Firing today
When I began firing my reduction kiln, I had some difficulty in determining the correct amount of reduction for my glazes. I struggled with it for a couple of years, with uneven results, and then I purchased an Oxy Probe. The probe is a device to provide information on the amount of reduction or oxidation during each stage of the firing cycle. Initially I found it useful, but it broke after about 2 years – I fixed it, and then it broke again about a year later. They’re pretty expensive to repair, and I decided to change my firing cycle so that I began reduction after dark. While firing at night can be inconvenient, I now feel that I get a better sense of the reduction from the color and intensity of the flame at the ports, than I did with the probe. I can also monitor the burner ports to ensure that the damper setting doesn’t cause the flame to back up out of the port.
I begin reduction at about 012 on the bottom and 010 at the top, and continue a medium (no smoke) reduction until 09 is down at the top. My kiln is a Bailey 18 cubic foot stackable forced air kiln. It tends to fire hotter at the top during oxidation and hotter at the bottom during reduction, so when I begin reduction the top is a bit hotter and after reduction the bottom is somewhat hotter. When I shut it down after the final clearing oxidation, it’s usually 10 flat at the top and 1/2 at the bottom, sometimes a bit closer. I’m generally happy with the results, but then again, I’ve grown accustomed to the issues of a forced air kiln which I will discuss in a future post.
So for today, it’s firing, paperwork, and clay preparation. I need to begin making new pieces tomorrow.