I have some new bodies at my shop, as well as some older ones. each one that I do, I wash the body thoroughly and cut it open with 180. grind the seams and fill them with vinylester filler. let it sit for a couple weeks like that before going forward. with the gelcoat "open" it will offgas considerably. I do the same with both new and old bodies. you can smell the resin offgassing once it is cut open. cheers, SRP