666 NEW YORK STATE MUSEUM 



; Tlie molded brick are shoved forward on the table by the charger, 

 are placed on cars and either taken to drying chambers or set 

 directly in the kiln. The green brick require great care in handling 

 as they are very tender. Drying must be done very slowly to 

 prevent cracking. Burning is usually done in down-draft kilns. 

 The manner of burning does not differ essentially from that fol- 

 lowed for other makes of brick. By setting directly in the kiln 

 without previous drying it takes longer to water-smoke. This in 

 any case should be done very slowly and the burning should not be 

 pushed till water-smoking is entirely finished. It is calculated by 

 some that one sixth to one quarter more fuel is required to burn 

 dry clay bricks than those made by other processes. Burning in a 

 down-draft kiln is more expensive than in an up^-draft one, but 

 a much greater percentage of good bricks is obtained. It is conse- 

 quently better for burning pressed brick. 



The type of kiln used varies. 



It is essential for the production of good dry pressed bricks that 

 the moisture contents of the raw material shall be pretty constant 

 and the degree of fineness shall always remain the same. The first 

 condition is obtained by drying the clay in sheds, the second by 

 screening the material, after it is ground. 



The manufacture of brick by the dry press process has certain 

 advantages over the stiff mud or soft mud process. 



1 Drying racks and drying sheds are not needed, which means 

 a certain saving of capital and cost for repairs. 



2 The production of brick by this method is cheaper, and the 

 bricks produced have a more constant and even form. 



3 Labor is cheaper than in the case of the other methods, as 

 there is less handling to be done, the bricks being carried directly 

 from the molding machine to the kiln. 



The forms of the bricks molded on dry press machines are not 

 restricted to rectangular shapes, but ornamental patterns can also 

 be produced, which in the case of plastic methods can be formed 

 only in plaster molds. 



