Laying Fiberglass Over Wooden Boat Hulls

Many people find that their favorite wooden boat is beginning to show signs of age. This typically means an uneven ride or water leakage. One of the other primary indicators of aging of wooden boats is their weight. As wood absorbs moisture over time it becomes heavier and more cumbersome. These are all signs that it's time to resurface the boat and that typically means fiberglass. A fiberglass skin is the best way to give an old boat a new lease on life. Not only is it a permanent solution, it can be accomplished with a modest investment.

Things You'll Need

  • Sawhorses
  • Circular sander
  • Utility knife
  • Wood putty
  • Fiberglass-grade epoxy resin and hardener
  • Wooden or metal bucket
  • Fairing powder
  • Colloidal silica
  • Putty knife
  • Paintbrush
  • 7.6-cm-by-3-inch fiberglass tape
  • Plastic-mesh scrubber
  • Hand sanding block
  • 80-grit sandpaper
  • Lacquer thinner
  • Cheesecloth
  • 50-inch 10-oz 2-by-2 plain weave fiberglass fabric
  • Tape measure
  • Scissors
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Instructions

    • 1

      Place the target boat hull inverted in a sunny or dry place and allow it to dry for several days. Dry out older boats with a high moisture content for 30 days.

    • 2

      Invert the boat on a pair of sawhorses and inspect the surface. Look for cracks and broken edges around the seams and joints that must be filled and sealed. Use a circular sander with a 40-grit disc and remove any paint or varnish, taking it down to bare wood. Use a utility knife to gouge out holes or soft spots, patch them with wood putty and sand them smooth. Allow the sanded hull to dry for another four days.

    • 3

      Make one quart of epoxy putty for sealing joints and holes in the hull. Mix the fiberglass epoxy resin and hardener (2:1 ratio) in a wooden or metal bucket. Add equal parts of colloidal silica and fairing powder gradually until it produces a peanut butter-like putty. Use a putty knife to force the epoxy putty into joints and crevices on the hull. Let the patches and seams dry for 24 hours.

    • 4

      Mix another quart-sized batch of fiberglass epoxy resin and hardener. Use a small paintbrush and coat all the patches, plugged holes and seams on the hull with a liberal coating of full-strength epoxy resin. Allow the seams to dry for two hours and then coat them with dry 7.6-cm by 3-inch fiberglass tape. Cure the taped seams for 24 hours.

    • 5

      Scrub the taped seams on the hull with a plastic mesh scrubber and water to remove the amine blush (a waxy byproduct of epoxy resin). Sand the taped seams lightly with a hand sanding block and 80-grit sandpaper.

    • 6

      Mix two gallons of fiberglass epoxy resin and hardener (2:1 ratio). Use a new fiberglass roller and apply three coats of epoxy resin to the entire hull of the boat, spacing the applications two hours apart. Allow the epoxy resin to cure for 24 hours.

    • 7

      Clean the surface of the hull with lacquer thinner and a cheesecloth rag. Use a clean roller and apply a liberal coat of epoxy resin mixture to the entire surface of the hull. Measure and cut lengths of 50-inch fiberglass fabric long enough to extend the entire length of the hull. Drape the strips of fiberglass fabric onto the hull, with the direction of the fabric weave parallel to the long axis of the hull. Start at one gunnel edge and match up the edges without overlapping them. Use a new roller and heavily roll the fabric onto the wet surface of the hull.

    • 8

      Allow the fabric to absorb the epoxy resin for three hours. Trim all the edges and use a clean paintbrush to apply more epoxy resin to the seams and edges. Repeat the scrub-wet-drape-roll-trim-edge process in 24 hours and again 24 hours later. Apply a final coat of epoxy resin to the outer, third layer of fabric. Allow the finished hull to cure for 48 hours.