What casting urethane to use?

[ranchak]

I want to cast a replacement seat bottom from a motorcycle. It appears to be originally nylon(?). The new part needs to be flexible, but rigid. The seat cover is stapled to the base so it can't be as hard and rigid as epoxy or fiberglass. I live in SoCal and have been looking at some Smooth-On products: Smooth Cast 45D or Smooth Cast 300. I am not limited to this product. Other than the stated requirements, I need about a 20 min pot life, want to keep the cost under $80/gal (I know the products I mentioned cost more), hopefully available in CA to keep shipping costs down. Any ideas or suggestions?

[jetski]

BCC products in Franklin Indiana has a multitude of RP urethanes I have used for years. But the least expensive way to go and the longest lasting might be the old fashioned way of doing this by using plywood. Or using thin wood and doing your own laminating and routing to get the shape you need. Then thin coat of epoxy to make it water proof. Other wise you will be dealing with UV and the breakdown under heat and reading a lot of material and maybe not coming up with what you need. Or just laying up glass and epoxy over the old one. Epoxy some wood in and shoot the staples into that. Hope this helps.