The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

240 Hull Construction Methods
Voids may be caused by too little staple pressure, by
insufficient quantities of adhesive, and by non-uniform
epoxy application. Check the removed veneer for staple
holes in and around the void. It may be obvious that
there were too few staples, and therefore not enough
pressure, in that area. Significant numbers and areas of
voids indicate a general lack of adhesive. If you see no
voids at all, but excessive quantities of epoxy exude
from around the edges of the veneer, you are probably
applying too much. Reduce the amount on the next try
and keep experimenting until you gain sufficient
experience.
Applying the Second Layer of Veneer
<strong>The</strong> laminating process really begins with the second
layer of veneer. Start this layer as you did the first by
positioning a master veneer in the middle of the mold.
This veneer usually runs at the same angle as the first
layer, but in the opposite direction so as to form a
balanced double diagonal.
When you have decided its position, use a pencil to
carefully outline the new master veneer on the first
layer and then remove the piece. Pull out all first layer
staples within the marked area and release it from the
mold. First layer veneers are roughly perpendicular to
second layer veneers, so this staple pulling does not
usually disturb their positioning. Staples on either side
of the marked area will continue to hold the first layer
in place.
When you are ready to attach the second-layer master
veneer, apply adhesive to both the outlined surface on
the first layer and the underside of the new master
veneer. Put the piece in its marked position and hold it
with your hand while you insert several locating staples
at both outer edges, about midpoint along the plank.
<strong>The</strong>se staples keep the veneer from moving and help to
free both hands for stapling. Use an adequate stapling
pattern for your situation and laminate the master
veneer. Remove any epoxy that squeezes out at the
edges so that uncured epoxy won’t interfere with your
next task.
Spile a neighboring veneer just as you did on the first
layer, but do not bond it to the mold. We recommend
that you wait to apply adhesive to second layer veneers
Figure 21-18 Installing a second layer of planking.
until you have spiled and fitted the entire layer. When
they are trimmed, temporarily position pieces with a
few staples (it’s not necessary that they be held snug
against the mold as long as they lie flat and their adjacent
edges fit) until you have covered the entire hull surface.
<strong>The</strong>n go back to the veneers on either side of the master
veneer and begin laminating.
To do this, remove a piece or two at a time, apply sufficient
epoxy mixture to all bonding surfaces, and staple
the new veneer in place. Proceed down the hull until
you have bonded the entire layer. While there is a
disadvantage to this method in that you have to tack
the wood to the mold twice, the real efficiency comes
from being able to laminate all the veneers at one time.
This uses both epoxy/filler and labor economically and
avoids much of the mess that results from simultaneous
spiling and bonding operations.
You can remove staples from second layer veneers
before you have installed the entire layer. Try to pull
staples out before the epoxy has fully cured. We find
that it works best to apply veneers one day and pull
the staples the next, but you can begin as soon as 7
or 8 hours after application.
If you find areas where the two layers relax slightly
from the mold as you pull out the fasteners, restaple
them tightly with as few permanent, non-rusting
staples as possible. This springback is a problem only
on hulls with unusual shapes and curves, and its only
significance is that the staples may make the hull a
little more difficult to remove from the mold. We’ve
never had much trouble with this in our hulls, but we