Bronze Foundry London
The Crucible Foundry
Materials
Bronze
Bronze is a copper-based alloy, traditionally containing tin, although silicon bronze is widely used in contemporary sculpture casting. Depending on its composition, bronze generally melts between approximately 900°C and 1,050°C. Its excellent casting properties make it particularly suitable for sculpture, architectural details, furniture, staircases and decorative metalwork. The lost-wax process allows intricate forms and fine surface textures to be reproduced accurately, with individual cast sections subsequently welded, chased and finished by hand. Bronze can be polished to a bright metallic finish, brushed, textured or chemically patinated using heat and chemical solutions to produce browns, blacks, greens, blues and other colours. The selection of alloy, casting method and surface treatment depends on the intended appearance, function and environment of the finished work.
Silver
Pure silver has a melting point of 961.8°C, although sterling silver, an alloy containing 92.5% silver and typically 7.5% copper, melts over a range of approximately 780–900°C. The addition of copper increases its hardness and makes sterling silver more suitable for functional objects. Silver can be worked through traditional silversmithing techniques, including raising, forming, soldering and fabrication, or cast using the lost-wax investment process to reproduce complex sculptural forms. It is used for sculpture, tableware, presentation pieces, jewellery and decorative objects. Finishes range from highly polished and reflective surfaces to satin, brushed, hammered and textured treatments. Controlled chemical oxidation can also produce darker surfaces, often selectively polished to highlight raised details. Understanding how silver responds to heating, working and finishing is particularly important when combining cast and fabricated components.
Gold
Pure gold (24 carat) melts at 1,064.2°C and is exceptionally malleable, making it suitable for both casting and the production of extremely thin gold leaf. For greater strength, gold is commonly alloyed with other metals: 18-carat gold contains 75% gold, while 9-carat contains 37.5%. The melting range varies according to the alloy and its proportions of copper, silver, palladium or other constituents. Gold can be cast using lost-wax investment techniques, fabricated, soldered or applied as a surface finish through gilding and electroplating. Solid gold is used for jewellery, small sculpture and decorative objects, while gold leaf provides a practical method of finishing larger works without the cost or weight of solid metal. Surfaces may be highly polished, satin-finished, textured or gilded, with the choice of technique determined by the substrate, location and intended appearance. Unlike silver and copper alloys, pure gold is highly resistant to oxidation and tarnishing.
