Monthly Archives: September 2015

Orange-red bowl – distorted

I am still working on how to consistently get this gorgeous orange red. This is a potash feldspar/bone ash glaze with additions of iron oxide, as Michael Bailey sets out in his book Glazes, cone 6, 1240°C. He shows the gradations of colour obtained by increasing the amount of iron oxide by 1% each time.

Of course, there is always more to it than meets the eye. I’ve managed to get some wonderful results on test pieces, using 6%, 8% and 12%, but they don’t replicate on full-size pots, at least not consistently and not both inside and outside… Sometimes a thin layer of glaze is bright and successful, but when I actually dare to use on a piece, it’s all rather disheartening: often it comes out of the glaze kiln a dirty brown. And since I use shared workshop space with others, I am limited to the kiln temperature used by the group, 1260°C (so considerably higher than the specified cone 6).

Starting again this month, I have gone back to another workshop, where my former maître, Alain Losa, is teaching. They fire at 1250°, so closer to cone 6. I’m hoping that by re-doing my tests, measuring the specific gravity of the glaze, and picking his brains, I can make this work. People like orange-red, so if at first you don’t succeed…

So, you may be asking, how did you manage to get this glossy orange-red?

Luck. I refired the inside of this distorted (not bad, but in my opinion dirty brown) bowl a couple of weeks ago, recoating the inside with an orange-red at 12% iron oxide (I’d used 8% the first time). I did nothing to the outside, as it was pretty good as it was. I’m happy this time.

Fired in oxidation, to 1260°

At The Pond : ridged stoneware vase, distorted (ht: 17cm, w 21cm)

This is a vase which I made a while ago, but that I never got around to posting. I will do so now, as I am going to miss it: it is going to a new home.

It was quite intriguing to make: I threw a cylinder, then opened it out. I let it dry a bit, but to less than leather-hard. Centering it back on the wheel, I used my index finger to make the grooves/ridges. Then, standing and leaning over it, I used one hand on the inside only (I couldn’t touch the outside without damaging the surface) to force the clay out, and up, five times, each hand movement creating a  raised bump on the shoulder as it came to the finish.

After bisque firing, I glazed it. First, I poured an iron-rich tenmoku glaze into, and back out of the vase, leaving a good thickness extending over the rim. After having left it to dry, I poured  T14 (a Michael Bailey transparent base glaze) over the whole piece twice, giving the varying depths and movement of the glaze as it flowed over the ridged surface. The greeny-yellow tint comes from additions of nickel, titanium,and tin oxides.

It makes me think of a pond in springtime, sunshine over murky water, rimmed with mud.

Fired in oxidation, to 1260°C

Reverse:reverse-ridges-distorted-yellowy-green-vaseFSCN3017