Wooden Boat Restoration Repair - WEST SYSTEM Epoxy

3.1.1 Filling with epoxy
3.1.2 Filling with wood
Repairing Localized Dry Rot 14
Small cavities are most conveniently filled with solid thickened epoxy as follows:
1. Prepare the surface (Section 8.4.1). Be sure the area is thoroughly dry.
2. Wet out the repair area with the resin/hardener mixture (see Two-step bonding, page
65).
3. Fill the cavity with epoxy thickened with a high-density (406,404 or 403) filler to a
peanut butter consistency. Trowel the mixture into the void with a plastic spreader or
mixing stick (Figure 3-2). Smooth the mixture flush with the surface and remove any
excess before the mixture begins to cure.
4. Allow the mixture to cure thoroughly before sanding.
Figure 3-2 Trowel thickened epoxy into smaller voids. Figure 3-3 Bond a dutchman into larger cavities. Bevel the sides
of the cavity and the dutchman to match.
Dutchman—A
small piece of wood
shaped to closely fill the
void in a larger piece of
wood.
Larger cavities should be filled with wood wherever possible. This method restores the
original strength of the wood. The procedure involves carving a dutchman to the shape
of the void and bonding it in place with epoxy as follows:
1. Prepare the dutchman. Use the same kind of wood if possible. Carve the cavity to a
geometric shape if necessary to make shaping the plug easier. Bevel the sides of the
cavity. The longer the bevel on the sides running across the grain, the stronger the
repair (Figure 3-3). An 8-to-1 bevel (8" long for every 1" deep) or greater will be close to
the original strength of the wood. Check the dutchman for fit. Thickened epoxy will
fill a fairly large gap, so the fit doesn’t have to be perfect. Prepare the surfaces for
bonding (Section 8.4.1).
2. Wet out the bonding surfaces of the cavity and the plug with resin/hardener mixture.
3. Apply thickened epoxy/adhesive filler (406, 404 or 403) (mayonnaise consistency) to
the cavity surfaces. Using the mixing stick, apply enough of the thickened mixture to
fill any gaps.
4. Insert the plug into position. Thickened epoxy should squeeze out of the joint.
5. Clamp the plug into position. Weights or staples may be used to hold the plug until the
epoxy cures. Remove excess epoxy before it begins to cure.
6. Allow to cure thoroughly before removing clamps or sanding.
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