How to Repair Fiberglass Canoe Hull

Canoes are commonly constructed out of fiberglass, a strong and durable material. Fiberglass does not dent like metal does, but when it's hit hard enough it can break or crack. It's fairly common when canoeing to hit rocks that are unseen on the surface. But damaged fiberglass can easily be repaired to original strength if handled correctly. All supplies needed for fiberglass repair can be found at your local marine supply store.

Things You'll Need

  • Respirator
  • Die grinder
  • Rags
  • Acetone
  • 1.5 oz. fiberglass mat
  • Razor knife
  • Polyester resin
  • Catalyst
  • Small bucket
  • Stir stick
  • Felt roller
  • Air roller
  • Palm sander
  • 200-grit sandpaper
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Instructions

    • 1

      Put on a respirator and grind the outside of the damaged hull using a die grinder. For a crack, grind directly on the crack, forming a grove. Using the die grinder, bevel the walls of the groove so they are gradually tapered. Grind any loose or broken fiberglass down until you reach smooth and solid fiberglass.

    • 2

      Clean the surface of the repair using a rag and acetone.

    • 3

      Cut the fiberglass mat to the size of the repair using a razor knife. Cut the first layer so it fits flat in the bottom of the grinded area. Cut six more layers of mat, with each layer a quarter-inch bigger than the previous one.

    • 4

      Mix the fiberglass resin with the catalyst in a small bucket, following the directions on the containers. Use a stir stick to mix the resin.

    • 5

      Wet the surface of the repair with the resin mixture using a felt roller. Apply the smallest layer of mat in the center of the repair. Saturate the mat with the resin mixture using the felt roller. Remove any air trapped under the mat with an air roller. Repeat this process for each layer until they are all applied to the repair. Let the fiberglass harden for 45 minutes, or until it's hard and cool to the touch.

    • 6

      Grind the inside of the repair with the die grinder, following the same process you did on the outside. Wipe the area clean with a rag and acetone.

    • 7

      Cut another three layers of mat to cover the inside of the repair. Each layer should be a quarter-inch smaller than the previous one.

    • 8

      Apply the three layers of mat, following the same process you did on the outside of the repair. Let the fiberglass harden.

    • 9

      Sand the fiberglass smooth with 200-grit sandpaper and a palm sander.