The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Chapter 7 – Estimating Materials and Labor 53
Hull Surface Price/ Price/ No. Price
Material Area Sq Ft Layer Layers Materials
1 ⁄8-Inch sliced cedar veneer 300 Sq Feet X .44 = 132 00 X 4 = $528 00
Figure 7-2 Sample detailed veneer estimate.
item by item. Be prepared to find that your local lumberyard
does not carry exactly what you need. Use your
best judgment in deciding what base stock sizes are
most suitable to your applications. Try to work out the
most economical uses of materials, especially plywood,
but allow generous margins for waste. Some areas are
particularly difficult, so pay extra attention to them.
Few lumber dealers will be able to sell you a perfect
21 ⁄2" � 11 ⁄2" board, 25' long, for a sheer clamp. You may
choose, therefore, to buy two 1" � 6" boards, each
25' long, and laminate it from them. This will require
more lumber than you really need and result in some
waste. If you can’t find any 25' boards and decide to
scarf up shorter ones, order at least an extra few feet
of wood for the joint.
You may plan to use many layers of wood to laminate the
stem. <strong>The</strong> layers must be sawn from stock of adequate
size, but before actually bending them to your curves,
you won’t know the best thickness of each layer. As a
result, you won’t really know how much stock to buy.
Take an educated guess, remembering that a saw blade
removes about 1 ⁄8" (3mm) of wood with each cut. If
you will be using 1 ⁄8" (3mm) layers, you’ll have a 50%
waste factor. If you can bend 1 ⁄4" (6mm) laminating
stock, waste will be noticeably reduced.
Before lofting them, it’s very hard to know how many
frames can be cut from a sheet of plywood. Given the
Sub Total Veneer $528 00
+20% Waste $105 60
Total Veneer Cost $633 60
price of plywood, you don’t want to buy too much more
than you will need. To work around this difficulty, use
your imagination—and scraps of paper if necessary—to
come up with the most efficient use of material. Order a
little extra to be on the safe side.
Because of the unusually high waste rate in frame
construction, the costs of interior items are sometimes
difficult to predict. Lumber requirements are usually
not very critical, since you probably will have plenty
of short ends and scrap for cleats and framework.
Wood trim sizes and quantities are often indicated in
plans. Plywood, however, can pose some problems.
Look over your plans to identify which interior components
will be built with one or more sheets of plywood.
If, say, you plan six 30" � 6' bunks and use a sheet for
each, you’ll have six leftover pieces which are not
particularly useful for anything else. Think of areas
where they might fit and consider scarfing them into
a larger piece. Ask yourself if any rounded partitions,
bulkheads, shelves, or bunks can be cut out of rectangular
stock. When you’ve finished this process, count
up the number of full sheets you’ll need.
All wood surfaces on your boat should be coated with
WEST SYSTEM epoxy. Plan to apply at least two
coatings—one initial saturation coat and one buildup
coat—to interiors and several more buildup coats to
exterior surfaces. Epoxy will be used as an adhesive
Application Coverage ft2 /lb Coverage m2 /kg Waste Rate
Initial saturation coat 35 ft2 /lb 7.1 m2 /kg 20%
Secondary buildup coat 40 ft 2 /lb 8.2 m 2 /kg 20%
Interlaminate glue joint 13 ft 2 /lb 2.7 m 2 /kg 20%
Fiberglass saturation coat 12 oz/42 2 (400 g/m 2 ) 12 ft 2 /lb 2.5 m 2 /kg 10%
Figure 7-3 Estimating WEST SYSTEM epoxy. A 105/205 or 206 Group B weighs 11 pounds. A 105/205 or 206 Group C weighs 50
pounds. Refer to the current WEST SYSTEM price list to calculate the cost per pound and per square foot. Contact the <strong>Gougeon</strong>
technical staff to estimate alternate hardeners and sizes.