This specification covers the standard requirements for commercial zinc casting alloys in ingot form for use in the manufacture of sheet metal forming dies, sand cast or plaster cast forming dies, and plastic injection molds. Kirksite A alloy (UNS Z35543) is intended for use in the fabrication of dies for sheet metal stamping under drop hammer and hydraulic pressure while Kirksite B alloy (UNS Z35542) is a special purpose alloy of closely controlled composition and is primarily used in the manufacture of plastic injection molds. The alloys may be made by any approved process and shall be of uniform quality and free from dross, slag, or other harmful contamination. Jumbo or block ingots shall conform to the configuration, or to a shape and size previously agreed upon. Conformance with the composition requirements for aluminum, cadmium, copper, iron, lead, magnesium, tin and zinc shall be determined by spectrographic or chemical analysis. The samples for chemical analysis shall be taken from the material by drilling, sawing, milling, turning, or clipping a representative piece or pieces of the ingot.