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Author: Admin | 2025-04-27
Halves were made first of stone, then of clay.Claudio Cavazzuti, University of Bologna, demonstrates the process of creating a sandstone mold for casting an Early Bronze Age axe (https://www.youtube.com/watch?v=g5npVVVyWYg).What are the advantages and disadvantages of using molds for casting?What skill set would craftsmen need to possess in order to cast in molds?For intricate forms, or for producing parts of larger objects, a new technique was invented ca. 3000 BCE—the “lost wax casting approach.”The “lost wax” technique allows for the casting of objects with complicated shapes. The details of that shape are initially rendered in wax, after which the negative space created by melting the wax is filled with molten bronze (1,600 degrees Fahrenheit). This technique also allows for the casting of larger objects, including bronze statues, several components of which could be cast in a sequence of “lost wax”-casting events. During the Renaissance (late 15th century CE), the indirect lost-wax technique was developed, which made it possible to make copies of statues. The surface of the statue was divided mentally into different parts, and covered in clay placed over the designated segmented areas, much like a jigsaw puzzle around a 3D object. When the pieces hardened, the statue was removed, and the pieces reassembled and securely bound together. The empty space was filled with molten wax to create what is known as an “intermodel.” After the latter was freed from the piece mold, wax rods (sprues) were attached perpendicular to the surface of the intermodel to serve as the vents for the evacuation of air and gasses during the casting process. Another layer of clay was placed over the intermodel and the whole structure was baked to melt the wax. The resulting mold was then filled with molten metal, as in the traditional “lost-wax” technique.One of the first free-standing bronze statues since Antiquity, Donatello’s David (1440s), now at the Bargello Museum in Florence, was cast in this manner. Bronze casting, however, is used not only by artists, but also to preserve original works of art. Leonardo da Vinci’s horse (known as Gran Cavallo), for example, was part of an equestrian statue of the duke of Milan, Ludovico il Moro (1494–1499), but the artist never managed to finish the work. The statue was meant to be the largest equestrian monument in the world. Based on Leonardo’s sketches, two full-size bronze casts were produced in 1998, one of which is now in
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