Clays of very high plasticity often stiffen during storage in the bag. This is Plainsman Polar Ice, it contains 4% VeeGum. This slug is like a brick, yet it will loosen up completely. But it is far too stiff to attempt wedging. However simply throwing it on the floor a few times (turning it each time) will pre-soften it enough to be able to wedge. Then, before you know it, it is too soft and needs to be put on a plaster table to stiffen it before throwing.
In ceramics, clays exhibit plasticity in accordance with their recipe but also the water content. The stiffness considered correct varies for different types of forming methods
|Media||A 3-minute Mug with Plainsman Polar Ice|