Exterior decorative parts stamped from aluminum were lighter than similar chromium-plated zinc castings. Over 60% of all metal castings are produced via sand casting process. The total weight of metal castings and forgings used in the aircraft was only . It had large pistons built of aluminum and magnesium castings with steel-plated cylinder linings. A foundry is a factory that produces metal castings. Reverberatory and crucible furnaces are common for producing aluminium, bronze, and brass castings. These would be replaced by less expensive castings and stampings where possible. Other applications are in electrical batteries, small non-structural castings, and alloys such as brass. Zinc alloy castings offer the advantage of low cost. It can be used as a release agent for plaster molds and castings. It incorporated many lightweight castings made from Elektron, an expensive magnesium alloy. Unlike standard die castings, these castings can be heat treated and welded. It is also used for any steel castings. The casing is a pair of light alloy castings. New larger frame castings reduced the amount of frame welding.