Short answers, pulled from the story.
The oldest known objects created by the lost-wax method are small gold knucklebones found in the Varna Necropolis in Bulgaria. These artifacts date back to the period between 4550 and 4450 BC, approximately 6,500 years ago. They represent the dawn of a technique that allowed humanity to capture the human form in metal with unprecedented fidelity.
The process begins with the creation of a wax model which is then encased in a heat-resistant ceramic shell. The assembly is placed in a kiln where heat melts the wax, causing it to run out and leave a hollow cavity for the metal. The original sculpture is destroyed to make room for the metal, making the mold a single-use event.
The direct method involves carving a wax model from scratch, while the indirect method uses a flexible rubber or silicone mold to create multiple wax copies. The indirect method allows a single original model to be reproduced many times and was essential for the mass production of religious icons in ancient India and China. This technique also enabled the creation of hollow castings that used less metal and were lighter than solid castings.
The lost-wax technique was used by civilizations across the globe including the Indus Valley, West Africa, the Americas, ancient Egypt, Mesopotamia, Greece, and Rome. Notable examples include the Dancing Girl of Mohenjo-daro, the Benin Bronzes, gold ornaments from the Muisca and Sinú cultures, and bronze statues of the Chola period. The method spread through trade and cultural exchange, adapting to local materials and artistic traditions.
Today the lost-wax process is used in fine art sculpture, dentistry for gold crowns, and the automotive industry for engine blocks. Dentistry uses the technique to create gold crowns and inlays with careful attention to tooth preparation. The automotive industry uses a similar method known as lost-foam casting where polystyrene foam is vaporized by molten metal.