Monday, September 29, 2014

TOO MUCH GAS


I have been making a thickish white slip out of my porcelain slurry for a while now with a touch of soda ash and frit and find myself having a problem with too much gas being released during the firing and sometimes (?) causing pinholes. Since the slurry comes right out of the bucket as is, I have been playing around with ways to help eliminate the problem with mixed results and in one case the slip shivers off the pot after the glaze firing. Using smaller test rings I have made a few alterations and now fire the bisque a bit hotter and for a longer period of time. The last test batch showed promise so I threw a large teabowl this morning that will be my next step following the tested procedure. I also decided to go with a hakeme decoration as that seems to compound the pinholing problem so we will see what happens once the bowl is tooled, dried, bisque, and glaze fired. The more you change things the more they change! Should have paid more attention  to the philosophical concept of cause and effect and how it applies to chemistry, physics and pottery.

"In everything we ought to look to the end."  Jean de La Fontaine (1621-1695)