... this manufacturing process, we can use the following materials: brass, copper, iron, aluminum. 2). Die cast (injection die cast) For ... use the materials: iron, brass, zinc alloy, aluminum, copper. 5). Soft PVC (soft PVC material is only used for this process). 6 ... antique brass, antique copper, etc. 3). Imitation hard enamel --- This process is also called "polished enamel". 4). Soft enamel with clear ...