156 



NEW YORK STATE MUSEUM 



Molding 



Soft mud machines 



( Hand power 

 < Horse " 

 ( Steam " 

 j Auger 

 ( Plunger 



Drying. 



i 



Stiff " 

 h Dry clay 



Open yards, sundried 

 Covered yards, air dried 

 Pallets 



r Steam pipes circulating 

 within 



| Tunnels heated by -j iE ^ kl&st 

 I J j Hot air from coal fire 



| through flues under- 



L neath 



Burning kilns 



{ 1 VUC UI J_U.<JXC 



Rectangular chimne . 

 Circular 



b Up draft 



j Scovekilns 

 1 Clamps 



One or more 

 chimneys ac 

 cording to make 



Soft mud process 



Preparation of the clay. — This step in the manufacture of 

 clay products is of great importance, and on it success or failure 

 often depend. JSo fixed rule can be laid down for the prepara- 

 tion of all clays. Two clays may have a similar chemical com- 

 position and yet their physical condition may be such as to 

 necessitate entirely different modes of treatment. A particular 

 clay may give the finest quality brick by the soft mud process, 

 while if molded in a dry clay machine it will produce a brick that 

 is absolutely worthless. There are clays on the other hand 

 which make a good brick by several methods. In any case, 

 however, whatever the method or the clay, it should be pre- 

 pared, and the more thoroughly this is done the better. Many 

 advocate weathering the clay. This will break up the clay and 

 thereby lessen somewhat the expense of mixing but does not add 

 to the quality of the finished product. 



In the soft mud process the clay is usually prepared either in 

 soak pits, ring pits or pug mills. 



