Today is the first load of bisque aimed at the fall firing of the wood kiln. About 28 ware boards worth of pots, I really tried to get as much packed in as possible, to maximize the gas used.
I don’t pack glaze firings very tight because I want the calories getting around to everything, but for bisque I’m not too picky.
700C – 750C is my usual peak temp, I like the ware to be very absorbent for glazing, however the resulting ware is quite fragile and needs careful handling.
This time around there are quite a few slab plates of various shapes and sizes, which I am a bit worried will crack. These are stacked on spacers, then more spacers between stacked plates, because I don’t want to take any chances with cracking. The rest of everything is pretty safe, so packed and stacked without too much thought other than to get as much in as possible.
This is the teabowl that fell into the firebox during the last firing and broke into about 12 pieces. After falling and breaking, the firing continued, and the larger shards warped a bit, making it hard to get the pieces to fit just right.
Everything went back together, but some of the spaces were 1mm wide or more, and a lot of filling was required. Not only that, but the edges of the larger pieces didn’t meet evenly, making a lot of uneven fill lines. I thought about grinding down the higher edges, but in the end decided against that, because the fill lines were already so wide in some places.
So, here is the finished piece, with the lacquer and gold brushed on over the fill lines. A pro could have made thinner, more even lines probably, but it was good practice for me. A few more days to dry completely, then it will be time to whip up some tea…
This post is a photo record with comments, in order to organize and retain my thoughts and observations about the 8th firing of the wood kiln. I always think I’ll remember until the next firing, but never do. So, if you get into this, beware there are a LOT of pictures, some of which may seem redundant. There are examples of most of the pots from the firing, minus teabowls and some others which are not photographed yet.
The 8th firing was a charm overall, with many good pots, some bad, and some that will get refired. Kiln was fired in oxidation primarily. We stoked once every 30 minutes for 2 1/2 days, then once every 20 minutes the last half day.
– Front was nicely melted, nice even gradient to the rear of first chamber, E-Karatsu was about ideal. Cone 12 at hottest front down to cone 6 at coolest rear.
– Front chamber behaves like anagama. No significant temp gradient from front to back of each setting. Next firing, will pack kiln by eliminating the space between settings, leaving horizontal space for flame travel. One long setting from front to back of first chamber.
– Ame yu better at low temps. Load rear to mid chamber.
– Ao yu needs more heat, mid to front chamber.
– Large platters go midway to back of front chamber. Too much ash up front.
– Firebox wares are very nice in a three day firing. Great place for Shino, under cover to avoid ash in pots.
– Rear chamber fires fast when preheated for 3 days. Jumped from 1044C to 1344C in four stokes, a little over an hour. Care must be taken to spend more time soaking at high temp, because rear chamber high temp wares not quite mature (surface changes only), clay not melted well. Spend 3 or 4 hours firing off rear chamber, slowly, to get inside the pots.
– Rear chamber fires very evenly front to back, and top to bottom. Pick a temp to fire at and load accordingly. Don’t expect a significant gradient.
As I may have mentioned before, buying the pugger/mixer was probably the best decision I made last year. It has made my life easier in so many ways. However, it has made things more difficult in one way: it is hard to keep track of all the claybodies that go into the kiln. Especially after they are made into something and drying on the shelves, it is very difficult to tell them apart.
When I fired with the gas kiln, stuff didn’t pile up all that much, because I fired frequently. Now with the wood kiln getting fired 3 times per year, things tend to stack up, and labeling is essential to avoid hideous mishaps. I try to keep types of clay consistent from wareboard to wareboard and label each board, but packing pots in the kiln to bisque them means losing the labels and taking extensive notes, because bisqued clay looks even more similar than green.
The other day, I was wishing I had a way to label the pots better, then it came to me: a labeling app on my smart phone with which to label photos in my gallery. I downloaded a free app (there are lots of different ones), and viola!, pictures taken of my bisque load shelf levels are now accurately labeled and instantly backed up to my home network, so I know I won’t lose them.
Now if significant time passes between firings, or just unloading a bisque, I can refer to my pictures to figure out what everything is.
Here are the first of a bunch of water jars and flower vases that are going into the kiln this early fall. I really needed some practice coiling, paddling, and collaring in necks on the kickwheel and 船徳利 funadokkuri (boat flasks) are the perfect shape for it. Traditionally these were used as flasks for oil, etc. on boats. They needed to be hard to tip over, hence the wide flat bottom. Now they are mostly used for flower arrangements.
All of the water jars will have wooden lids made for them. I’ve done one or two in the past with surprising positive response from viewers/customers. The lids are fun to make, since they are a non traditional item, you can play around a bit with them. I’ll post some lids later on, if the pots make it through the firing.