How to use WEST SYSTEM Epoxy


Fairing structures made with WEST SYSTEM epoxy

After major structural assembly has been completed, final fairing can be accomplished easily with WEST SYSTEM® epoxy and low-density fillers.

Fairing involves filling and shaping low or uneven areas so they blend with the surrounding surfaces and appear ‘fair’ to the eye and touch.

This page covers:

7-step fairing method
Safety warning: avoid inhaling sanding dust
Using WEST SYSTEM 410 Filler for fairing

7-step fairing method

1. Prepare the surface for bonding

Sand smooth any bumps or ridges on the surface and remove all dust from the area to be faired.

2. Wet out porous surfaces with resin/hardener mix

Wet out porous surfaces before applying fairing compound.

3. Mix resin/hardener with a filler

Add 407 Low-Density or 410 Microlight® filler to a resin/hardener mix until it reaches a peanut butter consistency. The thicker the mix, the easier it will be to sand when cured.

4. Trowel the thickened epoxy mix onto the wetted surface

Use a plastic spreader to do this, working it into all voids and depressions. Smooth the epoxy to the desired shape, leaving the mix slightly higher than the surrounding area. Remove any excess thickened epoxy before it cures. If filling voids over 12mm deep, apply the fairing mix in several applications allowing each application to partially cure before proceeding and/or use 206 Slow Hardener® or 209 Extra Slow Hardener™, depending on temperature.

Apply fairing compound to fill all voids and smooth to shape.

When working on vertical and overhead surfaces, remember to allow the wet-out coat to gel before applying the fairing compound which may sag or slide off the fresh wet-out coat. Apply the fairing compound while the wet-out coat is still tacky.

5. Allow the final application of thickened epoxy to cure thoroughly

6. Sand the fairing material to blend with the surrounding contour

Begin with 50-grit sandpaper if it is necessary to remove a lot of fairing material. Use 80-grit paper when close to the final contour.

Sand cured fairing compound to desired contour.

7. Apply two or three coats of resin/hardener mix

When you’re satisfied with the ‘fairness’, apply costs of resin/hardener mix to the area with a disposable brush or roller. Allow the final coat to cure thoroughly before final sanding and finishing.

Safety warning: avoid inhaling sanding dust

Always wear a dust mask when sanding cured epoxy. Remove the sanding dust after you’ve finished to reduce the risk of future inhalation.

Using WEST SYSTEM 410 Filler for fairing

When using 410 Filler, bear in mind that it can be affected by the solvents found in most paints. Surfaces faired with this filler must be sealed with epoxy before applying any solvented paints.