Prepare the Surface

• Hand-sand the entire surface of the fiberglass with 320-grit (very fine) sandpaper. Start at the top part of the area and work your way down, using quick, light strokes. Sand it just enough to buff off the shine. Follow up by washing the whole thing in muriatic acid. Wear rubber gloves and rinse it well with water. Let it dry completely.
  
  

Prime

• Use a good oil-based primer to get a smooth, even surface on which to apply the paint. The primer should be applied with a spray gun on a light setting. Spray a very thin, even coat, let it dry, then repeat. It's better to use numerous light coats than one heavy one. Use as many coats as are necessary to get complete coverage (generally, three or four).
  
  

Paint

• Use a good epoxy-based paint. Apply with a spray gun, diluting the paint if necessary with paint thinner. Apply the paint in very thin, light, even coats, taking care not to allow drips or streaks to form. Keep the sprayer moving at all times. Let each coat dry thoroughly according to instructions before applying the next coat. Plan on putting on at least three or four coats, maybe up to six.