This is the diamond fiber pad I’ve been talking about. It’s about 3cm thick and fairly rigid, with just a little bit of spring. The machine is an off brand knife sharpener with the guide and water trough removed. At first I removed the stone and tried to put the fiber pad in its place, but realized it would just be easier to fit the pad over the stone. Much easier for switching back and forth.

I decided I needed something like this after I bought the pad and used it attached to my elec. wheel. Lots of dust in the studio, so I started hauling my wheel outside after every firing, which got old real fast.

They have machines here made specifically for polishing feet and butts which start at just over $700. They are essentially what you see here except with a steel cover, and probably a more powerful motor. The polishing media is the same. I spent about $50 for the sharpener, and about $50 for the fiber pad.

Here are some of the guinomi from the same firing. These are the guinomi you’ve seen in the previous recent posts. The hand dug, hand processed clays came out really wonderfully, interacting with the glazes in ways I had not expected. I had worried a little that they might bloat or sag in the firing, but they handled the heat well. I should not have worried, since the Sari area of Saga where this clay came from is the same area as the oldest Karatsu kilns. Here are a couple of the Sari clay cups glazed in Chosen Garatsu style. The lighter one has some ball clay mixed in to make it more workable. The redder one had some ‘store bought’ Karatsu Red mixed in. Both really turned out to have some nice texture for the glaze to run over. Notice all of the little ‘ishihaze’ where the chunks of silica ruptured the surface of the clay.

Next is a cup glazed in just Madara glaze which is usually white. It reacted very differently over this clay. I suspect the large amount of clay slip (since I threw very soft) I left on the surface after throwing the cups melted together with my ash based Madara glaze to produce a different glaze altogether. I really like this look because it reminds me of the old undecorated Karatsu ware. The clay in this cup is 100% Sari clay, and you can see it in the rough bottom.

Well, the firing is finished and everything’s been ground and polished. I packed the kiln tighter than I’ve ever done before, which turned out to be a mistake. Not enough heat circulation. Much too hot at the top, and my madara glaze went clear. Bottom half of the kiln turned out really nice though, and since that’s where I had most of my sakazuki/guinomi and chawan, everything is right with the world.
It took 18 hours to drop the cones this firing, and it usually takes 14 or 15 hours if I keep things slow and even. When the bottom cones finally went down, the top was way too hot. Since I had mostly thick plates up top, it wasn’t too much of a problem, but I will still have lots of shelf grinding to do. In one case my green oribe glaze ate right through the clay bisquit I had down to protect the shelf.
The chosen garatsu came out really nice for the most part as you can see from the chawan above. The madara came out really mottled (see the round plate above) which is something I’ve been trying to achieve for a long time. The thick, textured plates came out nice, but would have been nicer at about 1/2 to 1 cone lower temp.

Well it seems to be feast or famine with me and this blog. Haven’t posted for months, but it just so happens that now I’ve got a bunch of pictures, so naturally I’m going to post them, whether anyone else is interested or not.

Here are some closeups of the clays used for the cups in the previous post alongside a purely ‘bought’ clay with just some feldspar sand (yuseki) mixed in for texture.

Generally speaking, Seto/Mino clays are quite plastic in comparison with Saga clays. This has resulted in different production methods and tools between the two areas. Just for perspective, I ordered some clay from a company in Shigaraki a few months back that was described as a good clay for Shino and Oribe, very rough and toothy, and lacking plasticity. I got it expecting to have some trouble with it, but it turned out to be absolutely butter smooth and plastic compared to the Karatsu Aka (Karatsu Red Clay)I normally use. It was much more forgiving than I am used to, and I had a great time with it. The Sari clay is the other end of the spectrum, making the Karatsu Aka seem feel like ball clay in comparison. If I applied too much pressure bringing up the wall of even a tiny cup, the whole wall tore away from the hump looking much like an orange peel coming off of an orange, then the torn piece would drop to the wheel head but not before crumbling into several pieces first. Frustrating sometimes, but really fun to work with, and excellent practice.

Here are some photos of some of the guinomi that I made from the clay processed in the previous post. Gendo means ‘original clay dug out of the ground without and stuff added to make it more workable’.

Here are pics of the wet guinomi. The pinker ones are the gendo, and the brownish ones are about 65% gendo with some red karatsu clay and some feldspar chunks mixed in.

Next are the pics of the cups after the feet have been trimmed. You can see the tearing in some of the rims because of the nature of the clay. The trimmed parts came out very nicely torn and textured with the characteristic ‘chirimejiwa’ or crepe wrinkling effect that Karatsu ware often exhibits.

I found a clay seam about 40 min drive from my house in a place called Sari. It has 2 distinct kinds of clay, one in a thick strata which seems to have quite a bit of
iron, and another in a thin seam that seems to have less iron. In fact, in appearance it looks like wet decomposed granite with the spots of white, black, yellow, etc.

The pictures below are of the larger strata of high iron clay. For Karatsu potters finding a good place for your own raw clay is a great thing. It’s really the only way to reproduce the look of the older Karatsu pieces, and a great way to make some very interesting things with a lot of character. In fact it is almost unbelievable how much of a difference a nasty, lumpy, badly processed, unplastic clay makes in the overall ‘feel’ of your work.

Anyway, here are the pictures of the clay as I worked it over, in the next blog entry I’ll show the cups that I made from it. The first are the raw chunks in the bag.

Next is the clay dried and broken up into smaller pieces with a wooden mallet. It needs to be in smaller pieces to go into the usu (mortar)I use to pound it into powder. Big chunks don’t move in the usu, but smaller chunks circulate as you pound, going from the bottom, up the sides, then tumbling back down into the center, to get pounded again.

Next we have the stamper, looking fairly stamped himself. I have to stand there and pound the clay with that long wooden post. It’s good for the arms, shoulders, and heart, or so I tell myself.

After the clay is finished (rough translation: when I’m too pooped out to keep lifting that *&&^%$# post), I scoop it out and put it in a bin where I add a lot of water to it and use a drill mixer to thrash it about, then I let it settle out. I repeat that a few times over the next day or two, then I pour off the excess water and dump the clay into plaster basins for quick drying.

Finally I get to wedge the clay. It’s still very soft at this point so wedging requires very little effort. First I do a rough wedging, then follow with spiral wedging. With this clay the spiral wedging is very difficult because the clay has no plasticity and doesn’t want to be formed into a hump for throwing. Here, the humps I’ve formed are just dry enough to hold their shape on the wheel, no dryer. If you were to grab either of these humps and pull sideways, they wouldn’t bend at all, rather they would just tear apart. When centering and throwing this clay, if you apply very much pressure at all, it just breaks off in your hands. Frustrating at first. With this clay I wasn’t able to make anything much larger than guinomi/yunomi. I’ll make that the subject of the next blog entry.
Have a great day!