How to Fiberglass a Mast

Fiberglass will significantly increase the strength of a wooden mast while adding a minimal amount of weight. Successfully applying fiberglass to the mast, as with any other portion of a boat, requires proper surface preparation. Working with epoxy and fiberglass is messy and requires a few special tools. Epoxy application should be done indoors or at least out of direct sunlight. The extra effort required to properly fiberglass your mast will be repaid with years of trouble-free service.

Things You'll Need

  • Mast
  • Sandpaper
  • Tack cloth
  • Fiberglass cloth
  • Utility knife
  • Chemical-resistant gloves
  • Respirator with appropriate filter
  • Clean metal container
  • Mixing stick
  • Epoxy resin
  • Squeegee
  • Medium-quality paintbrush
Show More

Instructions

    • 1

      Sand the mast smooth. Best adhesion will be achieved on smooth bare wood. Previously painted or varnished surfaces must be clean and free of chemical contamination. Epoxy will not bond properly over oil, tar or paint thinner.

    • 2

      Use a tack cloth to remove dust from sanding.

    • 3

      Drape the fiberglass cloth lengthwise over the mast. Wrap the cloth around the mast and trim away the excess with a utility knife. Most modern masts will have a channel on the aft section to receive the sail. Trim the fiberglass to reach to the outside lip of the channel on each side. For masts without a channel, cut the edges of the fiberglass so they butt smoothly up against each other. Overlaps are difficult to smooth.

    • 4

      Put on chemical-resistant gloves and respirator before mixing epoxy. Pour the appropriate amounts of resin and catalyst into a clean metal container. Mix slowly and thoroughly with a mixing stick.

    • 5

      Pour a small amount of epoxy onto the mast over the fiberglass. Use a squeegee to spread the epoxy across the surface of the mast. Work the epoxy into the fiberglass as you spread it. Work from the moistened areas toward the dry areas of the mast. When the surface of the entire mast is covered, the fiberglass should be almost invisible against the wood. Allow the epoxy to cure for at least 12 hours before applying the second coat.

    • 6

      Apply a second coat of epoxy with a medium quality brush. Work from the moistened surfaces toward the dry surfaces. After the second coat, the texture of the fiberglass will still be visible on the surface. The fiberglass itself will be clear. Allow the epoxy to cure for at least 12 hours before applying the third coat.

    • 7

      Apply the third coat of epoxy with a medium quality brush. Work from the moistened surface toward the dry surfaces. After the third coat of epoxy, the surface of the mast should be smooth and the fiberglass cloth should be undetectable. Allow the epoxy to cure for at least 12 hours before varnishing.