Business: Better Bricks

Brick masons at East Chicago, Ind., slashed at mortar with their trowels last week, plumped bricks down to form the stringer courses of a 500-foot surface tunnel; pipe fitters twirled threads onto gas lines with their tap-&-die threader; freight gondolas dumped clay and ganister—Harbison-Walker, $36,000,000 brickmaking corporation, was having constructed a new type of kiln to burn silica brick. Corporation President J. E. Lewis had heard of the kiln operating at Dusseldorf, Germany, and after a talk with his Board Chairman H. W. Croft in their Pittsburgh offices had hurried to Dusseldorf to see the kiln in action. He liked it; secured the U. S. rights to its use; immediately had mechanics awork at East Chicago.

The ordinary way of making bricks is to press a mixture of clay, sand and water into forms. Usual size is close to 21¼ x 4 x 8¼ in. Such blocks are dried in the air or in a warm draft. Then they are stacked in a hemispherical kiln usually 30 feet in diameter by 12 feet in height. A yard full of kilns looks quite like a group of dirty red igloos. Their orifices are plugged up and a fire lit under a stout grating upon which the raw bricks are piled. In six to ten days they are burned hard and useful. Their red color is the result of iron in the clay and sand. White bricks come of lime added to a specially prepared clay. Various minerals added to the base clay give “tapestry” bricks.

This fashion of making bricks has great wastage. In the kiln heat a great portion of the bricks warp and curl. Some can be sold for seconds and used in the hidden supporting walls of low grade apartment houses. Most, however, must be crushed and used as road-making filler.

Harbison-Walker in shaping their bricks squeeze their clay or ganister mixture into a long greyish bar which, as it crawls out the mold, resembles a creeping crocodile. A slicer armed with steel wires cuts the firm bar into separate bricks just as a string cuts a bar of Ivory soap in two.

Those raw bricks are to be placed on small cars and slowly passed through the 500-foot tunnel kiln which Harbison-Walker’s President Lewis is having built at East Chicago. In passage they will endure a heat of 2,700° Fahrenheit. (Temperature of boiling water is 212° F.) Spoilage of bricks is expected to be trivial.