Metalworking

Metalworking is the craft and practice of working with metals and alloys (brass, bronze, copper, iron etc.) to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large sculptures, artifacts to jewelery.

Metalworking generally is divided into the following categories: forming, cutting, and, joining. Each of these categories contain various processes.

LOST-WAX CASTING:

It is an ancient process by which bronze or brass is cast from an artist's sculpture.

1. Sculpting: An artist creates an original artwork from wax, clay, or another material. Wax and oil-based clay are often preferred because these materials retain their softness.

2. Moldmaking: A mold is made of the original sculpture. Most molds are at least two pieces, and a shim with keys is placed between the two halves during construction so that the mold can be put back together accurately. To preserve the fine details on the original artwork's surface, there is usually an inner mold made of latex, vinyl, or silicone which is supported by the plaster part of the mold. Usually, the original artwork is destroyed during the making and initial deconstruction of the plaster mold. This is because the originals are solid, and do not easily bend as the plaster mold is removed.

3. Wax: Once the plaster-and-latex mold is finished, molten wax is poured into it and swished around until an even coating covers the inner surface of the mold. This is repeated until the desired thickness is reached.

4. Removal of wax: This hollow wax copy of the artwork is removed from the mold. The artist may reuse the mold to make more wax copies, but wear and tear on the mold limit their number.

5. Chasing: Each hollow wax copy is then "chased": a heated metal tool is used to rub out the marks that show the 'parting line' or 'flashing' where the pieces of the mold came together. The wax is 'dressed' to hide any imperfections. The wax now looks like the finished bronze.

6. Spruing: The wax copy is "sprued" with a treelike structure of wax that will eventually provide paths for molten bronze to flow and air to escape. The carefully planned spruing usually begins at the top with a wax 'cup', which is attached by wax cylinders to various points on the wax copy.