WEST SYSTEM 422 Barrier Coat Additive 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. 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 weight-3 tablespoons per 8 fl. oz. epoxy (approximately 32 oz. per B group).
December 28, 2018
I discovered this product accidentally in the West Marine store. I had already bought three quarts of Interlux interprotect that we're recommended by the technical advisor. The West System barrier additive s easy to mix up and I thought safer than a solvent based product although I wore my respirator since the mica makes a very fine particulate mist when you are mixing it in. I also mixed in white pigment which should help with the final finish. It is thick and covers well and is self- leveling and I was really impressed with the results.
July 24, 2008
I needed to protect a few small areas of fiberglass on the inside of an old dinghy that had been degraded from years of sun exposure. This product seemed like a cost effective solution since I already had the epoxy.