The resin we used to cast the hands in is a two part casting resin, we used Instacast from Douglas and Sturgess. If you used a stone hand to bake these in, then you have a very real possibility (I almost want to say 100%, but there may be someone out there who got lucky) that the fingers will snap when you take the glove off, or even sooner, when you make the fiberglass mold of the glove sculpture. If you’ve forgotten, the reason we need these for gloves is so that when we take the glove off of the arm after we’ve cast it in foam latex, the glove won’t tear with you taking it off, since the fingers will come off and you can then take the fingers out. You can color polyurethane before casting using our Circius Polyurethane Dyes.Now that you’ve made a mold of the stone hands (and if you’re having issues getting the stone out of the fiberglass mold, because we did, then we ended up having to chisel it out, and shatter and break the stone out of the hand) you can finally cast some arms with fingers that come out. It will not cure well in humid climates or in molds that contain water. Our polyurethane resins are also the perfect choice for cold casting when combined with our metal, stone and wood powders to create beautiful cold castings that exhibit the realistic look of rich metals, stone and wood.Īs a caution, polyurethane is very moisture sensitive. Polyurethane Casting Resins for Cold Casting The advantage of polyurethane resins over polyester resins is that these formulas are very low in odor compared to carcinogenic producing smells of polyester resins. Therefore, the use of a pressure pot is recommended to perfect the casting without bubbles. However, no water clear polyurethane casting resin is completely bubble free. We even offer a unique polyesher resin formula that will expand (point up) your castings up to 160% The advanced formula clear resins set with fewer air bubbles than most available formulas. The clear casting resins require more setting time up to about 25-minutes. The opaque resins set to an ivory color in approximately 5-8 minutes. The two varieties offered here are opaque and a water clear resin. These polyurethane casting resin products are two-part, 1-to-1 mix ratio formulas that set from 5 to 20-minutes. They are fast setting and our product offerings do not need a respirator as they are very low in odor emission. Then there are polyurethane casting resins. Unlike faster setting polyurethane resins, epoxy resins can take from several hours to several days to completely cure.

Though a respirator is not needed while using epoxy resins, epoxy resins get more expensive the clearer you want your finished casting to be. Because of its health hazards we do not offer this product. Most of us are familiar with polyester resin as it is the binder in fiberglass products – it is the polyester resin that produces the distinct and often off putting odor of fiberglass. However, there are a number of critical disadvantages in that the resin without the addition of fiberglass has poor mechanical properties, it’s emission during use in open molds is considered carcinogenic and it has a high and unpredictable shrinkage rate. The advantage of polyester resin is that it is easy to use and is the lowest cost resin among resin products. Because it does cure very hard, polyester resin projects may break if dropped on a hard surface. In addition, it is not UV light resistant which will cause it to yellow with time. The user must wear a respirator and work with a hood or in a well ventilated area. There are a number of safety issues in using polyester resin as it can be dangerous with its very noxious odor. Polyester resins are contact products which require no pressure to cure and can be cured from a fluid or solid state. The polyester resin used in the molding application is a viscous liquid (like honey) requiring the addition of catalysts and accelerators to complete the curing process. Polyester resin is most commonly used in the construction of molded reinforced fiber and composite products, so its mechanical properties are reinforced with the fiberglass itself. Casting resins fall into three classes, polyester, epoxy and polyurethane resins.

Instacast mold