Re: How to treat plywood?
...... I'll be putting in my floor next weekend and I plan on coating the top, sides and botton with thinned polyester resin. Thinned so it can seap into cracks.
Its a good idea to protect the wood, but remember that thinning resin generally results in a weaker resin after cure. Thinned resin will seep into cracks better than straight resin, but as far as soaking into the wood, thinned and straight soak in about the same, although there may be more creep of the thinner agent, which will buy you nothing.
If you use a thinned coat, don't thin more than 20%, and follow with a straight coat. Also the best plan is to include some CSM or cloth in the coating, because straight resin (especially polyester) tends to crack easier when there is no glass to give it strength. Glass in resin is like rebar in concrete.
When glassing the recessed deck pieces installed in my Capri, I didn't bother to glass the edges, it was just too much trouble to try to glass 5/8" wide edge. But it doesn't appear that the edge will be a problem especially seeing how much resin gets sucked in the end grain plies.