Here are some of the first pots to get cleaned up after the firing last week. I’ll post more over the next few days as I get things cleaned up.
Overall the firing went well, much better than the first two certainly. I’m finally starting to get a grip on how the kiln climbs, and learning not to worry about it too much. We fired both chambers this time and it took roughly 30 hours. Cone 10 flat in front, cone 9 touching in the rear, and cone 13 almost touching in the second chamber. The second chamber is a pleasure to fire, very relaxing after stoking the front. I think I can still get more aggressive with the front, taking the temp up even more, probably somewhere around cone 12 would be good for the rice straw ash glazes.
The intention was to drop cone 6 in the rear and call it quits, but it ended up getting hotter than expected, and the ware in front ended up a little too shiny. However, the middle and rear of the setting came out just about perfectly. Temp from top to bottom was quite even. We stopped stoking the second chamber when cone 11 dropped and clammed everything up after letting some of the excess heat out. Still, when I peeked in the next morning, that second chamber was still glowing, and cone 13 was mostly down. Guess that 1250kg of insulating castable does its job well.
Most of the failures this time around were caused by bad glazing, not the firing. Rice straw ash glazes were universally too thick, and an ash glaze I whipped up hoping to be a nice runny green ended up being a crusty reddish brown. Oops.
Finally! After seemingly endless days of loading, the front is finished. The large pieces in front are most refires with the exception of the large jar to the right. The big white piece in the middle isn’t a pot, it is a large piece of Shirakawa Toseki (porcelain stone from the Shirakawa area near Arita dam). The square right behind it is a piece of sandstone that I cut in two and hollowed out to make a box.
On and off I’ve had requests for pictures of the kiln, so here are some selected photos of it from beginning to completion. Building this kiln was the subject of the first Workshop In Taku, in 2010. The second in the series, Workshop in Taku 2012: The Simple Teabowl, will happen from May 12 – 18, 2012. Full details here:
The series starts not with ‘the kiln’, but ‘the hole’.
Kiln design and expert workshop guidance by Craig Edwards of Minnesota.
The date for the fall firing is official! 2011/11/11. There must be some sort of astrological significance to this, be it good or bad.
Since I’ve been making a lot or work to go into the kiln for this firing, I’ve been constantly short on ware boards, so decided the best way to free some up would be to get the pots off of them by loading them into the kiln. This has the added benefit of breaking up the loading process so it is not so danged exhausting.
This afternoon saw the completion of the rear setting, all cone 6 ware give or take. E-Karatsu, Kawakujira, and Kohiki. Most everything is smaller and doesn’t have much height, so to fill in the higher spaces many of the pots were balanced on kiln posts. The added benefit to this is that if the temperature gets too high, the pots will collapse, invert around the posts and stick to them completely and utterly. Post-In-A-Cup.
The two jars are refires that had a lot of unmelted ash on the shoulders. In order to melt it, I’ve applied an ash glaze that should melt and flux the sintered ash underneath, hopefully. And, if I’m really lucky, they will slump or split in the firing, sticking to everything around them.
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)
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.