Here is my latest pot porn for you: freshly stamp milled, slaked, and filter pressed cakes of Izumiyama porcelain. 150kg.
Not for the faint of heart, Izumiyama is hard to work with. It is non plastic and likes to crack during drying, impossible for slab work, and deforms easily. And it costs more than twice as much as Amakusa porcelain from Kumamoto. Most porcelain artists in Arita and Imari switched to using Amakusa porcelain long ago because it’s much easier to work with, doesn’t crack, and fires whiter.
BUT! The beauty of Izumiyama in the wood kiln is absolutely undeniable. It fires to a soft ivory white and blushes in very subtle shades of peach. The surface is deep and translucent and vitrifies as low as around 1230C.
Tomorrow morning first thing, Peter the Pugger will be getting a major workout!
There is an old story around here about Nakazato Muan (12th Generation Nakazato Tarouemon, Living National Treasure) finding a really great white clay seam in the Azambaru area of Taku. Here it is in Japanese for those of you who can read it:
For those of you whose Japanese is a bit rusty, it goes like this:
In the year Showa 21 (1946), the Nakazato kiln was converted from a coal burning kiln to a wood burning kiln, and it was fired until Showa 25 (1950). During this time, Muan mostly used a white clay from the Azanbaru area of Taku. There is a story, told by his son Shigetoshi, from the day they discovered this clay seam (Nakazato Shigetoshi passed away in 2015, at the age of 85, so he was probably around 16 years old at the time of this story).
So they have all this clay loaded onto a cart, which Shigetoshi is pulling and his father Muan is pushing, to Taku train station.
On the way, they reach a downward slope, and without noticing, Muan keeps pushing down the slope, and they almost run into a car speeding down the road. Shigetoshi ends up diving to avoid the car, the car ends up in a rice field, and their cart ends up broken. When Shigetoshi gets angry and starts yelling, Muan says “I was so busy thinking about what I was going to make with this clay, I didn’t notice the slope.”, apologizing to Shigetoshi.
“That was the first time my father ever apologized to me.”, Shigetoshi commented.
So why, you say, are you telling me all of this? Well, the fabled white clay seam has been looked for now by other potters for decades with no luck, but due to a fortuitous event a few months ago (and several years of looking), I believe I have found it again. Here are some pictures from our excursion out to dig some sample material for testing.
Oh, and lastly, here’s a picture of one of Nakazato Muan’s coil and paddle built jars. This one is made from white clay from the clay seam pictured above. My firing tests have almost the same color as the unglazed bottom section of this jar (although it is hard to see from this dark picture).
Getting ready to set up a whole kiln load of glaze tests to fix my misbehaving ame (iron/ash) glaze, and realize that I’m out one very important ingredient, red ochre collected from a place right here in Taku. Completely forgot that I had used the last of it in my last glaze batch mixed up a couple months ago. Doh!
So…. Delay the mixing of test glazes for tiles and cups, I had to spend the day crushing and sieving red ochre. I haven’t used my man powered stamp mill in a while, and I added too much material to the mortar. My wooden pestle (4 foot long pole) that I use to stamp the material was just not up to the task because it was too light to sink down into the material and get it circulating in the mortar. To remedy this, I retrofitted one of my wooden pestles with some 3cm diameter round steel bar left over from a long piece of bar I cut into sections for my kiln’s grate bars.
This new pestle worked really great, so great in fact, that material was flying out of the mortar from the striking force. So I proceeded to cut down a large cardboard box to keep most of that stuff from flying out or away. It is really hard work digging it, carting it around, and crushing it, I hate to lose any at all.
So anyway, here are some pictures of today’s festivities, and I did wear a dust mask, so I don’t have to worry about getting red lungs…
Lately I’ve been working on ways to bring out the crackle in my teabowls, as well as make the crackle finer (without having to use them for decades or centuries, or reformulate my glazes, so in other words: cheat).
These two bowls had big crackle ( 1cm +-) and I reheated them, then doused in cold water.
***WARNING: Ceramics generally don’t like to be heated or cooled quickly. Don’t do this if you’re going to be upset about breaking a bowl!***
For the kohiki bowl, I heated and doused once to make the crackle smaller, then reheated to open the crackle wider, and closed the damper on my stove, to get that carbon to penetrate the crackle.
Because the body and the glaze were vitrified, but the white slip in between wasn’t, spots (where the slip was thickest) on the rim separated from the body and had to be restored with lacquer and gold (*1)
The results vary, and it is high risk, but you can get an idea about how your bowl may mature over years of use, and plus it’s just fun to play around with fire…
Another common way to bring out the crackle in you ware is to boil it in a pot of strong tea for a few minutes. The tannins will then turn brown, especially if you put the piece out in the sun to dry (or any other UV light). For an even darker, quicker reaction, after the piece is dry, apply some iron acetate. The iron acetate reacts with the tannins and turns quite black over a period of 24 to 48 hours. This is actually an old woodworking technique that I applied to pottery, and it works well, in addition to being non toxic.
***Results may vary***
(*1: I didn’t use real gold for this bowl, but I would on a very nice piece. For this piece I used a brass based metal powder. For more info on this kind of repair, check out Dave Pike’s blog, or store on Etsy)