Things You'll Need
Blue painter's tape
Heavy-duty fabric drop cloth
Acrylic spray paint
Use a fine grit sandpaper. Do not use a grit lower than 400, because this may cut grooves in the fiberglass that could show in the final finish.
Do not over-sand. Stop sanding when the fiberglass feels slightly rough to the touch.
Do not use a rag in place of a tack cloth.
Unlike wood, fiberglass surfaces are nonporous, making them unsuitable for spray paint adhesion. Before you can spray paint any type of fiberglass surface, you will need to employ specific preparation techniques to condition the fiberglass to accept paint, or the finish will peel soon after application. In addition, because fiberglass is slick and smooth, you will need to use a particular application technique to promote a smooth, professional-looking finish free of runs, drips, and sagging.
Clean the fiberglass using dish soap. Rinse the surface, and allow it to dry completely before continuing.
Abrade the fiberglass to promote adhesion by sanding it with a palm sander loaded with 400-grit sandpaper.
Wipe down the fiberglass with a tack cloth.
Cover any areas of the fiberglass you do not want painted with painter's tape. Cover large areas below or adjacent to the fiberglass with drop cloths.
Apply a very light coat of primer to the fiberglass. Spray in intermittent mists to promote a professional-looking finish free of runs, drips, and sagging. Do not apply a constant stream, or you may end up with flaws in the finish coat.
Allow the primer to dry and cure for fours hours, and then apply a coat of acrylic spray paint in the same way you applied the primer.
Ryan Lawrence is a freelance writer based in Boulder, Colorado. He has been writing professionally since 1999. He has 10 years of experience as a professional painting contractor. Lawrence writes for High Class Blogs and Yodle. He has a bachelor's degree in journalism and public relations with a minor in history from the University of Oklahoma.