Annual report of the Regents . dry pressed bricks thatthe moisture contents of the raw material shall be pretty constantand the degree of fineness shall always remain the same. The firstcondition is obtained by drying the clay in sheds, the second byscreening the material, after it is ground. The manufacture of brick by the dry press process has certainadvantages over the stiff mud or soft mud process. 1 Drying racks and drying sheds are not needed, which meansa certain saving of capital and cost for repairs. 2 The production of brick by this method is cheaper, and thebricks produced have a mo
Annual report of the Regents . dry pressed bricks thatthe moisture contents of the raw material shall be pretty constantand the degree of fineness shall always remain the same. The firstcondition is obtained by drying the clay in sheds, the second byscreening the material, after it is ground. The manufacture of brick by the dry press process has certainadvantages over the stiff mud or soft mud process. 1 Drying racks and drying sheds are not needed, which meansa certain saving of capital and cost for repairs. 2 The production of brick by this method is cheaper, and thebricks produced have a more constant and even form. 3 Labor is cheaper than in the case of the other methods, asthere is less handling to be done, the bricks being carried directlyfrom the molding machine to the kiln. The forms of the bricks molded on dry press machines are notrestricted to rectangular shapes, but ornamental patterns can alsobe produced, which in the case of plastic methods can be formedonly in plaster molds. Plate 35 To face page G66. SECTIONAL SIDE VIEWOF DRY PRESS BRICK PLANT CLAYS OF ^;EW YORK 667 Semi-dry processThis differs but little from the dry process. The clay usuallyhas a slight amount of moisture added to it. Clays adaptable to the different molding methods Few clays give good results with all the methods of molding justdescribed, and the same clay will not necessarily make a good brickwith any machine of the same general type. This is specially trueof stiff mud machines. For the dry press process a wide range ofclays can be used, for it works with sandy ones, or mth plasticmaterials. Coarse sandy clays however do not lend themselvesreadily to dry pressing, on account of their very slight cohesivestrength. As an illustration of the wide range of clays used, we may com-pare the two following clays, no. 1 being a clay used to a largeextent for making brick in western Illinois, no. 2 a black clay fromWyandance, L. I. Both feel gritty, but neither contains particles large enou
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