Modern Wonders of an Ancient Art (Jun, 1936)
Modern Wonders of an Ancient Art
By H. W. MAGEE
Part I PORCELAIN enamel is older than history and yetâ€”in its modern applicationsâ€”it is as new as tomorrow. Fifteen centuries or more before the dawn of the Christian era, someone heated a batch of minerals and produced a glasslike substance which he found could be fused to metal with the aid of heat. In the next two thousand years or so man utilized this knowledge mainly to produce beautiful cloisonne vases, medallions, jewelry and other ornaments.
Then, about a century ago, someone else gave a practical twist to what, up to then, had been a fine art. He coated cast-iron pots and pans with porcelain enamel to produce better cooking utensils. And about 1870, well over three thousand years after porcelain enamel first was produced, another genius applied the same principle on a much larger scale. The result was a bath tub.
Thus was evolved porcelain enamel as we now know it, a product so common you see it and use it without thinking from the time you get up in the morning until you go to bed at night. You bathe in a porcelain enameled tub, eat a breakfast prepared in porcelain enameled pans on a porcelain enameled stove, glance at a clock with a porcelain enameled dial, are reminded you need gas by porcelain enameled signs, pumps and filling stations, perhaps eat your lunch off a porcelain enameled table, drink from a porcelain enameled water cooler, use a telephone with a porcelain enameled dial and, at night, go to the refrigerator for a late snack and encounter porcelain enamel again.
You see solid panels of it in hospitals, barber shops, meat markets and soda fountains, your bathroom and kitchen fixtures are covered with it, and you encounter it in stoves, scales, thermometers, washing machines, name plates, roofing shingles and scores of other articles. And finally, when you die, a porcelain enameled vault may receive your body and a porcelain enameled monument may mark your resting place. Yet, despite the multiplicity of uses which have been found for it, man today is just beginning to realize the full possibilities of this product which he has known for thirty centuries. New applications are being found for porcelain enamel daily and even now it is likely we have not visioned the ultimate results of this union of glass and metal. “When the mile-long tunnel between Detroit and Windsor, Ontario, was dug, porcelain enameled tile provided the lining for it. And porcelain enamel again solved the problem when a lining was sought for railroad cars and trucks carrying milk.
Eight now, if you desire, you can live in a porcelain enameled house, enjoy porcelain enameled furniture and ride on a train coated with the same material. Houses with both exterior and interior walls of colored porcelain enameled metal have been constructed and porcelain enameled furniture already is available while a train with porcelain enameled coaches is being operated abroad.
To understand the many new ways in which porcelain enamel may serve mankind, we must first understand just what it is â€”and what it is notâ€”how it is made and something of its physical properties. In the first place, porcelain or vitreous enamel is not a paint although it often is confused with paints because some lacquers and glossy paints are called enamels.
Porcelain enamel is a thin layer of glass fused or welded on to a metal base, and it is made somewhat like glass. The metal commonly used is a special grade of steel or “enameling iron” and cast iron. The four corners of the earth provide the raw materials which go into porcelain enamelâ€”feldspar, borax, quartz, soda ash, nitrate of soda, fluorspar, cryolite, cobalt, nickel oxide and manganese. The materials are mixed and the mixture is loaded into smelters where it is reduced to molten glass by temperatures as high as 2,200 degrees.
The molten glass is quenched in pits filled with cold water, the sudden change in temperature shattering the liquid glass into millions of granulated particles called “frit.” The frit passes through driers and meshed-screen classifiers, then through magnetic separators to remove any traces of iron which might cause specks or discoloration. Batteries of mills grind the frit, along with water and clay and metallic oxides if color is used until the mass is converted into a creamy liquid. This is porcelain enamel ready for applying.
The metal itself must be thoroughly cleaned in preparation for its glass coat. The ground coat is applied by dipping or spraying, then the porcelain enameled metal passes to a drier and on to a furnace where, at a temperature of around 1,600 degrees, the glass is fired or fused on to the metal. After cooling, the process is repeated as two or more finish coats are applied.
The final result is a piece of metal to which has been welded a flintlike inorganic or mineral substance harder than steelâ€”a durable, lasting finish capable of withstanding the cold of a refrigerator or the heat of a gas range indefinitely. It is non-porous, its surface is easily cleaned, its colors are permanent and, if necessary, it may be made acid-resisting.
Making porcelain enamel today has been reduced to an exact science. Raw materials must | measure up to strict chemical and physical specifications, the frit undergoes further laboratory tests, smelting and firing temperatures are controlled accurately, colors are blended and matched with scientific precision and the finished enameled metal must stand rigid impact, bending and reflectance tests.
Considering the fact that the ancient enamelers worked with crude equipment and without any modern scientific aids, the jewelry and ornaments produced hundreds or even thousands of years ago become all the more remarkable. Skill in both metal working and enameling was necessary to turn out the beautiful pieces now seen mostly in museums. Several types, distinguished mostly by different makeup or construction of the metal base, were produced down through the centuries, cloisonne enameling being the most familiar.
In cloisonne work, the figure or design to be reproduced was outlined with flat strips of metal or fine wire, the edges of the metal being upright so small enclosures or “cloisons” were formed to receive the enamel colors. The wire was attached to the metal base, the little enclosures filled in with the various colors of enamel, and the glass was fused to the base. Then months often were spent in polishing the finished piece. In other types of enameling, the design was often cut into the metal base, the depressions being filled with the enamel.
Strange as it may seem, porcelain enameling which started as a fine art, today again is reverting to artistic applications. Paintings now are being reproduced in full color in porcelain enamel in much the same way that four-color plates are made for magazines. And at least one man has found a process for reproducing a photographic image in porcelain enamel â€”a reproduction which will last not a lifetime, but for ten thousand years.
This color-fast, non-porous, durable and easy-to-clean substance had its practical start in life in the kitchen, then progressed to the bathroom and today is moving into the living room where its infinite hues supply the demand for color. A fireplace of porcelain enamel lends a modernistic touch to the living room, and porcelain enameled tables, jardinieres, decorative columns and light reflectors fit into modern decorative schemes.
The same qualities which make porcelain enamel suitable for home use have brought it out of doors. The cold blasts of the north have no more effect on a porcelain enameled sign or thermometer than have the sunshine and salt-laden air of Florida.
Its newest conquest, however, has been in architecture. Builders were slow to realize that the same qualities which make it suitable for a bath tub, a gas range or a refrigerator also make it a suitable covering for exterior or interior wall surfaces. How porcelain enameled metal is being used today in architecture and its future possibilities in this field is a story in itself.