Fired with cones 6,7,8 on top and bottom shelves. Pyrometer at middle shelf, didn’t display over 1215C.
Hotter on bottom than top. By cone, looks like cone 9+ on the bottom, cone 9 at the middle, and cone 8+ at the top.
Reduction strong at top shelf, weaker at middle and bottom.
This firing of the kiln went too long, resulting in Orton cone 11 flat. Ideally, it would be cone 11 touching, then sagging a bit.
Upon unloading the kiln this morning, one thing was immediately apparent: the right side was far more reduced than the left. Yellower glazes and more slumping. Even on the left side there was some slumping, because of the excessive temp., and because of the clay which contained some low temp high iron clay to help seal the ware against leakage.
Chosen Karatsu came out pretty good, but the white was on too heavy, running down the pots too much. It still came out looking ok because of the clay.
Most of the teabowls warped or sagged, so I only get to keep 2 or 3 of the 15. This is why teabowls are expensive, kids…
All in all, not a bad firing, but need to adjust clay bodies, and pay closer attention to cones. Also, figure out the over reduction on the right side. It might be that one burner that sounds a bit off.
I’ve gotten pretty far behind keeping up with the blog, falling into the bad habit of making small posts to Facebook. One of my areas of increased effort over the next year will be to work more on maintaining the blog, and getting it more integrated with other forms of social media. Trying to keep track of them all is like trying to herd cats.
I had made one promise to show before/after pictures for a couple of pieces, the first of which is the slab/paddle built sake chiller w/ feet and lugs:
The other thing I’ve been working on since early this year is getting a usable kohiki/clear glaze combination, because for some reason a lot of customers have been requesting white work. They have also been requesting black, so I’ve been working on getting a reliable semi matte black glaze. Mission not quite accomplished, but I feel I’m most of the way there. Here is the kohiki I’ve come up with and I am happy with it:
Here are some of the pieces with the new black glaze. It seems to look best thin, and as with most glazes looks nicer over interesting wild clays rather than processed clays.
I had a gas firing a couple of weeks back which was mostly line blends and other glaze combination tests. More than half of the ware in the kiln was glaze tests. Finally trying to get to the bottom of my Chosen Karatsu glaze woes, which started after my ash source changed. Both of my bread and butter glazes stopped working, and it now seems that I just made a spectacularly bad choice for my replacement ash. I tested 3 different ash types in the load and came up with two types that seem to work pretty well. I will mix up small amounts of both glazes with this new ash and see how they work. If things look good, I can then go ahead and mix up a larger batch.
I made a batch of soba choko as well, to take with me to Tokyo toward the end of this month. I’ll be participating in a small event and needed some small things to take and show.
In prep for the spring firing of the wood kiln, I’ve started making work a little different that I have done before, more playing with rim shapes and putting feet on things. The larger platters are actually inspired by some old Shino and Karatsu pieces of similar shape. Almost everything pictured in this post is porcelain, either pretty white stuff, or ‘dirty’ having been run through my pugmill which contained red stoneware previously. I always hear how porcelain is so difficult to work with, but my experience is the opposite. It seems very forgiving compared to my usual short, large particle clay bodies.
I am making the distinction, because this last trip to Korea and the tea bowl festival really accented the differences between the preferred shape of a tea bowl between cultures.
The one type of bowl here that probably illustrates the point best, but of which I don’t have a good example, are the Ido chawan. We make these forms in Karatsu, but don’t refer to them as Ido Chawan. Rather, we call them Karatsu Ido, or Ido Gata Chawan. The original Ido Chawan are from Korea, and contrary to the idea that the ideal shape is like Kizaemon (below), Ido come in many shapes and sizes. I’ve even seen on Ido bowl with a warikodai (foot carved into sections).
Anyway, if you look carefully at Ido forms, two things are often noticed: One, the lip is quite sharp on the inside edge, even though the outside of the edge is rounded, and two, the interior of the bowl is not rounded but rather pointed. These characteristics seem unrelated or even impractical for tea, after all, who wants a lip that is less durable, wouldn’t a round lip be more practical? Also, a cone shaped pointed interior is not suitable for whisking tea, is it? There is no room for the whisk to move, after all.
So why did tea masters choose these bowls as paragons of ‘teabowlness’? The answer is simple. They weren’t used for whisked tea. Most tea practice revolves around usucha, or whisked thin tea, but the tea that holds the highest position in tea ceremony as an indispensible part of Chaji, the full tea ceremony, is koicha, or thick tea. Thick tea is not whisked, it is kneaded and folded slowly into a thick paste with the whisk, and the coned interior of the bowl allows for this to happen much better than a flat or rounded interior. Then when drinking this thick paste, it is much better to have a sharp interior lip in order have a clean separation from the bowl when drinking. Koicha is usually a shared bowl, and will be shared by two or more people. After drinking, you must wipe the lip and pass it along to the next person. The sharper interior lip makes both drinking and wiping an easier less messy experience. So, these two characteristics end up being optimal for tea, in the proper context of Japanese koicha.
Even more interestingly, these two characteristics were not intentionally designed by the makers with koicha in mind. They are the direct result of the clay, process, and tools used to make the bowls, which were likely made quickly in large numbers.
In Karatsu, we use cows tongue ribs to shape the clay, because it is large particle material and not very plastic. In some cases, such as porcelain stone and sandstone, it is not even clay at all. The cows tongue allows shaping by compressing the clay body, rather than stretching, like a standard rib would do. I always thought that cows tongue ribs came from Korea, but I have never seen one there during my visits. There is, however, a tool that looks a little like a mini tugboat that functions much the same way as a cows tongue. When making bowls quickly with as little wasted movement as possible, the interior of the bowl naturally becomes conical rather than rounded, and pressing the lip between finger and cows tongue naturally produces the characteristic Ido lip shape, while preventing splitting of the lip by compressing the un-plastic clay body, and also eliminates the need to use a chamois on the lip to compress or clean up.
So, I seem to have gotten off on a bit of a tangent here, but back to the main goal of simply leaving you with some images of tea bowls:
In a recent massive cleaning around and in the studio, I changed things around to utilize some of the outside space more efficiently. One of the most important things is that I now, again, have a setup for processing clay and ash that I have collected and burned.
I had been getting close to finishing off my stores of collected clay that I processed some years back, time to start doing it again. I think I have a better system this time, and I have an inexhaustible supply of pine ash for now, too.
I have buckets, bags, and jars full of old collected clay and dry trimmings that need recycling. It should take some months to get it all blunged and pugged.
The Choppage ‘cho’ ‘pah’ gay’, is a traditional Korean tool for scooping off clay and other materials without disturbing everything underneath. It works much better than a ladle. I couldn’t find anyone who made them anymore, but my mentor still had one which is kindly letting me borrow.
I just agitate the material in the bottom bucket, wait, and scoop off the stuff that settles last.
Then, later after it settles in the upper bucket, I siphon the water back down into the main bucket. When enough of the upper bucket fills with material, I dump it into cloth lined basket or plaster to get out the excess water.
With the ash, the process is the same, but after I get out the good fine ash I transfer it into another bucket and wash it some more to get out the nasties. The nasties cause problems with glazing sometimes and I don’t like them. I do save the water containing the nasties for other uses.
The leftover rough ash stuff seems like a waste to just throw away, so I am thinking about ball milling it to see if it can be useful in some other way. We’ll see…
The sieve is 120 mesh, because I lucked into a cheap recycled sieve. I would usually use 100 mesh, so it is not much of a difference.