How to Make a Kayak Mold From a Wood Stripper

To easily make multiple fiberglass copies of a kayak, you must construct a fiberglass mold. To build a mold, you build a plug, which is an exact copy of the boat you want to mold. You use a wood stripper, refine its shape, coat it with a release agent and then cover the kayak with a gel coat and fiberglass. When the fiberglass cures, the mold forms. If you already have a wood kayak, you do not need to build the plug, which makes the process quicker.

Things You'll Need

  • Automotive putty
  • Sandpaper, 80-grit, 120-grit, 220-grit, 400-grit, 600-grit
  • Spray gun for paint
  • Fast-build automotive primer-surfacer
  • Buffer
  • Heavy-duty cleaner for machine polishing molds
  • Sealer glaze for finishing molds
  • Basic mold wax
  • Soft cotton cloth
  • Hot glue
  • Hot glue gun
  • Minicel foam
  • PVC tape
  • PVA mold release
  • Tooling gelcoat
  • MEKP
  • 3-oz. fiberglass mat
  • 4-oz. fiberglass cloth
  • Vinylester resin
  • Paintbrush
  • Bolts
  • Water
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Instructions

    • 1

      Use putty and sandpaper to refine the wood stripper's shape until the shape looks correct. Remove or fill any defects. Finish sanding with 220-grit sandpaper to make the surface smooth. Any imperfection in the wood stripper transfers to the mold and then to the fiberglass boat.

    • 2

      Spray the surface with a fast-build automotive primer-surfacer. Use a spray gun for paint for this and several other procedures during the mold-making process. After it dries, wet sand the surface progressively with 220-grit to 600-grit sandpaper.

    • 3

      Buff the plug with a heavy-duty cleaner for machine polishing molds. Let the cleaner solvents evaporate overnight. Follow the cleaner buffing with a buffing of sealer glaze, which provides a surface for the paste wax.

    • 4

      Hand-buff with a cotton cloth five coats of basic mold wax onto the wood stripper. Buff the mold like you would when putting wax on a car. Buff until the surface appears shiny. Wait five hours for the wax to dry.

    • 5

      Build a flange around the wood stripper's seam, the point where the hull and the deck joins, by hot gluing minicel foam to the hull below and even with the seam. Cover the foam with a PVC tape.

    • 6

      Spray the wood stripper's deck with two coats of PVA mold release in a room with a controlled 70 degree Fahrenheit or greater temperature. Let dry for a half-hour.

    • 7

      Spray on a coat of 0.5mm thick gel coat catalyzed with MEKP according to the manufacturer's instructions. Non-uniformly applied gel coat wrinkles when applying a second coat. After the gel coat dries, apply a second coat.

    • 8

      Reinforce the corner of the flange with fiberglass mat.

    • 9

      Lay a layer of fiberglass cloth over the wood stripper. Mix up two cups of vinylester resin catalyzed with MEKP according to the manufacturer's instructions. Carefully apply the resin to the fiberglass with a paintbrush. Mix up more resin as needed. Use enough resin to completely saturate the fiberglass cloth; it's saturated when it turns from white to clear. Let it cure overnight.

    • 10

      Lay two layers of 3-oz fiberglass mat over the cloth and saturate it with vinylester resin. Add an extra layer of mat over the flange and flange corner. Let it cure overnight between layers. Add reinforcements to any large flat areas that might deform.

    • 11

      Flip the wood stripper and follow the same process for the other side. Bolt both sides together and set it somewhere warm for two works to completely cure.

    • 12

      Pull both halves of the mold from the wood stripper and wash out the wax and PVA with water.

    • 13

      Sand the mold with wet sandpaper working progressively from 200-grit to 600-grit until your remove any imperfections.

    • 14

      Prep the mold's surface with heavy-duty cleaner, sealer glaze, mold wax and PVA following the same procedures used for prepping the plug. After the prep, you can layup your first fiberglass kayak.