I am having a problem with warping bases in my paper clay vases.
I use paper clay slabs to build my vases. I dry my vases slowly, covering the body and the top of the vase with a plastic bag. After a few days of drying, I find that the foot has warped and my vase wobbles. Someone suggested that I place the vase on a piece of plaster so that the moisture can be absorbed from the foot, which tends to dry slower than the rest. This didn´t help - it warps either way!
I can often save my vase by sandpapering the base carefully, (yes, I know, the dust) however when I do the bisque firing, the base warps again! I fire to 960° C (100°C per hour).
Does anyone have suggestions? I really don´t know what else to try out....