I make my molds out of 2 halves of foam and then cover each half of the foam with glass and after it cures I prime and paint it so it's nice and smooth. I use dowels to hold the two together for making the cowl. Then I start with 400 grit wet paper and finish with 1500 grit. Then I wax it with 3 coats of turtle car wax in a can. Last I use a Preval sprayer to spray on the Evercoat Mold Relase Agent. It makes a sort of rubbery layer between the mold and the glass your making the cowl out of. I alway make sure I get plenty of the spray mold release agent on the mold and let it sit overnight to dry. You will be able to see when it's dry because it acts like a glossy clear coat and makes the sanded paint glossy again like it wasn't ever sanded. After the cowl cures I seperate the two halves of the mold and the cowl just needs slight sanding at the seams. Be sure to go around the edges of the foam with glass where they go together so the mold release will be there too.
Barry
www.canopyrailsforwarbirds.com