West Systems Fillers

West System Epoxy Fillers: Precision Additives for Every Repair

WEST SYSTEM has been the trusted name in epoxy technology since 1969, when the Gougeon Brothers pioneered marine-grade epoxy formulations in Bay City, Michigan. At the heart of their system is a philosophy of customization: rather than offering a one-size-fits-all solution, WEST SYSTEM gives builders and repair technicians a purpose-built lineup of fillers designed to modify their core 105 Epoxy Resin for specific jobs — from fairing a hull to bonding structural joints to filling deep voids.

A Filler for Every Application

What sets WEST SYSTEM apart in the fillers category is the depth and specificity of their product range. Each filler is engineered to deliver a distinct combination of viscosity, density, and working properties when blended with the base epoxy system, giving professionals and serious DIYers precise control over the final result.

• 405 Filleting Blend: A strong, wood-toned adhesive filler ideal for creating structural fillets and bonding joints where a natural appearance matters.
• 406 Colloidal Silica: A high-strength thickening additive used to control epoxy viscosity and prevent runoff on vertical and overhead surfaces — one of the most versatile fillers in the lineup.
• 407 Low-Density Filler: A blended microballoon-based fairing filler that produces lightweight, easy-to-sand fairing putties — a go-to for hull and surface fairing work.
• 410 Microlight®: The lowest-density option in the WEST SYSTEM filler family, formulated with multiple particle types to create an extremely lightweight fairing compound that mixes and sands with exceptional ease.
• 403 Microfibers: A fine fiber blend that thickens epoxy into a strong, multi-purpose adhesive particularly suited for bonding wood components.
• 404 High-Density Filler: Designed for maximum-strength bonding where hardware attachment, fasteners, or high-load joints demand the toughest possible bond line.

The Science Behind the System

WEST SYSTEM fillers are designed to work together as a cohesive system. Because different fillers can be combined within the same resin and hardener, builders can blend intermediate characteristics to match unusual applications. This versatility — built around the core 105 System — means a single set of resins and hardeners can be adapted across bonding, fairing, coating, and structural filling tasks without switching product families.

All WEST SYSTEM products are manufactured under ISO 9001:2015 quality standards, reflecting the same engineering rigor that has made the brand the benchmark in boatbuilding, high-performance composites, and marine repair worldwide. Whether you are filling voids in a wooden hull, fairing a fiberglass deck, or reinforcing a composite structure, WEST SYSTEM fillers provide a proven, engineered path to a durable result.