Monday, January 11, 2010

a very big mold

For the past few days I have been casting from a new, very large mold. It was made for me by Silvershell Ceramics, in New Bedford, MA. The mold is so large, I am unable to lift it, and have to "roll" it along the 2x4's to be able to empty out the porcelain slip (liquid clay). It takes five gallons of slip to fill up this mold.

The cast piece emerges as mold parts are removed one at a time.

The mold is made up of three pieces, two sides and a bottom.

The original vase is on the left, I hand-built it with coils a few years back. The black lines indicate the seams for making the mold pieces. The cast vase is on the right, slightly smaller, but in every other way exactly the same. As water evaporates from the clay, the piece shrinks. It will shrink again in the firings, ending up about 10% smaller than the original by the time it is glazed.