How to Fix Boat Gelcoat

The shiny surface of a new boat shines because it has a polyester coat over the fiberglass, that reflects light the same way that a coat of polish does. Because it is the first coat sprayed into the boat mold during the hull manufacturing process, gelcoat is the outer layer of your boat's finish, fully exposed to the elements and the bumps and dings of life on the water. It's surprisingly fragile, easily damaged and won't cure fully as long as it is exposed to air.

Things You'll Need

  • Gelcoat repair kit
  • Screwdriver
  • 80-grit sandpaper
  • Clean rags
  • Acetone
  • Styrene
  • Paint stirrer
  • Plastic spreader
  • Plastic film
  • 150-grit sandpaper
  • 220-grit wet-dry sandpaper
  • Garden hose
  • 600-grit sandpaper
  • Automotive paste wax
  • Electric buffer
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Instructions

    • 1

      Mix the pigments in the gelcoat repair kit to match the the color of your boat. No mixing is required to match white boat hulls.

    • 2

      Drag the corner of a screwdriver blade through the scratch to rough up the edges of the scratch. If the damaged area is larger than a scratch, sand the area with 80-grit sandpaper.

    • 3

      Wipe the sanding dust away with a clean rag dipped in acetone. Allow the surface to dry fully before proceeding. Wipe the area with a second clean rag dipped in styrene, to soften the existing gelcoat on the area.

    • 4

      Mix four drops of the chemical hardener from the gelcoat repair kit into 1 oz. of resin. Stir the mixture thoroughly with a paint stirrer of the type paint stores give away.

    • 5

      Apply the gelcoat paste with the plastic spreader. Cover the gelcoat with plastic film, taping the edges down with duct tape.

    • 6

      Remove the plastic after 24 hours. Sand the gelcoat with 150-grit sandpaper until it is flush with the surface. When the gelcoat is flush with the surface, switch to 220-grit wet-dry sandpaper and continue sanding while using a garden hose to run a thin stream of water across the area.

    • 7

      Feather the edges of the new gelcoat into the old gelcoat. Switch to 600-grit sandpaper and polish the repair. Apply a coat of automotive paste wax and buff with an electric buffer.