Clay Processing

Preparation of clay for brick manufacturing involves a number of steps, depending on the type of clay being used. Many clays were "weathered" by frost, wind, rain, and sun in order to decompose pyrite and expose iron nodules for removal. After weathering, the clay was "dry crushed" to pulverize clumps. A variety of machines were used to crush the clay, including corrugated crushers or an edge mill crusher. Dry pans had wheels weighing 2,000 to 5,000 pounds, which ground the clay above a perforated plate and let the material drop through when sufficiently ground. Disintergrators had drums or knives revolving opposite each other to pulverize the material.

Other methods also were used to crush or "temper" wet clay. Soak pits were filled with clays and water and left overnight. The clay was then shoveled into molding machines. Ring pits were circular pits with a large iron tempering wheel, which traveled (by horse or steam power) around the pit and also back and forth in smaller revolutions to mix the clay before it went to the molding machine. Pug mills were cylindrical troughs that had knives set at variable pitches in a spiral around the cylinder. The knives cut up the clumps and mixed the clay. Wet pans were similar to dry pans but they had solid bottoms and mix and crush at the same time. In 1904, 60 percent of the New Jersey brick yards were using ring or soak pits (Ries and Kummel, 1904: 223-226, 246). Clay mixing was carried out at S & F Company in a number of mixing rooms.