West System 406 Silica Coloidal Additive

406 Colloidal Silica is an epoxy thickening additive used to control the viscosity of the epoxy. It prevents epoxy runoff in vertical and overhead joints. This is a very strong filler. It creates a smooth mixture, ideal for general epoxy bonding and filleting. It is also our most versatile epoxy filler. Often used in combination with other fillers, 406 can be used to improve strength, abrasion resistance, and consistency of epoxy fairing compounds. The result is a tougher, smoother surface.

Making Color-Matched Fillets using 406 Filler:
- To make strong, color-matched fillets, start by thickening a batch of epoxy with 406 Colloidal Silica filler to a mayonnaise consistency. This creates a translucent white/smooth and creamy epoxy. Next, add wood sanding dust until you arrive at the color you need. As a translucent white filler, 406 colors easily when you add wood sanding dust.

- As a result of adding wood dust, you’ll get a colored epoxy that is lighter than the wood. Adding a lot of sanding dust results in a darker color.

- Thickened with 406 filler alone, epoxy has a translucent white look. This nicely offsets the darkening effect of wet wood flour (sanding dust), allowing you to achieve a color that matches the wood tone. To do this well, compare it to the varnished wood surface or epoxy-coated surface you’re trying to match. You can see your goal as you work on matching the thickened epoxy mixture to it.

- It’s important to realize that the epoxy looks like while uncured is what it will look like after it cures. So, if you want a natural wood finish, you can enhance the beauty and elegance of a glued plywood structure with color-matched epoxy fillets.