Art in bronze and brass

Art in bronze and brass dates from remote antiquity. These important metals are alloys, bronze composed of copper and tin and brass of copper and zinc. Proportions of each alloy vary slightly. Bronze may be normally considered as nine parts of copper to one of tin. Other ingredients which are occasionally found are more or less accidental. The result is a metal of a rich golden brown colour, capable of being worked by casting — a process little applicable to its component parts, but peculiarly successful with bronze, the density and hardness of the metal allowing it to take any impression of a mould, however delicate. It is thus possible to create ornamental work of various kinds. The process of casting in bronze and brass is known as cire perdue, and is the most primitive and most commonly employed through the centuries, having been described in by the monk Theophilus, and also by Benvenuto Cellini. Briefly, it is as follows: a core, roughly representing the size and form of the object to be produced, is made of pounded brick, plaster or other similar substance and thoroughly dried. Upon this the artist overlays his wax, which he models to the degree required in his finished work. Passing from the core through the wax and projecting beyond are metal rods. The modelling being completed, called lost-wax casting, the outer covering which will form the mould has to be applied; this is a liquid formed of clay and plaster sufficiently thin to find its way into every detail of the wax model. Further coatings of liquid are applied, so that there is, when dry, a solid outer coating and a solid inner core held together by the metal rods, with the work of art modelled in wax between. Heat is applied and the wax melts and runs out, and the molten metal is poured in and occupies every detail which the wax had filled. When cool, the outer casing is carefully broken away, the core raked out as far as possible, the projecting rods are removed and the object modelled in wax appears in bronze. If further finish is required, it is obtained by tooling.