West System 655-42216 Barrier Coat Additive

West System 655-42216 Barrier Coat Additive

Protect your hull from the inside out. The West System Barrier Coat Additive is a proprietary blend mixed directly into epoxy resin and hardener to significantly improve the cured epoxy’s ability to resist moisture penetration one of the leading causes of gelcoat blistering on fibreglass boats.

When added to a mixed epoxy system such as West System C105A Epoxy Resin, this additive transforms standard epoxy into a high-performance barrier coating. It also increases the abrasion resistance of the cured film, making it well-suited for below-the-waterline applications where the hull faces constant exposure to water and mechanical wear.

Key Features

• Improves moisture-exclusion effectiveness of cured epoxy
• Helps prevent gelcoat blistering on fibreglass hulls
• Increases abrasion resistance of the cured epoxy film
• Mixes directly into the epoxy system no separate application step
• Ideal for below-the-waterline barrier coat systems

Parts Desk Insights

Best Use Case: Recommend this additive to customers who are repairing or re-coating a fibreglass hull, particularly those dealing with existing osmotic blistering or wanting to prevent it on a new or stripped hull. It’s most effective when applied as part of a multi-coat barrier coat system over bare fibreglass, before antifouling paint. Pair with the appropriate West System C105A Epoxy Resin and a compatible hardener such as the West System C205 Hardener or West System C209SA Extra Slow Hardener. Remind customers to follow the full surface prep and application sequence for best results the additive enhances the system but does not replace proper prep work.