Tuesday, June 22, 2010


I have been making pots long enough now that I have inherited misc. supplies from various sources. While at Cleveland State the university co-op went under and they gave away a large amount of chemicals and clay. I got quite a bit of colorants, stains and glaze materials that I could use and squirrel away. After leaving CSU, I was lucky enough to get materials from various sources, potters retiring, leaving clay, etc. and I was able to put together a constant pool of usable materials and things I knew were no longer mined and a bit out of the ordinary. I still take every opportunity to get ‘free” stuff whenever the chance presents itself.

Back while at CSU, I used copper sulfate and cobalt sulfate on porcelain with some interesting results. Having recently inherited a small amount of cobalt sulfate I thought to try it out with my ash glaze and see what would happen. I mixed the cobalt sulfate with gerstley borate at 1:1 and mixed it up watercolor thin. I painted a small band around the lip of a teabowl and fired it along with the rest of my pots.

The results surprised me a bit. It ran with long tendrils down the bowl, nearly four inches. Considering the less that ¼” band I painted on the lip, I will need to keep in mind the potency of cobalt in general and the running qualities of the cobalt sulfate/gerstley borate mix. It does make for a rather fluid surface and definitely accentuates the vertical nature of the bowl.

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