Poly 15-3X is a 1:1 mix, filled polyurethane liquid casting plastic that has a 5 minute working time and a ~1 hour demold time. The filler in Poly 15-3X gives it a dense stone-like feel making it ideal for backfilling cold cast bronze parts. The filler also makes 15-3X a very economical, low-cost resin.
Watch Poly 15-3X being used to make a low-cost cold cast bronze (Part 1)
Watch Poly 15-3X being used to make a low-cost cold cast bronze (Part 2 - Finishing)