The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

242 Hull Construction Methods
edge of a permanently positioned veneer. This veneer
acts as a guide on which the tool rides. It’s important,
of course, that the machine cut exactly 1 ⁄8" deep, so it
will not cut into the veneer under it. <strong>The</strong>re can be no
gaps between veneers wider than the 2" the tool can
cut. Since typical planks are about 3 ⁄4" (18mm) apart
at the ends and 13 ⁄4" (45mm) apart at the middle, this is
not a serious limitation. Whichever tool you use, make
sure that it is sharp. Otherwise, the blade will tend to
follow the grain of the veneers, which, when it runs in
the wrong direction, will pull the saw guide away from
the true veneer edge.
When we laminate our veneers with a mechanical spiler,
we’re careful not to shoot any staples in the area where
the machine will cut. We cut one veneer with the spiler,
using the opposing veneer as a guide. <strong>The</strong> tapered space
between the pieces thus becomes a swath exactly 2"
wide. We remove the wood that has been cut away and
then carefully clean any sawdust and contaminated
adhesive from the gap and apply fresh adhesive. Next,
we fit a 2" wide filler veneer, filling up the gap between
the two veneers. This procedure is repeated over and
over for each space between veneers over the entire hull.
We usually have one team that applies only veneers and
moves down the hull quite rapidly, carefully setting
each veneer so that a minimum amount of waste is
generated in the spiling process. <strong>The</strong>se workers scribe
the filler spacing and make a point of stapling outside
the area of veneer that will be removed. <strong>The</strong> spiling
team follows, sawing 2" gaps and immediately
laminating 2" veneer strips in the slots they cut. Fitting
and laminating in a single operation is very fast and
makes the laminated hull more economically feasible
from the standpoint of man hours required.
We should point out that cutting and removing veneer
to make the 2" gap must be done before the epoxy in
the lamination has cured. When the adhesive is allowed
to set too long, it’s very difficult and time consuming to
remove excess veneer and epoxy to prepare the opening
for the filler veneer.
Figure 21-20 shows a simple spiling tool made from
a small hand drill. A 10" long, 1 ⁄2" wide by 1 ⁄8" thick
(250mm � 12mm � 3mm) piece of steel forms a
Plywood
base
plate
Base
Drill motor chocked
and secured
Saw set flush with
bottom of guide
Shaft
1 ⁄8" Flexible guide
Drill motor
Figure 21-20 Mechanical spiling tools.
Blade
Nuts
Router jig for
spiling/cutting
guide. We bend this until it conforms to the hull’s more
severe curves and follows a veneer edge. We then make
our own small circular 2" diameter saw blade from the
steel blade of an old hand saw, bolt this blade between
two nuts on a 3 ⁄8" (9mm) diameter shaft of threaded
rod, and chuck it in the drill. Finally, we bond a piece
of wood to the top of the drill as close to the front and
the chuck as possible to control the cutting depth of
the saw blade.
A tool that is easier to adapt but a little bulkier and
heavier was the small 41 ⁄2" (115mm) diameter panel
saw. With this, just bolt a simple guide on the base and
set the saw depth for 1 ⁄8" (3mm). <strong>The</strong> modified panel
saw works very well in most situations, but it is a little
cumbersome to operate when cutting veneers on bigger
boats.
You can also use a router for mechanical spiling, as
shown in Figure 21-20. A router cut has a major
advantage in that it is not influenced by the grain of
the wood and can therefore be more accurate. Its
disadvantage is that it makes a good deal of wood
debris and this contaminates the area between the two
veneers and requires more cleanup before the filler
veneer can be installed. Router bits also wear out faster
than saw blades. In spite of these shortcomings, some
builders prefer router mechanical spilers because of
their accuracy.