In craft art, we often come across a piece of finely formed artwork that bears an uncanny resemblance to another object. How did that metal or glass come to perfectly take on the complexity of an engine, or in the case above, the delicacy of a cotton bloom?
While some silversmiths fabricate metals - typically cut and then construct - others cast their pieces using a process called lost-wax casting. The art of lost-wax casting has been used for thousands of years to produce complex objects in metal. The process can be used with any material that can burn, melt, or evaporate to leave a mold cavity.
Natural objects are some of the most attractive objects we can recreate through the lost-wax casting process; they embody characteristics and personalities that our limited hands are unable to craft. Organic materials possess the ability to completely disintegrate by burning, which lends well to the lost-wax technique. There is no need for an artist to attempt a wax replica.
At the start of the casting, the natural object is attached to a pour-cup with rods of wax called gates or sprues; the pour-cup is a funnel-shaped cup that channels the metal into the mold, with the help of the gates. A venting system is made the same way to convey air and other gasses out of the mold when it is filled with hot metal. Once the model is set up with its gates and vents, it is surrounded with a plaster mixture. Plaster is ideal in the casting process because it will cover the object smoothly when wet and withstand high temperatures when baked.
The plaster sets hard and the flasks are placed in a kiln - slowly reaching temperatures over 1000 degrees Fahrenheit – where it rests until all wax/natural residues have disappeared. The place where the object was once fixed is now void of any material.
The metal is then melted and the molds are filled with liquid. The flask cools and the plaster mold - broken away - reveals the faithfully detailed metal object.
Last week to see "Light and Shadow Dance": Jewelry Art Exhibition, featuring jewelry created by the lost-wax casting method. Exhibit closes September 12.
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