The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Chapter 25 – Compounded Plywood Construction 299
width of the keel joint, the width of the glass tape influences
the shape of the folded hull. Wider glass cloth
adds stiffness to the plywood, and this keeps it from
bending as much as it would if it were not covered with
glass. As a result, the hull is fuller along the keel line
and more compounding is demanded of the panels.
<strong>The</strong>re are at least two ways to apply the fiberglass tape.
You can install it dry, pressing it into the partially cured
keel and then wetting it out with a stiff brush and
unthickened epoxy, but this can be a lengthy operation
because of the awkward working posture. Since it’s
difficult to maneuver a squeegee from this angle, the
dry method may also result in a little extra weight, and
you might want to avoid this on a small boat. It’s much
more convenient to wet out a measured length of glass
tape on a board which has been wrapped in plastic,
remove excess epoxy with a plastic spreader, and then
roll up the tape. Transfer it to the keel, unroll it in
position, and smooth it out. Applying glass tape in the
bow and other confined areas can be troublesome, so
use the wet method in these spots.
To apply fiberglass cloth to the keel joint of a large boat,
you may have to work out a slightly different procedure.
A hull is very fragile until the keel has cured, so
you can’t get inside it to lay the tape. Instead, rig up a
scaffold on which you can stand. Run a stick that is at
least a foot longer than the widest point of the hull
Figure 25-10 Applying glass tape over a keel fillet on a 30'
(9.1m) hull.
Brush fastened to stick to
wet out fiberglass tape
Support
notched to
proper keel
angle
Alternate tape holder
Figure 25-11 Applying fiberglass tape to the composite keel
of a large hull.
through the center of a roll of glass tape and rest its
ends on the sheers. If the hole in the center of the tape
is too small for the stick, form a wire coat hanger into a
U-shaped holder, bending the ends of the wire into
hooks so it can hang from the stick. Find a second
stick—this one should reach the keel easily from the
outside of the boat—and fasten a brush to it. We use
the stiff, 2" (50mm) wide brushes that are sold for
cleaning automobile parts. Roll dry fiberglass tape onto
the keel line and use the long brush to wet it out
completely with epoxy.
No matter how you apply the fiberglass, closely watch
the guidelines up from the keel as you work. Position
the tape evenly on the panels because it will affect stiffness.
If you are applying several layers of cloth, arrange
them in an overlapping pattern so that their edges will
be feathered. If you are using various tape widths, lay
the widest first. Carefully control the epoxy since it too
increases stiffness. Again, use the marks as guides, and
keep the epoxy lines equally spaced from the center of
the keel.
Folding Up
When the keel and glass tape have fully cured, the
plywood will be folded into the shape of the hull. A