I have used a variety of casting materials for creating gila monster replicas. However, my favorite is the Polytec 1512 casting resin. The beadlike osteoderms on the Gila monster’s skin is somewhat problematic in that they tend to produce small air pockets during the casting process. I prefer 1512 because it has the slowest curing time which provides ample time to spread the resin thoroughly into the mold’s detail. Also, the 1500 series resins are very weather resistant, strong and do not become brittle over time. Pigments are also available to darken the resin during the mixing process.