There is a company near me that laminates structural wood using Vinyl Ester resin - think plywood beams four inches thick and fourty feet long, etc.. This fiberglass-type resin has half the cost of epoxy but thinning involves some producing some solvent fumes; to make an extremly low viscosity wood penetrating resin thin with up to 15% acetone or MEK, but will still get good bite with out it.
I've used these peoples #700 resin before and it performs as advertised:
700 Vinyl Ester Resin.... "Vinyl Ester resin is superior in every property as compared to all polyester resins. This product is used in high performance applications in which high-strength and maximum heat tolerance is necessary. This resin is extremely chemical resistant when cured. Similar in strength to epoxies with much increased stiffness."