How To Repair Your Boat’s Gelcoat

While loading your boat onto your trailer, you accidentally nick the bow. Or perhaps you forget to drop your bumpers when you pull up to the dock, and the dock scratches the side. Nothing feels worse than that first scratch in a new boat, but don’t worry, you are not alone, and the scratch is not that hard to repair.

Generally, fiberglass boats are painted with gelcoat, synthetic material made from polyester. Gelcoat provides the waterproof protection for the fiberglass body of the boat. Most marine supply stores sell gelcoat repair kits. The kit will consist of a container of gelcoat paste, a hardening agent, coloring additives, and mixing tools. Some kits even have a blending chart for help in matching the color of your hull.

First of all, clean the area by washing it with soap and water. Once that has dried, mask off around the scratch with painter’s tape. In order to get the best adhesion for the gelcoat, you should ream out small cracks or rough sand them. Then, lightly sand around the scratch with 220 grit sandpaper. Finally, wipe down the whole area with acetone or lacquer thinner to remove any wax that might remain.

To achieve the right color for your repair, you need to mix the gelcoat with the pigments to match the color of your boat. Taking your time with this process will ensure that your patch is less noticeable. The best way to check your colors is in natural light as fluorescent and incandescent light alter color considerably. Once you have achieved the right color, mix in the hardener. You can use this paste to fill this scratch with a putty knife. Make sure you overfill the scratch and then cover the repair with plastic wrap.

It will take approximately 24 hours for the gelcoat to cure. After it is cured, wet sand the filled spot with 220 grit sandpaper. Gradually increase the fineness of the sandpaper, at least up to 400 grit, until the repair is nice and smooth. If the repair is large or unsightly, it can be sprayed or painted with a foam brush and a thinned out version of the gelcoat. Once again, smooth out the surface. Finally, apply a marine wax over the top and buff it to a shine.

Once your repairs are done, get back out on the water. A nice day out in the boat is your reward for a job well done.

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