Bronze sculpture is the most numerous form of cast metal sculptures as a result of a characteristic trait which is as unusual as it is desirable. Commonly used bronze alloys will expand a little just before being set so that even the finest details of a mold are filled.
Bronze sculptures are also strong while ductile, or lacking in brittleness, allowing figures to be depicted in actions such as leaps and flights. Supports for bronze statues require smaller cross-sections because of such qualities, as may be seen in equestrian statues where only two hooves are on the base.
Today’s examples are generally created of ninety percent copper and ten percent tin, while in antiquity bronze works were occasionally made with other elements such as phosphorus, manganese, aluminum, or silicon. Interestingly, far more stone and ceramic works have come down to us through the ages than those made of bronze, as the metal was very precious and often melted down to produce new sculptures or weapons and armor in times of war.
Thus, really few big examples in bronze are available from ancient times, and of these most are not in great condition. Indeed, most works exhibited in museums, while still full of the evidence of wear and tear, have been painstakingly restored to a quality suitable for display.
Working successfully with bronze usually requires a high level of skill, and a number of distinct casting processes might need to be employed, such as lost-wax casting and the related modern-day technique of investment casting. Other methods include sand casting and centrifugal casting.
After final polishing, corrosive materials might be applied to bronze works in order to form a patina or film produced by oxidation or some other chemical method and establish some control over the color and finish. For example, reactive chemicals may be applied to produce a novel marble-like appearance.
