Fairing epoxy surfaces is a basic skill for epoxy users. Fairing refers to the filling and shaping of low areas so they blend with the surrounding surfaces and appear “fair” to the eye and touch.
The goal of fairing is to create a surface without bumps or hollows. After the major structural assembly has been completed, the final fairing can be easily accomplished with WEST SYSTEM epoxy and low-density fillers.
Fairing Epoxy Surfaces
- Prepare the surface as you would for epoxy bonding. Sand smooth any bumps or ridges on the surface and remove all dust from the area to be faired.
- Wet out porous surfaces with unthickened epoxy.
- Mix resin/hardener and 407 Low-Density or 410 Microlight® filler to a peanut butter consistency. The thicker the mixture, the easier it will be to sand when cured.
- Trowel on the thickened epoxy mixture with a plastic squeegee, working it into all voids and depressions. Smooth the epoxy mixture to the desired shape, leaving the mixture slightly higher than the surrounding area. Remove any excess thickened epoxy before it cures. If the voids you are filling are over ½” deep, apply the epoxy mixture in several applications or use 206 Slow Hardener or 209 Extra Slow Hardener, depending on the ambient temperature. Note: On vertical and overhead surfaces, allow the wet-out epoxy coat to gel before applying the epoxy fairing compound. The fairing compound may sag or slide off the fresh wet-out coat. Apply the fairing compound while the wet-out is still in the gel stage.
- Allow the final thickened epoxy application to cure thoroughly.
- Sand the fairing material to blend with the surrounding contour. Begin with 50-grit sandpaper if you have a lot of fairing material to remove. Use 80-grit paper on the appropriate sanding block when you are close to the final contour. CAUTION! Don’t forget your dust mask. Remove the sanding dust and fill any remaining voids following the same procedure.
- Apply several coats of epoxy resin/hardener to the area with a disposable brush or roller after you are satisfied with the fairness. Allow the final epoxy coat to cure thoroughly before final sanding and finishing.