Painting fiberglass, whether it is found on a boat, storage tank, decorative piece or elsewhere, is easy as long as it is prepared correctly. Paint tends not to stick to slippery surfaces, so roughing up the surface is critical. Using the proper coatings for fiberglass will also go a long way toward ensuring your success. Once you understand the special needs of fiberglass, the painting process is simple.
Wash the fiberglass with a scrub brush, water and dish soap.
Moisten a rag with wax-and-grease remover. Use this rag to wipe small sections of the fiberglass. Use another rag to wipe the cleaner off. Work in small sections, applying the cleaner, and removing it immediately, until you have cleaned the entire surface.
Sand the entire surface. Wet sanding works best. Sand the surface until all the shine of the fiberglass is dulled.
Wash the fiberglass again with a fresh bucket of water and soap to thoroughly remove any sanding dust.
Allow the fiberglass to dry.
Use a paint roller, brush or sprayer to apply a coat of fiberglass primer. Allow the primer to dry overnight.