Category Archives: pottery

8th Wood Firing Photo Record

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.

 

Keeping track of clay

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.

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Now if significant time passes between firings, or just unloading a bisque, I can refer to my pictures to figure out what everything is.

Castable door

I finally got around to doing a job today that I’ve been putting off for months. About a year ago I cast six big blocks to use as the front door for the kiln. They really work great keeping most of the heat from the front of the kiln away from the stokers.

Unfortunately though, I kept putting off casting the final top of the arch. Filling in that final space with smaller bricks was problematic because we kept knocking bricks into the kiln when we stoked.

So this morning I finally bit the bullet and gathered together some scrap wood, bricks, plastic, and cardboard, hauled out some leftover castable mix and cast two arch pieces.

With 75 kilograms of castable mix I got two arch sections and the leftover made a new stoke hole cover.
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Duct tape played a major role in holding the flange section of the form together. Love the stuff.
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Clay Supplier

Today I paid a visit to a clay supplier in in the nearby town of Ureshino. They make a clay body that I am hoping will be suitable for large work in the front of the kiln. I picked up five 17kg pugs to make some tests with.

Two of the six filter presses.
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Cakes fresh out of the press waiting for the pugmill.
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A very small sample of their bagged clay.
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Crushing, mixing, and blunging equipment.
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Piles of Toseki (porcelain) waiting for the stamp mill.
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After getting clay, I dropped by my favorite tea store for a good deal on seasonal tea, and to talk about having one of their certified tea instructors give a presentation during the biannual Workshop in Taku next fall.
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Salvage

Finally getting back to work after a very long hiatus, looking forward to posting to the blog much more. I spent some time this last couple of days repairing a large jar that had fallen over during a firing. It had stuck to the floor in a couple of places and when we pulled it up it took a couple of big chunks out of the pot.
I have been saving some knots from a pine board and the nuts were filled with pitch and very hard. when polished they were actually quite translucent and when oiled they shine really nicely. I never decided what they would be good for but when I saw this hole in the jar I thought one of these might be the perfect way to fix it.
I don’t have a picture of the original hole but this is the hole after I ground it out and created a gallery for the wood knot.

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Here it is lit from the inside.

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And finally with the lacquer in gold treatment.  This is a reddish gold color because it’s not actually gold, but rather a mixture of brass and mica.

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New Paddled Water Jars and Flower Vases

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.

3 boat flasks and one taller crane necked flask
3 boat flasks and one taller crane necked flask
water jars. any marks in the clay need to be pretty over the top, because the glaze covers them over for the most part.
water jars. any marks in the clay need to be pretty over the top, because the glaze covers them over for the most part.
lug and lip detail
lug and lip detail
more jars, a couple with 'nail heads' added, instead of lugs. You sometimes see these on tea cups and food dishes in Karatsu ware.
more jars, a couple with ‘nail heads’ added, instead of lugs. You sometimes see these on tea cups and food dishes in Karatsu ware.

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all together now... The tallest flask is about 28cm tall,dry.
all together now… The tallest flask is about 28cm tall,dry.
Karatsu meets pueblo water jar, with kneeling, bowing tea person receiving tea. This started as a lug and sort of went bananas from there. This could be one of those things where I later slap myself.
Karatsu meets pueblo water jar, with kneeling, bowing tea person receiving tea. This started as a lug and sort of went bananas from there. This could be one of those things where I later slap myself.
Tall necked vase with two pairs of tea people bowing.
Tall necked vase with two pairs of tea people bowing.
Karatsu meets pueblo water jar. sorry for the order here...
Karatsu meets pueblo water jar. sorry for the order here…
Lug detail. I really must have wanted to drink tea that day.
Lug detail. I really must have wanted to drink tea that day.
boat flask with porcelain additions. Here's the big question: Will they pop off upon drying?
boat flask with porcelain additions. Here’s the big question: Will they pop off upon drying?
tall necked flower vase with lugs, (finally some normal ones)
tall necked flower vase with lugs, (finally some normal ones)