Abstract: A method of forming a metal mold or die from a model of the mold contours. A workpiece for the mold is coated with a material which is resistant to an acidic etchant, and is then immersed in the etchant and brought into contact with a template for the metal mold or dies. Those portions of the coating contacted by the template are displaced until the template contacts the surface of the workpiece. The template is then withdrawn to permit the echant to etch any portions of the workpiece exposed by displacement of the coating. The process is progressively repeated until the surface of the workpiece conforms to any contouring of the surface of the template.

Abstract: A method of preparing a template for a product from a sample of the product. The ultimate template is either larger or smaller in size than the sample. Initially, a mixture of liquid rubber and a curing agent is prepared. The sample is then covered with the mixture and the mixture is permitted to harden to form a temporary mold. The sample is then removed from the mold to form a cavity, and the size of the cavity in the mold is altered to either increase or decrease its dimensions. Finally, a hardenable material, such as an epoxy resin, is poured into the mold to form the template. If an enlarged template is to be formed, the size of the cavity of the mold is increased by immersing the mold in an organic solvent bath. If the size of the mold is to be decreased, an organic solvent is added to the mixture before formation of the mold, and after the mold has been formed, it is heated to shrink the size of the mold.