Tag Archives: karatsupots

Making pots again

Started making pots for the wood kiln today, after spending some time making a list of what needed making, and working on some sketches and sizing.

These are the beginning of the first items on the list, I wanted to get more done but spent much of the day cleaning up the studio after the gas kiln unloading. This is a very typical Karatsu shape, and you see them from very small all the way up to very large. These are 19cm and 16cm sizes.  As you can see from the pictures most of these plates will probably get brush deco and feldspar glaze (cone 6, give or take), some others will get rice straw ash glaze (cone 11, give or take)

Here comes the flood

Not!

The concrete combined with the sump pump is doing its job admirably. I took these pictures this morning after a night of med/heavy rain (but nothing close to the storm last evening). Water has started to seep in places, and since the part in the foreground is not under cover, some rain falls right in, but that will only be a problem during firing.  Last firing there was some rain and I strung a tarp down at an angle from the cover which worked alright, if not very elegant.

Here are the pictures of everything when it is moderately wet. Water is collecting around the edges of the concrete, but even in the heavy rain yesterday, was unable to reach the top. The sump pump has activated at least once, judging from the wetness of the concrete in the sump. When the top float goes up the pump turns on, and when the bottom float goes down, the pump turns off. It takes about 25 seconds to pump the water out, MUCH faster than the previous pond pump. The sump form collapsed under the weight of the concrete so is not the oval I had planned, but looking at this pic now, the sump really resembles a fish, don’t you think. Especially with the corrugated edges where the tail would be.

I installed a tube into the concrete through which to run the pump hose and power line, so it would be hidden. There is a drain about one meter to the right of where the hose and line emerge. Once a trough is dug between the two, the hose will be almost hidden.  A trough will also prevent water from traveling along the surface toward the workshop path and kiln.

The unfortunate casualties of all this improvement are the frogs, and I am going to miss them. Hopefully they will find other low wet areas in the yard to hang out.

Non saggar stuff

Some other things from the last firing included teabowls, sign post caps, katakuchi, and a lot of hammer fodder. Been having problems with my Chosen karatsu lately, the ame-yu is not playing nicely like it should, and this firing for the first time ever, I ended up with pinholing in my regular madara-yu. This is usually a very dependable glaze for me so I am kind of mystified and perplexed. The only difference from the usual was the clay, so I’ll start diagnosing the problem from there.

Shell geekery for shell geeks

Warning! Geek alert!

Today on the way back from teaching, I stopped by the seaside shell pile to collect some cockle shells for firing. Though I usually don’t find “the good ones”, today I got lucky. Pictured below are the two types in the area. The thin type with the many, shallow grooves comprises about 99% of what one can find, so I usually use those, but today I found quite a few of the deeply grooved bumpy, thick shells. These are better for standing pots on because they are thicker and don’t collapse in the firing, so they don’t need to be stuffed with fire clay, at least for small to medium sized items. They also leave a more interesting mark on the pot.

“Hi, I’m Mike and I’m a shell wadding geek.”

“Hi Mike” (SWG Anonymous group murmurs)

Gas kiln with saggars

People sometimes lament the limited effects possible in gas and electric kilns compared to wood kilns, but there are ways to get many interesting effects in gas and electric if you use your imagination and do some experimentation.

This time around I loaded about half of the kiln with saggared ware. 4 incense burners, 3 sake cup refires, 2 boxes, 2 teabowls, and 1 frog toilet (in porcelain, no less).

The incense burners came out most interesting, with a lot of deformation occurring in the clay, which was the goal. Nakayama kun wanted some burner bodies that were deformed and all around ‘grungy’ to fit with silver lids. They were wrapped in rice straw rope that had been soaked in a saturated solution of soda ash, mixed with some feldspar, the idea being to get some focused area effects on the pot surfaces. The soda ate into the clay in places and fluxed the feldspar nicely. One of the burners completely collapsed and stuck to the saggar and the adjacent burner, but I’ll be able to keep 2 out of the 3.

Two of the teabowls, with iron based glazes turned out nicely, but one (the black one) stuck to the saggar and will need some repair on the lip. Nakayama kun is going to do a silver repair on the lip, and I’ll post a picture when it is done. The other, and iron saturate glazed bowl, turned out nicely but I really can’t decide if I like the glaze color or not. Need to whip up some tea in it to see if it shows off the tea color well or not.

The porcelain ring boxes were a complete failure, with cooling fractures I think. I drizzled in a soda/spar slurry on the insides and it was waaay too thick. I think its expansion and/or contraction fractured the pots.

It’s Official

The kiln is finished. Yep, you heard right. Done. I can hardly believe it myself.

Cleaning up the front area and getting the concrete in was the last job, and it is done. Now, working on the kiln will consist of playing with the flue dimensions and firing it, something I am looking forward to, and have started getting work ready for the  upcoming October firing.

I pulled the forms off this morning and cleaned up the concrete. The sump form had collapsed under the weight of the concrete, so I didn’t get the nice oval I was aiming for, and I had to go in with a hammer drill and concrete bit to clean out some of the concrete that had encroached into the sump area. It was still not quite cured, so not too difficult to break up.

Though I imagine water will still rise in the mouth of the kiln, it won’t be dirty runoff, and the walls of the stoking area will not be eroding every time we get rain. Once I get my hands on an automatic sump pump, I’ll be able to cover the sump and forget about it. Yay!

Actually, looking at the front area again, if we could think of a way to create a waterproof wall across the front of the kiln, we could have the first kiln heated jacuzzi. In fact, we could probably ‘soak and stoke’, relaxing in the hot tub while simultaneously firing the kiln to cone 13.