Mann-woman sculpture "Couple" by Stefanie von Quast, sculpture made of red casting bronze

An alloy of copper with other metals (especially tin), used since ancient times. It is an ideal metal for high-quality art castings, lasting for thousands of years. When casting bronze, the artist typically uses a process that is over 5,000 years old: the lost-wax casting method. It is the best, but also the most complex, method for creating sculptures. First, the artist creates a model of their sculpture. This model is embedded in a liquefied silicone rubber compound. Once the material has solidified, the model is cut out. Liquid wax is poured into the resulting negative mold. After cooling, the wax cast is removed from the mold, provided with sprues, and dipped into a ceramic mass. The ceramic mass is hardened in a kiln, causing the wax to flow out (lost-wax casting). This creates the negative mold, into which the molten bronze, heated to approximately 1400°C, is poured. Once the bronze has cooled, the ceramic shell is broken, revealing the sculpture. The sprues are then removed, and the surfaces are polished, patinated, and numbered by the artist himself or by a specialist according to his specifications. This makes each casting an original. For lower-quality bronze castings, the sand-bed casting process is often used, but its surface finish and quality cannot match the more complex lost-wax casting process.