ENAMELING is an art form and process of bonding glass to metal by the application of heat. Over the course of history, “techniques” of enameling have developed that define: (1) ways in which the enamel is prepared and applied, (2) ways in which the metal base is treated and prepared before enamel application, and (3) the “look” of the finished enamel creation. Some of these techniques have acquired names that often describe a technical aspect of a particular technique.
Several metals can be enameled, although each metal has advantages and drawbacks. Historically, the most commonly used metals for art objects and jewelry are copper, silver, and gold. Each metal can be adapted to certain enameling techniques more easily than others.
The material called ENAMEL is a type of glass consisting of (1) silica, (2) formulas of metal oxides for color, (3) lead oxide (or a substitute), and (4) alkali compounds such as soda, salts of potassium, and borax. The mixtures are formulated technically to address color, flow or melting point, thermal expansion rate, bonding, elasticity, wetting properties, clarity, and surface quality. Commercial production of enamels is a complex, delicate industrial process with carefully guarded technical secrets.
FIRING of enamel frequently takes place in an enameling furnace or KILN, ordinarily in a temperature range of 1300 to 1600 degrees Fahrenheit. Firings can be anywhere from 20 seconds to 10 or more minutes, depending on the enameling technique, nature of the furnace, enamel used, particle size, metal used, and size of the object. The actual length of time of a firing is a judgment made by the enamelist and is rarely a matter of simple formula. A single object may be fired one time or many times depending on complexity of the project and desired appearance. Enamel objects are sometimes also fired using a torch.