Barrier Coat Additive 16o

422 is a proprietary blend designed to improve cured
epoxy's moisture-exclusion effectiveness. 422 is used as a
barrier coating additive to help prevent gelcoat blistering in
polyester fiberglass boat hulls. 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. One 16 oz.
can of 422 will modify approximately half a gallon of epoxy.