Final Fairing & Finishing - WEST SYSTEM Epoxy

Release fabric Guide
Figure 11 Push the batten into the ridge. Apply
pressure only where the batten touched the high
spot you marked earlier.
7. Remove the release fabric strips and mark the center of the batten impression with a
permanent felt marker to act as a sanding indicator. Sand the ridges on either side of
the batten impression flush with the center. Avoid sanding into the profile. You should
be left with smooth bands of fairing compound that will be used as guides to accurately
apply the remaining fairing material.
8. Wet out the surface between the guides with epoxy. Allow the coating to gel.
9. Apply a layer of the epoxy/407 or 410 filler to the surfaces between the profile guides.
Use the same filler and filler consistency that was used to make the guides. Use a plastic
spreader to apply and smooth the mixture slightly higher than the guides.
10. Shape the fairing mixture before it begins to gel, using an appropriate batten. With the
batten held perpendicular to and pressed to the guides, drag it along the guides. The
batten will follow the guide profiles, removing excess mixture and leaving the surface
between the guides smooth and level with the guides (Figure 12). To give yourself adequate
working time in warmer temperatures, use 206 or 209 Hardener or fill just one
section at a time. Allow the fairing mixture to cure thoroughly.
11. Sand the cured surface fair, being careful not to sand through the indicator you marked
on the top of the guide. Use battens to check for fairness in both directions. Fill any remaining
low areas again when cured. Repeat as necessary until you are satisfied with
the shape and fairness of the surface.
12. Repeat the process on all areas to be faired. When you are satisfied with the fairness
and smoothness, apply epoxy barrier coats and finish as described in the Finishing
section.
A variation of the previous method is to apply fairing compound to a large area. Lay
strips of release fabric on the surface in several locations, and then press a batten to the
surface at each location before the mixture begins to gel. If a thick enough layer of fairing
compound is applied, the batten will leave a fair profile indentation in the fresh
mixture. When the mixture cures, remove the strips and use the batten profiles as sanding
guides. This method reduces the number of steps in the procedure, but requires
more sanding.
Template guide method
Final Fairing 9
Figure 12 Drag the batten along the guides,
removing excess mixture and leaving the surface
between the guides smooth and level with the
This method is similar to the batten guide method except that a template describing a
specific profile is used to shape the guide rather than a batten. Although a batten-generated
profile may be fair, the high points of the unfair surface will determine the profile.
Template profiles may be lofted from offsets (See Appendix B) or transferred from
an existing surface (See Template Transfer following this section).