a method for preparing a mold form includes forming a mold blank having a surface corresponding to the surface of the article desired and enclosing the mold blank in an open ended enclosure . a thin layer of polymer resin , preferably polyurea is sprayed on the surface of the mold blank and allowed to cure . heat transfer tubing is inserted over the resin layer . a mixture of metallic pellets and epoxy are inserted over the heat transfer tubing and then another layer of resin is sprayed over the mixture . after the resin has cured , the mold blank is removed to expose the mold form having an outer surface of polyurea .