Rock and wood boring are also specialized consequences of burrowing the evolution of borers proceeded from the habitation of stiff muds or from nestling within crevices.
The stiff-mud process offers the most possibilities for texturing brick.
Firebricks are formed by the dry-press, stiff-mud, soft-mud casting, and hot-pressing processes used in the manufacture of building bricks.
In the processing of structural clay products, stiff-mud plastic-forming operations predominate for example, pressing operations for brick and extrusion for brick or pipe (see Figure 1).
In the stiff-mud process the clay is mixed with water to render it plastic, after which it is forced through a die that extrudes a column of clay like the toothpaste squeezed from a tube (see the Figure).
Most clay-based products are processed in a manner similar to other traditional ceramics such as structural clay products; e.g., stiff-mud processes such as press forming or extrusion are employed to form the ware, which is subsequently dried and passed through long tunnel kilns for firing.
Gradually add water and stir the mixture, until you achieve a stiff, workable "mud pie" consistency.
As I approached the halfway point in the event, I was stiff and crusted with mud — and my hands were blistered from plywood and monkey bars — but I felt more confident.
Leaping over bales of hay was fun, but slogging through the back stretch thick with mud was a stiff reminder that I was no thoroughbred.
What would have taken him ten minutes out on the street took an hour at least, his feet unsteady in a slurry of mud and trash, stiff dead reeds knifing at him, dogs barking, the drift of people's voices freezing him in place.
