The Use of Brick in America
In America, aside from the adobe construction which the Spanish found in Mexico and Peru, the first brick were brought over from England or Holland. The native industry, however, had an early start in the seventeenth century, so that the Colonial times saw many fine specimens of brick building from New England to Virginia.
In the nineteenth century, up to about 1880, there was no general attempt to use brick to the best advantage. For the most part the brick building of that period was confined to the use of common brick for ordinary construction or for backing stone-faced walls. From that date, however, to the present, a growing taste has demanded and secured artistic effects in the brick wall by the use of specially manufactured face brick which, in a bewildering variety of beautiful color tones and textures, have been sympathetically and artistically treated by our leading architects, as may be seen all over our country.
[MODERN BRICK MAKING]
It is a long cry from the primitive method of mixing and molding brick by hand and drying them in the sun, to the modern technical methods and power machinery used by the American manufacturer. Determined by the kind of material, whether surface clay, fire clay or shale, and the kind of brick wanted, there are three chief methods of manufacture, slop-mold, wire-cut, and dry-press.
By the first method, the clay, in a soft condition, is pressed by the machine into molds which have been flushed with water—hence the term slop-mold—or sprinkled with sand, in which case the brick are called sand-mold. By the second method, the clay or shale is ground and tempered into the consistency of a stiff mud which is forced by an auger machine through a die, in the form of a stiff mud ribbon, having the cross section of a brick. This stiff mud ribbon is carried by a belt to a steel table under a series of piano wires strung on a frame which is revolved by the machine at proper intervals, cutting the clay ribbon into the desired sizes. These stiff mud machines will turn out as many as 100,000 face brick a day, and in some common brick plants they are built for a 250,000 to 300,000 daily output. The dry-press method reduces the clay to a fine granular form which is then, in nearly a dry condition, forced under immense pressure into the proper sized molds.
The brick as they come from the machines are known as "green" and require, except in the case of the best dry-press brick, a certain period of drying before being set in the kilns where, for from five to ten days, depending on the quality of the ware and the general conditions, they are subjected to a process of burning before they are ready to be built into the wall.
Burning the Brick
This process of burning passes through three main stages which require very skillful attention on the part of the burner. First, the water chemically combined with the material must be driven off; then the various impurities of the clay must be burnt out or oxidized; and finally, the ware, except in case of fire clays, must be brought to the point of incipient vitrification. Throughout the whole process there is danger of distortion or discoloration in the ware unless the fires are skilfully handled. Properly done, the brick come out of the kiln in their beautiful, natural colors, due to the constitution of the clay or the various metallic oxides contained in it. To enhance these effects, different clays are sometimes mixed in going through the machines, certain ores may be added to modify the color, the brick surfaces may be scored in various ways, or the ware may be set in the kiln so as to avoid or get the flash of the fire. So that when you specify a fine face brick, you are getting a product which Nature has taken long to create and to which man has devoted his best scientific knowledge and inventive art.