Monday, December 13, 2010

Pop quiz time

Well test time at least.

The glazes I used at my last studio didn't transfer well to my latest studio, so it's time to test. I decided to do it right. I made up about three dozen test tiles and I am starting with a blank sheet of paper and what colors I want. The first thing I want is a good black temmoku. I don't want Val's Temmoku Gold. I don't want the crystals, I want a smooth, glossy pitch black temmoku.

So I pulled out all my books (I have a bunch of glaze books) and started reading - why are most cone 6 temmokus full of crystals? How can I get a beautiful fat black tenmmoku at cone 6? I had tried before but failed. I found the answer this time. One little paragraph tucked away in Michael Bailey's "Oriental Glazes". The crystals form when the glaze is low in alumina (duh, like all those glazes that have intentional crystals). So the key is to flux down a cone 10 temmoku while keeping the clay content level with the cone 10 formula AND not overloading the glaze with calcium. So my flux options are adding grestely borate, possibly lithium, replacing the feldspar with neph syn, maybe even adding a couple parts barium carb.

On top of that I have a couple of line tests lined up - trying to figure out what the hell happened to my iron red and what recipe will work in these kilns.

I'll post the actual recipe for the temmoku once I get one that I like.

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