What Is Vitreous Enamel?
(Vintage Thompson’s 676 Red Raspberry on Silver Foil)
Vitreous enamel is glass bonded by fusion to a metal surface. The most common glass is a fusion of silica, soda, lime, and a small amount of borax. Though normally transparent, various amounts of opacity can be produced by adding or growing crystals within the glass structure. A wide range of colors are produced by incorporating certain elements, mostly transition metals. The physical properties of glass can be control- led to permit bonding to most metals, for example, gold, platinum, silver, copper, steel, cast iron, aluminum, and titanium. The word “Enamel” refers to the glass material, as well as to the finished product.
Enamel (Glass) is crushed to a powder somewhat finer than granulated sugar and somewhat coarser than flour. This powder is applied, by one of several methods, to the metal surface. Next the article is heated to 1000-1600°F, either in a preheated furnace, or with a hand held torch. After 11/2 to 10 minutes the article is removed and allowed to cool to room tempera- ture. Subsequent coats, normally different colors are applied. Sometimes 10-20 firings are required to bring about the desired results.
We do not know when or where enameling originated. The earliest known enameled arti- cles are six enameled gold rings discovered in a Mycenaean tomb at Kouklia, Cyprus. The rings date from the thirteenth century B.C. The Greeks were enameling gold Jewelry as early as the 5th Century B.C. Caesar found the Celtic inhabitants of Britain enameling in the 1st Century B.C. During the Byzantine era, 4th through 12th Centuries, numerous enamel religious works were made. Fifteenth Century artisans in Limoges, France perfected the use of enamels in a painting technique. The 17th, 18th, and 19th Centuries and the early decades of the 20th, saw the production of a great volume of luxury and decorative enamels, made in many different centers. Since the last third of the 19th Century both Japan and China have exported an abundance of enamel as cloisonné – the name of the technique. Starting early in the 19th Century it was realized enamel could be used for utilitarian purposes. First on pots and pans for cooking, then stoves, refrigerators, kitchen sinks, bath tubs, home laundry appliances, architectural panels, etc.
A quality work of enamel art should have a sense of design, a feeling for proportion and appropriateness of color and texture. Transparent enamels should be jewel-like. Firing of all enamels should be sufficient to insure a permanent bond of glass to metal. The work should show that the artist has full control of the technique and materials.