One form of bell making is an intricate and demanding form of metal casting known as the lost wax method. The lost-wax bell casting process is a method of bell making in which molten metal (usually bronze or brass) is poured into a mold created by a wax model of the original bell sculpture. This technique is around 6,500 years old and is thought to date back to 4550–4450 BC.
In this process, a core of clay is formed in the general shape of the bell to be cast. Next, a layer of beeswax is applied to the core and molded by hand into the desired shape. Over the wax form, a thin layer of smooth clay called slip is applied. The slip preserves the fine detailing in the wax. Layers of rough clay are then applied until the entire form is firmly encased in clay forming a mould.
After the clay form has air-dried, it is heated until the wax melts and runs out of the form. This is where the term "lost" wax comes from. The clay is baked hard enough to withstand a pour of molten metal. The metal is then melted in crucibles over a hot fire and poured into the hollow space left by the lost wax. After the metal has cooled, the form is broken open and clay layers cleaned off, leaving the bell which is then polished into a finished piece.
*Image courtesy Takkk - via Wikimedia Commons