man Tap plastics sells some good stuff, this is what i'm using to make my lid. its 36.99 for a gallon. works so good.
TAP Surfboard Resin
A water clear, impact resistant, and UV stabilized polyester resin. When flexed, it resists cracking and crazing; it also resists damage from impact. Good wet-out with fiberglass cloth, mat, or roving. No sanding between coats—it contains no surfacing wax. Add Surface Curing agent to make a sanding coat. Thin with Styrene Monomer to make a flood coat. It has a fast cure cycle. It takes pigments and dyes very well. Catalyst sold separately.