my neighbor is building a kayak using west system epoxy and he swears that “the epoxy expands slightly as it hardens like ice expands bigger than the water in an ice cube tray.” I told him i would find out. Is it true Greg? What about polyester resin, i’m guessing it shrinks a little?
Polyester shrinks about 6% if i remember right and epoxy about 2%. I hope I’m remembering right. I have the data here somewhere if anyone needs more accuracy than that. Most of the twist you see in boards is from resin twist. More so than from shaping.