West System 403 Microfiber Additive

WEST SYSTEM 403 Microfiber Additive: The Ultimate High-Strength Thickener for Marine Bonding

Achieve professional-grade structural bonds and flawless repairs on your vessel with WEST SYSTEM 403 Microfiber Additive. As an essential component for any serious boater´s maintenance toolkit, this high-performance thickener is engineered to significantly enhance the strength, reliability, and gap-filling capabilities of your WEST SYSTEM epoxy. Whether you are undertaking a major restoration project, bonding critical structural components, or performing routine repairs, 403 Microfibers provide the confidence and performance that the marine environment demands.

Unmatched Strength for Critical Applications

WEST SYSTEM 403 is a premium blend of cotton cellulose fibers, specifically designed to be used as a thickening additive for bonding applications. When mixed with WEST SYSTEM 105 Resin and a 200-series Hardener, it transforms the epoxy into a robust structural adhesive with exceptional toughness and durability. This thickened mixture is ideal for creating powerful, load-bearing bonds that can withstand the stresses of flexing, vibration, and impact common on any boat. Its superior strength makes it the go-to choice for bonding wood, fiberglass, and other marine materials, ensuring your repairs and constructions last for seasons to come.

Superior Gap-Filling and Substrate Preparation

One of the standout features of this additive is its ability to create a mixture with outstanding physical properties. A microfiber thickened epoxy provides good pre-sizing or impregnation of the substrate and excellent gap-filling properties. This means the epoxy mixture thoroughly "wets out" porous surfaces like wood, penetrating the grain to create a tenacious grip and preventing "epoxy-starved" joints that can lead to failure. For joints that don´t fit perfectly, the 403-thickened epoxy bridges gaps effectively, creating a solid, void-free connection that is often stronger than the surrounding material. The resulting cure is a tough, off-white solid that is also easy to work with and sand, allowing for a smooth, fair finish.

Versatile and Easy to Use

Integrating 403 Microfiber Additive into your workflow is simple and allows for precise control over the viscosity of your epoxy. Depending on the desired consistency for your specific task, you can add from 4% to 16% by weight to a West System epoxy mix. This versatility enables you to create a non-sagging paste perfect for vertical and overhead surfaces, structural fillets, or hardware bonding, ensuring the epoxy stays exactly where you need it. For reliable, permanent repairs and construction that maintain the integrity and value of your boat, trust the proven performance of WEST SYSTEM 403 Microfiber Additive