4:1 polyester primer catalyst is a patented, epoxy enriched catalyst that provides unsurpassed performance when mixed with EVERCOAT’s line of 4:1 polyester primer surfacers. It provides end users with an easier mix ratio than conventional polyester primers and provides a more uniform mix. Fast 4:1 polyester primer catalyst is a patented, epoxy enriched catalyst that provides unsurpassed performance in cooler temperatures, when mixed with EVERCOAT’s line of 4:1 polyester primer surfacers.