shrinks much more then epoxy and tends to bend laminated plywood. When this is imposible (because the kayak panels are already glued together and kayak shape is formed) this leads to delaminating. Even if this is not happened right away, very soon delaminating will become reality and all hard work and expensive materials will be for nothing. Also, epoxy compared to other resins is very near to zero (0.andseveralzeroesherebeforesomenumber - this depends on the brand, of course) when it's about watertightness. While polyester resin (even with a gelcoat, which is hard to achieve without mould) is not so waterproof. And water that goes in couldn't go out. This leads to rot onto plywood and delaminating too. I'm aware that now on the market is a big variety of resins with different quality and designation, but i'll continue to use epoxy in s&g. Hope this helps. Jordan
Thanks Eli,