WEST SYSTEM 404-45 High Density Filler 46oz – Strong Bonding & Gap Filling

Overview

Elevate epoxy projects with WEST SYSTEM 404-45 High Density Filler. This thickening additive is designed to enhance epoxy performance for hardware bonding, gap filling, and the creation of robust structural fillets. When blended with compatible WEST SYSTEM resins and hardeners, it helps you manage workability while pursuing durable, professional results. The cured color is off-white, blending well with many wood tones and epoxy blends.

What it does

The 404-45 high-density filler blends with epoxy systems such as 105 Resin/20X Hardener, G/flex Epoxy 650, or G/5 Five-Minute Adhesive. It increases viscosity to help you control the flow and set of the mix, creating a stable slurry that can stay where placed and form solid fillets or bridges. This makes it a versatile option for a range of bonding and filling tasks.

• Designed for hardware bonding and stud connections to help reduce creep and improve joint stability
• Thickens epoxy to bridge large gaps and form non-slumping adhesive joints
• Compatibility with multiple WEST SYSTEM resin systems for tailored performance
• Color after cure is off-white, aiding visual blending with light woods and epoxies

How to use

Follow practical mixing guidelines to achieve the right viscosity and workability. Blend a small amount of 404-45 filler into your chosen epoxy resin and hardener until you reach a moderately loose slurry that remains in a horizontal gap. Be mindful of air bubbles and avoid overmixing, which can trap air.

• For hardware bonding, mix to a slurry that stays put in a horizontal hole but is not too thick
• Refer to the viscosity guide comparing neat epoxy to the thicker consistencies described as catsup, mayonnaise, and peanut butter

Tips for best results

Use only enough filler to bridge gaps without sagging. A small amount may squeeze out when clamped or when hardware is inserted, indicating a strong contact. Do not fill the mixing cup more than one-third full of epoxy before adding the filler to minimize air entrapment. The amount you add directly controls the mixture’s thickness and flow, so adjust gradually to the task at hand.

Color and curing

When blended with epoxy, the filler helps achieve a predictable off-white cured color, which can be desirable in many projects where a uniform appearance matters.