How to Repair a Gelcoat on Boats
Gelcoat is the thin, glossy surface on your fiberglass boat's hull. Gelcoat is the first surface into the mold when a fiberglass boat is being built. It is sprayed in to form a layer only a bit thicker than the walls of a plastic trash bag. Some damage, including collisions, requires a full fiberglass repair. Fortunately, the most common type of damage that gelcoat sustains is crazing, in which the gelcoat surface begins to break down from exposure to the sun, water and the oxygen in the air.
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Things You'll Need
- Palm sander
- 220 grit sand paper
- Glazing compound
- Small bladed putty knife
- Paint
- Wax
Instructions
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If the gelcoat is cracked, sand the area with a palm sander and 220 grit sand paper. The 220 grit sandpaper is sufficiently fine that sanding marks will be difficult to detect.
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Pack glazing compound into the cracked gelcoat with a small-bladed putty knife. Be sure to add enough glazing compound to the crack that the glazing compound rises above the level of the crack.
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Allow the glazing compound to cure for at least 24 hours, then sand it down using 220 grit sandpaper and your sander until it's level with the surface of the hull. Rinse the sanding dust from the repair and, if touch-up paint is required, apply the paint then wax the surface.
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Tips & Warnings
For more extensive damage, but not damage that penetrates the fiberglass, you can substitute 2-part marine epoxy for the glazing compound.
Read and follow the precautions on the glazing compound container.
