Materials and Technologies

Casting and Shaping Metal

During the past few centuries metal has become the predominate medium for producing religious sculpture in the Himalayas.

Metal is shaped primarily by way of hollow or lost-wax casting and embossing, also known as repoussé. Both these methods thrive in Nepal, where craftsmen have formed workshops that specialize in these techniques and cater to Hindu and Buddhist patrons. The choice of creating an image by casting versus embossing is often an economic one. Given that casting requires more metal, large images and architectural decorations are usually made by embossing.

Embossing

In embossing, sheets of soft, malleable metals, such as gold, silver, lead, or copper, are hammered over designed forms (matrices) of wood and other materials, heated for malleability (tempered), and hammered again until they assume the intended form. Large, complex sculptures are created in parts and later assembled with the help of fasteners (rivets) and soldering, or by fusing them together. Some small parts can be cast as well. Artists employ chiseling and sometimes chemically coat the surface with gold, or gilding.

Objects in the Exhibition

Process of Lost-Wax Metal Casting

The lost-wax technique of hollow metal casting, perfected by Newar artists of Kathmandu Valley, has remained a thriving practice from ancient times to the present day.

Stage 1

Artisans start by creating a wax model. They melt a combination of beeswax, vegetable oil, and tree resin into sheets from which parts of the whole figure are molded. These pieces are put together to make a wax version of the figure.

Stage 2

They make the clay mold by coating the inside and outside of the wax figure with several layers of fine and coarse clay. The first layer, mixed with cow dung, is the most important for ensuring the best casting. This is the longest stage, as each layer must dry before the next one can be applied. The coarse clay is mixed with rice husks and applied in layers. When the clay mold has dried, the artisans make an opening at the base so the melted wax can be poured out and molten metal poured in.

Stage 3

The actual casting process begins by melting the wax figure and draining it out of the mold. Once drained of wax, the clay mold is baked, making it hard and ready to receive the molten metal.

Stage 4

Hot metal is poured into the mold. Once it cools, the artisans break the mold to reveal the metal sculpture inside.

Stage 5

They weld the rough metal statue to fix any casting imperfections, chisel it to reveal details, then buff and gild the surface. Each task requires specialized skills and is performed by several people.

Stage 6

Artists paint and decorate the sculpture with semiprecious stones. The statue is ready for consecration, the ritual by which the deity comes to inhabit the image.

Objects in the Exhibition