The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Chapter 17 – Mold Frames and Permanent Frames 189
Nail heads are placed along
the section line and tapped
into the surface of the floor.
Figure 17-1 <strong>The</strong> nail method for picking up mold sections from the lofting.
frame stock. <strong>The</strong> easy way to do this is to use a pounce
or tracing wheel, but you may also use a pin or a nail.
Connect the pick marks into a line with a batten.
<strong>The</strong> third and most popular method of transferring
lines is the nail method illustrated in Figure 17-1. For
this, you need thick-shanked nails with small, sharpedged
heads. Small box nails work well. Position these
on their sides on the lofting floor, so that the shanks are
at right angles to and the edges of the heads rest on the
station lines. Hold a nail by its point and tap the side of
its shank with a small hammer until the shank is flat in
the floor and close to half of the head is buried. Sink
nail heads in this way at several points along the station
lines, adding more in critical areas such as sharp curves
or chines until you have a good outline of protruding
nail heads. <strong>The</strong>n, place your frame material over the
lofting and gently walk on it to press the nail heads into
the stock. Remove the mold material and use a batten
to connect the nail head impressions into a line.
We have developed a fourth method, shown in Figures
17-2 and 17-3, of marking mold frames. This technique
<strong>The</strong> mold stock is carefully placed on the
positioned nail heads and pressure is applied.
When the mold stock is removed from the
body plan, the nails (or the imprint) should
outline the shape of the section on the stock.
requires making special battens and batten holders,
and therefore takes a little extra time, but it gives fast,
accurate results. <strong>The</strong> holders are screwed or notched
onto long, thin battens which are anchored in place on
the lofting. We can push mold frame material under
this assembly for marking.
You may need more than one batten, especially if
the sharpness of your curves varies considerably from
station to station. Make each one out of a straight,
flexible wood such as ash. Batten thickness depends
on the degree of curvature of your station lines: each
batten should flex comfortably along the lines on which
it will be used.
Next, cut eight or so pieces of wood to approximately
11 ⁄2" � 1" � 18" (38mm � 25mm � 450mm). <strong>The</strong>se
are your batten holders. Drill one or two holes for nails
at one end of each piece. You can use any long, thin
nails you have on hand as long as they slip through
these holes easily with no slop, so be sure that your drill
is the same size as the shank diameter of your nails. Cut
a thin wedge out of the bottom of each stick, beginning