Arguably, the heaviest part of a board is the resin. It's heavy and there is a bunch between lamination, hotcoat and glosscoat.
I was hotcoating a board tonight, normally I mix up about 2 oz more than I'll need. Tonight I pushed the excess epoxy back into the bucket.
When you push epoxy around it foams, but typically subsides.
The epoxy I used tonight cured all foamed up. It displaced at least 20 times the volume as the residual I normally have.
I'm not sure what to do with this information, but if I couls use 1/20 the norm, I could cut back on weight significantly.
Normal 2 oz residual:
Foamed 2 oz residual: