PRODUCTION OF MULTI-LAYER BASE METAL

PURPOSE:To improve appearance and to eliminate thoroughly exfoliation of respective layers after production by laminating and uniting plural noble metals by a casting method without using welding, etc. thereby making the boundaries between the respective layers distinct. CONSTITUTION:A molten metal for the 1st layer is cast into a casting mold d1 formed by using a prototype b1 for the 1st layer to form a base metal a1 for the 1st layer. Only the prototype b2 is removed from a rubber mold e2 formed by attaching the base metal a1 to the prototype b2 for the 2nd layer, thus manufacturing a casting mold d2. A molten metal for the 2nd layer is cast into the mold d2 to form a base metal a2 for the 2nd layer united to the base metal a1. A base metal a3 for the 3rd layer fitted tightly and united to the base metals a1, a2 of the 1st layer and the 2nd layer is thereafter formed similarly until finally a multi-layered base metal A is completed.