West Systems Barrier Coat Additive 422
422 Barrier Coat Additive Add to mixed resin/hardener at the rate of 5%-10% by volume or 1.5 tablespoons per 8 fl oz of epoxy (10 strokes each of resin and hardener from 300 Mini Pumps). 36 oz of 420 will modify up to five gallons of mixed epoxy.
While WEST SYSTEM Epoxy creates an excellent moisture barrier by itself, 422 Barrier Coat Additive is a proprietary blend designed to further improve cured epoxy’s moisture exclusion effectiveness. 422 is used as a barrier coating additive to help prevent gelcoat blistering in polyester fiberglass boats. 422 also increases the epoxy’s abrasion resistance. Cures to a light gray color.
Add to mixed resin/hardener at the rate of 15 to 20% by volume or 3 tablespoons per 8 fl oz of epoxy. 16 oz can of 422 will modify approximately half a gallon of mixed epoxy.