Man-woman sculpture “Couple” by Stefanie von Quast, sculpture made of red cast bronze

An alloy of copper with other metals (primarily tin), used since antiquity. An ideal metal for high-quality art castings, lasting for millennia. For bronze casting, the artist typically employs a process over 5,000 years old: the lost-wax casting method. It is the best, but also the most elaborate, method for producing sculptures. First, the artist creates a model of their sculpture. This 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, fitted with sprues, and dipped into a ceramic slip. The ceramic slip is fired in a kiln, causing the wax to melt out (lost-wax casting). Now, the negative mold is finally complete, into which the molten bronze, heated to approximately 1400°C, is poured. After the bronze has cooled, the ceramic shell is broken open, revealing the sculpture. Now the casting channels are removed, and the surfaces are polished, patinated, and numbered, either 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 it does not achieve the surface finish and quality of the more elaborate lost-wax casting process.