|Monthly Tech-Tip |
The more plastic a clay is the more pieces of a given size can be made from a box (boxes are 20kg or 44 lbs). Each mug thus required 500g of pugged clay. These have been trimmed and engobed (using our standard L3954B cone 6 engobe) and are drying (the trimmings left over are enough to make about two more). Notice I have waxed the outers of some of the handles to slow their drying (to keep it in sync with the mug itself). M390 is likely the most plastic native Plainsman body. Although it was not overly soft I stiffened up the clay for ten minutes on a plaster bat to make it my ideal stiffness for throwing.
This is from half a box! 21 mugs from 10 kg ( (all scrap was reclaimed). Polar Ice porcelain double the price of others. Why use it? Because it is so plastic that you can make more pieces, many more, enough to more than pay the extra clay cost. And you can charge more for each piece. These have a weight-to-capacity ratio of 1.09. That means the mug itself is lighter than the weight of water it can hold (each 1 gram of fired porcelain can contain 1.09 grams of water). This is much better than most other clay bodies.
Plasticity (in ceramics) is a property exhibited by soft clay. Force exerted effects a change in shape and the clay exhibits no tendency to return to the old shape. Elasticity is the opposite.