Gel coat is a fibreglass-based paint used in many applications such as boats, pools, tanks, surfboards and industrial pipes. Because it is made from fibreglass resin, gel coat is a protective layer as well as a paint. Commonly, after continued sun exposure, gel coat will start to fade. This can be buffed out, but it will not last long. The best resolution for a dull and faded gel coat is to repaint it. Gel coat can be covered with other paint, but you will have to prime the surface first and gel coat is the best paint for fibreglass. All gel coat supplies can be found at your local marine supply shop.
Sand the surface of the gel coat lightly, using fine grit sandpaper. In order to save time, use a palm sander on the large areas. The entire surface must be scuffed in order for the fresh gel coat to bond properly. Get in all the cracks and crevices or the gel coat will peel on the spots that were not scuffed.
Wash the entire surface of the scuffed gel coat using a sponge and water that is mixed with washing up liquid. Wipe away all the dust and residue left behind from sanding.
Mask the perimeter of the piece or any fittings with masking tape. This will protect from excess spray.
Add the gel coat and the methyl ethyl ketone peroxide hardener to the gel coat gun as directed in the manual. If it is an internal mixture gun, you will not have to manually mix the gel coat before adding it to the gun. If you do have to mix it first, do so using a small bucket and a stir stick.
Spray the first coat of gel coat in a heavy mist, keeping the tip of the gun around a foot away from the surface. This will help avoid any runs in the paint. Apply the paint in a consistent and even fashion, avoiding any heavy spots. If there are any hard-to-reach spots, you can use a small paintbrush to cover them with gel coat. Let the first coat begin to harden before applying the second coat.
Spray the second coat onto the surface so it is solidly covered. Continue to spray in a consistent manner, with the tip about a foot away from the surface to avoid any runs in the gel coat. Let the gel coat cure until it is hard and cool to the touch.