The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Chapter 17 – Mold Frames and Permanent Frames 197
methods. In conventional construction, where paint
and varnish are used to coat surfaces and something
else is used as an adhesive, the various substances may
be incompatible. When you use wood/epoxy construction
techniques, however, with WEST SYSTEM epoxy as
both a coating and an adhesive, the problems of incompatibility
never arise. If you precoat a bulkhead or rib
with epoxy and then use the same epoxy to bond that
piece in the hull, it will form a homogeneous encapsulation
and joint. It does not matter that the epoxy
coating on the surface has cured at a different time than
the bonding adhesive, as long as you do a good surface
preparation.
Precoating saves time and it also protects pieces from
minor nicks and gouges. Cured WEST SYSTEM epoxy
is very hard. It will resist a certain amount of errant
hammering and banging of jigging lumber. <strong>The</strong> coating
is not indestructible, however. It can be damaged, so try
to avoid hitting it.
If you have put a precoated bulkhead in the set-up and
adhesive squeezes out and runs down onto it as you
plank the hull, wipe off the excess epoxy, smooth it out,
or form it into a fillet before it cures. A beaded run
down the bulkhead will be unsightly, so wipe it up
before it sets. If a drip does cure, it isn’t a disaster; you
will just have a little extra sanding to do later, or you
can use a sharp cabinet scraper to remove the drip.
Figure 17-9 Prefinishing permanent frames for a 60' (18m)
trimaran.
Figure 17-10 Permanent frames ready for set-up. <strong>The</strong>se
frames have legs and spalls attached. <strong>The</strong>y have been
prefinished and notched for stringers.