Made a 3d printed mold for a little 1/4" riser for reworking my windlass mount. Layed up some glass in it after layers of mold release wax. Worked pretty good, in the end I put it in the freezer as it wasn't exactly popping out easily. It came out like an ice cube after though. I was worried molding in the holes was a mistake but came out great. I had assumed from the start I would have to destroy the mold in the end but it wasn't the case. I used polyester resin, first couple layers were 4 oz cloth because I had it, next couple pours were with 1/4" chopped strand.