How to Paint Gelcoat on Boats

Updated April 17, 2017

Gelcoat can be found on many items, from automobiles to boats. This thin coating provides an extra layer of glossy sheen to a coat of paint. It also helps to protect the paint underneath from chipping and wear. If your boat's gelcoat is starting to peel or chip, you should consider replacing the coating to keep your boat cosmetically pristine.

Clean the entire surface of your boat with water and a mild detergent. This will help to remove loose dirt or grime. Any impurities left on the surface of the boat will be trapped and sealed into the gelcoat when applied.

Apply acetone to any loose gelcoat on the surface. This will help to remove any rough patches in the existing gelcoat, and promote a smooth new coating. Apply acetone to a clean cloth and wipe down these areas.

Mix in styrene solution to thin down the gelcoat if needed. Thinning is said to be more of an art than a science, so experiment until you get a consistency that is easily applied. Never use more than a 10 per cent styrene solution in the gelcoat, or it will begin to compromise the integrity of the mix. Thinning may be needed if the gelcoat is hard to brush on, or will not spray well through a sprayer nozzle.

Brush or spray the gelcoat onto the boat's surface. Brush application will leave brushstrokes in the gelcoat once it dries, while spray coating will leave a smooth surface. Spraying the gelcoat is generally regarded as the best way to apply the solution to get an even coverage and the best look.

Sand down the gelcoat once it is dried with sandpaper to remove any runs or marks after each coat. A fine sandpaper, around 600 grit, works best for this. Allow each coat to dry completely before you sand or add another coat. Multiple coats will ensure you have a thick, hard surface.

Clean your sprayer with acetone when finished. This will ensure that the gelcoat does not clog the nozzle and inner components of your sprayer.


Practice on an inconspicuous area of the boat, such as the bottom, until you are comfortable with your skill level. Spray guns made specifically to spray gelcoat allow the more viscous solution to spray easily.


Always use caution around harsh chemicals, following safety instructions from the manufacturer.

Things You'll Need

  • Gelcoat
  • Styrene
  • Acetone
  • Cloth
  • Mild detergent
  • Brush or sprayer
  • Fine grit sandpaper
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About the Author

Located in southeastern Kentucky, Charles Judd began writing semi-professionally in early 2005 for local publications. His work has been published in his hometown newspapers, the "Jackson Sun" and the "Jackson Times." He has many diverse interests and enjoys writing about various subjects. Charles holds a Bachelor of Science in industrial machine technology.