How to Paint on Top of a Gelcoat

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Gelcoat is a type of resin with a high pigmentation content to give it color. This type of coating is used on most fiberglass boats to prevent mold. Most types of gelcoat do not hold up well to sunlight and weathering, and frequently the pigmentation fades and the surface of the gelcoat becomes chalky. One solution is to paint over the gelcoat with a marine-grade paint.

Prepare the surface by removing all teak rails, aluminum windows, plastic parts and hardware. Remove all caulking.

Clean the surface thoroughly to remove all dirt, grease, mold, mildew, rust, waxes or any other type of material. This may require several different cleansing products as each area of the surface is worked on. Use cleansers recommended by the boat manufacturer for the surface finish of the boat.

Make repairs to the surface. This includes sanding and filling holes and scratches with filler products designed for gelcoat and fiberglass repair. Often this repair process is combined with applying special primers to increase the adhesion of the paint to the gelcoat -- with sanding in between layers of primer to feather out irregularities and defects.

Spray the paint in an environmentally-controlled paint booth. Typically, the type of paint used to cover gelcoat is a marine-rated urethane paint. The painting should be done when the temperature is between 70-80 degrees and the humidity is below 65 percent. Often a good paint job will involve several coats with sanding between coats.


  • For best results, hire a professional painter.


About the Author

F.R.R. Mallory has been published since 1996, writing books, short stories, articles and essays. She has worked as an architect, restored cars, designed clothing, renovated homes and makes crafts. She is a graduate of the University of California at Berkeley with bachelor's degrees in psychology and English. Her fiction short story "Black Ice" recently won a National Space Society contest.

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