6. Once the fiberglass hood has been thoroughly sanded for straightness with a long board, apply a generous amount of primer. A good layer of primer (Deltron Uro Prime, in our case) usually fills in minor imperfections and/or sanding scratches. Plus, the primer provides good "grip" for the paint to adhere to. Never sand the fiberglass hood and then apply paint without using primer. After applying primer to the fiberglass hood, carefully wet-sand the surface with 400-grit paper. Using plenty of water, wet-sand using the flat of your hand rather than your fingertips. After sanding, dry and clean the surface using a cleaner such as Du Pont Final Klean.