• THICKENING ADDITIVE: West System 406 Colloidal Silica is a fumed silica filler designed to thicken epoxy resin for a variety of applications.
• VERSATILE USE: Ideal for bonding, filleting, and fairing on wood, fiberglass, and metal surfaces where a strong, gap-filling mixture is needed.
• MADE IN THE USA: Manufactured domestically to ensure consistent quality and reliable performance in every application.
• EASY TO MIX: Blends smoothly into West System epoxy resin and hardener to achieve the desired consistency, from a light thickening to a non-sagging paste.
• STRONG BONDS: Creates high-strength, durable fillets and bonds that resist cracking and hold up well under stress and load.

WEST SYSTEM 406 Colloidal Silica is a versatile epoxy filler and thickening additive designed to modify the consistency of epoxy resin systems for a wide range of applications. Made in the USA, this fine-particle silica additive blends smoothly into epoxy mixtures to create gap-filling pastes, fairing compounds, and strong adhesive bonds. It is ideal for use in boat building, woodworking, and general repair projects where a thickened, non-sagging epoxy mixture is required. The 406 Colloidal Silica produces a thixotropic mixture that resists running or sagging on vertical surfaces, making it especially useful for overhead and angled applications. It mixes easily and uniformly, giving you precise control over the final consistency of your epoxy blend. Whether you are filling voids, bonding surfaces, or creating structural fillets, this additive delivers reliable, consistent results. Suitable for both professional craftsmen and dedicated hobbyists, WEST SYSTEM 406 Colloidal Silica is a trusted solution for achieving high-strength, durable epoxy applications.