|Monthly Tech-Tip |
The water that a plaster table absorbs from clay slurries contains soluble salts. They penetrate into the plaster and then come back out to the surface as the water evaporates, forming a hard and less absorbent layer. Variable absorbency in a plaster surface can easily be observed as it is cleaned with a sponge and water. Fortunately, that layer is very thin and can be removed by sanding. Plaster is durable and can serve for decades using this technique. These durable fabric sand paper screens work exceptionally well because they can be used with water and to not blind. They are available in hardware stores and sold as drywall sand screens. We have seen 150, 120 and 80 grit (the latter is the one used here).
The process of slurrying a clay body powder and dewatering it on a plastic slab or table.