Clay/Centipede Storage

In 2010, when we started digging the trench for the wood kiln, we found a seam of clay from about 60cm – 90cm down. This 30cm thick seam stretched as far as we dug, but with varying levels of iron. I ended up keeping a few hundred kilos of the lightest stuff, and it has been taking up space in bags that have been slowly decomposing over the last 3 – 4 years.

Finally, I rallied the gumption to get that big pile of clay moved today. First, I built an enclosure on the edge of the property behind the kiln chimney, then I started shoveling. The bags were so far gone that they just tore apart if I moved them, so there ended up being very little heavy lifting.

I recently came into a big load of boards used by roadside crews to build temporary retaining walls. They are nice sturdy pine boards (2 1/2 inches thick) and are great for all sorts of projects, although they are not all that great looking.

I ended up just pounding in some steel stakes and tying the boards to them. I looked for some little screw-in brackets to go around the rods and onto the wood, but alas this is Taku, and none of the hardware stores had that sort of hardware. This happens often, and my go to solution is almost always the same: stainless steel wire. It is cheap, comes in various thicknesses, and pretty much lasts forever once in place.

Once two sides were finished, I had a place to put clay, but the storage area is not quite finished. I still plan to put in one or two dividers, so that I have 2 or 3 sections for storing different types of clay. Here is what it looks like so far:

The clay that is still in bags came from about 200 meters away, from the farm reservoir. We drain and muck it out once every 2 years, and that is when I discovered the clay seam. It is not very refractory clay, but it makes very nice pots if fired to the proper temp.

During the process of moving all of this clay, I ended up killing 4, count ’em 4, centipedes , ranging from medium to gargantuan. Normally I would let them go, but lately I’ve been getting a lot of them in the workshop, and they have a very nasty bite.

Processing Clay and Ash

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.

Collected clay that has literally been sitting around for years.

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.

Clay washing bucket setup, and scooping tool, called choppage.

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.

After returning water back into the main bucket from the 'good stuff' bucket. — After returning water back into the main bucket from the ‘good stuff’ bucket.

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.

Pine ash bucket setup, main on bottom, fine up top.

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 leftovers after the good stuff is scooped off.

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.

Dumping through sieve which is sitting on the bucket mouth.

Views of a repaired teabowl

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…

Mamonaku Spring 2014 Firing

New Videos

I finally sat down and figured out how to use my video camera and software. For anyone who is interested, here are some videos I posted to youtube.

Karatsu Sake Cups

Sake Cup Trimming Part 1

Sake Cup Trimming Part 2

Karatsu Teabowls

Karatsu Teabowl Trimming

All of these pots were made with clay from the property, discovered right under where we built the kiln. It has a lot of iron, but still takes some heat, and won’t bloat at higher temps. Probably due in part to the fact that it is very open with a lot of sand and other even larger inclusions. Even vitrified, it still sweats because of the openness. With use, the sweating stops, as all the pores fill with minerals from the water and tea tannins, etc…

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.