Monday, July 11, 2011

Too Much Oxidation?

I'm afraid I may have burned off many of the nice effects from firing in a wood-fired kiln when I decided to slow the kiln down for a few hours. This could be a disastrous firing....

Levi and I reached cone 10 in the front of the kiln rather quickly, and I decided to drop in temperature and hold it, then slowly bring it back to where we were in temperature, hoping to build up some more ash on the pots. We stoked less wood and allowed the kiln to cool a bit after each stoke, maintaining a temperature for 30 minutes, then climbing 50 degrees and maintaining that temperature for 30 minutes. I had a container of ash I had collected from the kiln's chimney and spread some on a board and knocked it off into the fire box several times.

Then we fired off the kiln with heavy stokes for an hour or so, reaching cone 10 in the back and dropping cone 14 in the front.

After we sealed up the kiln, I noticed a bowl and mug had fallen together, a shino-glazed bowl and a unglazed mug, so I decided to pull them out. They were white, not red/orange/green like we've been getting.

I wondered if they lost their color because I pulled them out of the kiln and quick cooled them? Hmmmm. What to do? Start stoking again and do a reduction cool? Is everything in the kiln just white with green ash deposits?

I decided to try to see into the kiln with a strong spotlight I have. It was difficult, but I finally spotted a shino-glazed pitcher up front and thought I saw some color. Being totally exhausted from firing all day in the heat, I opted to hope for the best and leave it alone.

But now, I'm wondering if I'll have to refire.

After writing this, I went out again to the kiln and peeked up front. There's color up front, so all may be okay.

A heavy stoke near the end of the firing

Peeking in to try and see some color on pots

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