Pottery plaster is highly absorbent, it can remove the water from this thick slurry, made from a 5 kg powder mix, in an hour. Slurries of higher water content dewater much quicker, a 1 kg mix can be ready in minutes. This table weighs 400 lbs dry, but smaller ones are equally practical for smaller test batches. Plaster tables are much more practical in arid climates, it is dry here so one this size can supply enough clay for production of a potter. In wetter climates ductwork can be installed within the plaster and air pressure can be used to dewater the table. If you need one of these, photos are linked to our plaster table article.
The process of slurrying a clay body powder and dewatering it on a plastic slab or table.
Slurry Mixing and Dewatering Your Own Clay Body