West System 406 Colloidal Silica Adhesive Filler

When maximum bond strength and precise epoxy control are essential, WEST SYSTEM 406 Colloidal Silica is the professional choice. This premium silica-based additive thickens mixed epoxy resin to create a smooth, non-sagging adhesive that remains exactly where it is applied—even on vertical and overhead surfaces.

Trusted by boat builders, yacht maintenance professionals, woodworkers, and composite manufacturers worldwide, 406 Colloidal Silica transforms standard epoxy into a high-strength structural adhesive suitable for demanding repairs, laminating, and construction projects.

Whether you’re laminating fiberglass, bonding timber, creating structural fillets, reinforcing composite parts, or filling gaps between components, this versatile additive delivers exceptional mechanical strength, excellent wear resistance, and long-term durability.

Unlike lightweight fairing fillers that are designed for easy sanding, WEST SYSTEM 406 is specifically formulated to maximize the structural performance of cured epoxy. It can also be blended with other WEST SYSTEM fillers to fine-tune viscosity and handling characteristics while maintaining outstanding bond strength.

Available in 275g and 1.5kg containers, you can choose the package size that best suits your project—whether for occasional repairs, routine maintenance, or large-scale production and professional applications.

Key Features

• Premium silica-based epoxy thickening additive
• Produces a smooth, non-sagging epoxy mixture
• Prevents resin runoff on vertical and overhead surfaces
• Creates extremely strong structural adhesive bonds
• Excellent for bonding, filleting, and gap filling
• Increases abrasion resistance and durability
• Can be blended with other WEST SYSTEM fillers
• Suitable for structural marine and industrial applications
• Compatible with WEST SYSTEM 105 Epoxy Resin and all WEST SYSTEM hardeners
• Also compatible with G/flex® 650 Epoxy and G/5® Five-Minute Adhesive

Available Variations

275g

Perfect for DIY users, regular maintenance, boat repairs, woodworking projects, and medium-sized epoxy applications. Easy to store and ideal for workshops requiring smaller quantities.

1.5kg

Designed for professional boatyards, composite workshops, manufacturers, and users with high epoxy consumption. An economical solution for large projects and continuous production work.

Ideal Applications

• Yacht and boat construction
• Marine structural repairs
• Fiberglass repairs
• Wooden boat building and restoration
• Composite manufacturing
• Carbon fiber construction
• Structural bonding
• Fillet creation
• Gap filling
• Vertical and overhead epoxy applications
• High-strength adhesive joints
• Industrial epoxy assemblies

Why Choose WEST SYSTEM 406 Colloidal Silica?

Selecting the correct epoxy filler is essential for achieving reliable, professional-quality results. WEST SYSTEM 406 Colloidal Silica allows you to precisely adjust epoxy viscosity without compromising strength, making it one of the most versatile structural fillers in the WEST SYSTEM range.

Its moisture resistance, exceptional bonding performance, and non-sagging consistency make it particularly valuable in marine environments where durability and structural integrity are critical.

Whether you’re repairing a fiberglass hull, bonding teak components, reinforcing composite laminates, assembling wooden structures, or carrying out professional yacht maintenance, WEST SYSTEM 406 delivers cleaner applications, stronger adhesive joints, and long-lasting performance.

Technical Specifications