Granite or other stone powders are added to polyester resin, polyurethane resin, epoxy, gypsum cement or other binders. Small objects are cast and cured in suitable molds. To conserve the granite or stone powder when casting large pieces you can dust (salt) the mold surface, brush a thin coating on the surface, spread or roll the powder on or spray a thin coating. The mold is then back filled with resin or fiberglass, iron or steel shot, sand or calcium carbonate to increase the weight to give it the heft and feel of a hot foundry ‘pour.’ You can also lighten the piece by added hollow glass beads to your back up casting mix. After curing and removal from the mold, the object must be gently abraded or burnished with fine steel wool (triple 0 grade), a Scotch Brite® pad, or sand blasted to remove the microscopic film of binder from the surface of the granite particles. This exposes the pure stone beneath. Click here to download information of creating cold casting pieces. The object will have the authentic look and feel of a granite carving. That is because the surface is now true granite.
