Final Fairing & Finishing - WEST SYSTEM Epoxy

ple, and one of the frames is 5 16" too high, you would have to alter the shape of the hull
to avoid sanding a hole through 1 4" planking.
If you are fairing a hard surface like a fiberglass, aluminum or steel hull, or a lead keel,
removing a lot of material is impractical. You are pretty much limited to filling the low
areas and establishing the level near or above the highest point on the surface, (option
2). Many steel and aluminum boats are built this way. A layer of fairing compound is
applied over the completed hull and all of the fairing takes place in the easy-to-sand
fairing compound outside of the hull’s metal surface.
Removing high areas
The first task in overall fairing is locating the high and low areas. Developing a good
eye or feel for finding high or low areas may come naturally or with practice and trial
and error. Whether you develop a good eye or not, a batten or chalk stick is an indispensable
fairing tool. See Appendix A, page 23. A batten will also help you develop your
eye by providing an accurate backup measurement to check against your eye and hand
measurements.
As you hold the batten firmly against the surface, it will rest on the high spots and
bridge the low areas. By moving the batten to different positions in an area, you should
be able to get an idea of the surface topography.
Gaps under batten at low areas
Chalk rubs off on high areas
Figure 2 A batten will reveal the high and low areas, and the difference
between them. Chalk applied to the batten will rub off on the high spots.
Final Fairing 3
Mark the high spots by applying carpenters chalk to the face of a batten, and rubbing
the batten over the surface. The chalk will be deposited on the high spots (Figure 2).As
you take the high spots down to fair, you can use the chalk stick as often as you like to
monitor your progress. Continue removing high spots until you are satisfied with the
fairness.
Methods for removing high spots depend on the material and how much of it needs to
be removed. For aluminum, steel, fiberglass or other hard materials, a heavy duty disc
sander may be the most practical tool to use. For rough fairing on wood or cured fairing
compound, a plane, disc sander, belt sander or air file can be used, but some skill
and experience are required to avoid sanding too deep. The short contact area of these
tools also increases the risk of removing material from the wrong areas.
Warning! The dust generated from fairing can make it the dirtiest and one of the most hazardous
operations in the boat shop. An appropriate dust mask and eye protection should
always be worn. Wear appropriate protective clothing and keep your work area well ventilated.
Refer to the safety information in the WEST SYSTEM User Manual & Product Catalog
and on all product labels. Read and follow all power tool safety information.