Wooden Boat Restoration Repair - WEST SYSTEM Epoxy

Figure 6-1 A normal sized pilot hole at the bottom of the oversized
hole provides enough clamping pressure to hold the hardware in position
until the epoxy cures.
Product tip—For
situations where a
high-strength thickened
epoxy is required to be
injected, WEST SYSTEM
Six10 Epoxy Adhesive
is a convenient
alternative to 105
Resin-based Epoxy.
Six10 is a two-part
thickened epoxy that is
mixed as it is dispensed
with a standard caulking
gun. It has a generous
working time of 42 minutes
at 72°F, cures to a
solid in 5–6 hours and
will take high loads in 24
hours.
For more information
about Six10 Adhesive,
see the WEST SYSTEM
User Manual & Product
Guide or visit
www.westsystem.com.
Installing Hardware 44
Figure 6-2 Tighten the fasteners until a small amount of
epoxy squeezes from the joint.
1. Drill an oversized pilot hole to increase the amount of exposed wood area that the
epoxy around the fastener will bond to. This may be much larger than the
fastener—twice the fastener diameter, for example. Drill the hole 2/3 to 3/4 the depth
of the fastener.
2. Drill a normal sized pilot hole at the bottom of the oversized hole to the full length of
the fastener (Figure 6-1). This allows the bottom threads of the fastener to bite into the
wood fiber so the fastener will stay in proper position until the epoxy cures.
3. Prepare the hardware by washing the contact surface of the base with solvent to
remove any contamination. Abrade the contact surface with a wire brush or 50-grit
sandpaper to allow the epoxy to “key” into the surface.
4. Fill the holes to the top with epoxy. Allow the epoxy to soak into the exposed end grain
of the wood for a few minutes. If the hole remains filled after 5 minutes, remove the
epoxy with the syringe.
5. Coat the bottom contact surface of the hardware with unthickened epoxy. Wire brush
or sand the wet epoxy into the surface with 50-grit sandpaper. Sanding the base, coated
with epoxy, will expose the epoxy directly to fresh metal with no chance for the metal
to oxidize.
6. Inject a non-sagging epoxy/404 or 406 mixture (or Six10 Epoxy Adhesive) into the
hole. Use enough mixture so there are no voids in the hole after inserting the fastener.
Coat the bottom of the hardware and the fastener threads with the thickened mixture.
7. Place the hardware in position. Insert and tighten fasteners until a small amount of the
mixture squeezes out of the joint (Figure 6-2). Do not over tighten.
8. Clean the excess epoxy mixture that has squeezed out.
9. Allow the epoxy to cure at least 24 hours before applying load to the hardware. Allow
more time in cool weather.
Bonding the contact surface of a hardware item can contribute a great deal to load
distribution over maximum wood surface area. You can use WEST SYSTEM epoxy to
make good bonds with most metals. However, careful preparation of the metal surface
is necessary for good adhesion. This includes sanding and acid etching. For example,
aluminum requires a two-step surface preparation. The first step involves the use of an
acid conditioner that removes corrosion. The second step chemically stabilizes the
surface and prevents oxidation, allowing time for coating or bonding. The WEST
SYSTEM 860 Aluminum Etch Kit contains complete instructions.
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