Category Archives: tools

The Kinky Kiln

Well, I wasn’t expecting this to happen, but the pizza kiln has turned into a fetish kiln, at least for the time being. Actually, budget fetish, since I couldn’t afford a nice black latex wrap…

Here’s what happened: We finally got the end of rainy season, and have been out working in the yard, finishing up various projects. I saw rain in the forecast for the next few days and decided to get the kiln finished and covered. Oh, and also the big pile of cob I have under the double tarp is starting to get stiffer from the sun, in spite of the good covering.

After digging into the pile of cob I found out that only the very top is getting stiffer, but I had started the job and decided to get something accomplished. After laying in the first 30cm or so, everything started to sag and the more I pushed it up, the more it would sag back down. Pretty soft.  Well, I remembered I have a left over roll of plastic used to wrap palettes to keep the stacks from falling apart when the forklift manhandles them. So, I wrapped up the kiln starting with the base and working my way up over the cob. It really worked like a charm, and I was even able to push the material up and have it stay there, because the wrap is under quite a bit of tension. It is not very strong though, so what you see in the pictures is about 7 layers of wrap over the cob. Quite strong in layers.

I expect that the brick will absorb some water from the cob, and the summer heat will help some of that water out of the mix, making it stiff enough to start paddling  in the next few days. If we paddle everything and get it nice and compressed over the course of the next few weeks, the worst of the cracking can be avoided. All that is left after that is to decide whether to leave it a simple dome, or add some sort of decorative motif. Oh, and bake pizza and bread.

Pictures from the latest firing

Below are some pictures from the latest firing (of the gas kiln). There were a few nice pots in the firing, enough to fill in the gaps with the show next week. Lost most of the chawan and guinomi, but got a couple of each that I like.

Chosen Garatsu (the runny white over brown) constantly reminds me that I need more practice. Just when I think I’ve got it down, it shows me just how much I don’t know.

Rain, rain, GO AWAY…. REALLY!

It has been raining cats and dogs since this morning, and we must have gotten about 8 inches in as many hours. Unreal. It is the first time the water has risen in my kiln to a level that would affect pots if they were loaded into the first chamber. In the past it has always stopped short of the front floor but today it was a couple of inches deep in the front floor area.

At least I had good weather yesterday and into early this morning for firing the gas kiln. Turned off the kiln at around 5 am (fired for 18 hours) and when I woke up at 6, it was pouring. Later in the day, I peeked into the kiln when it was still around 700C. Snapped a couple of pictures, with and w/o the flash. The first glance doesn’t look too good. Ame yu was a bit too thin, I think, but won’t know for sure until I open the kiln up completely and have a good look. One thing I am happy about is that the new clay blend I was testing seems to have stayed together nicely, no bad slumping (a little slumping, I like).

Some new teapots

Here are a couple of the shiboridashi teapots from the second firing, cleaned up with their knobs attached. The knobs are solid silver, polished and fumed to give a muted color that matches with the clay nicely. These are pretty small pots, holding about 120ml of water, mainly used for very nice sencha or gyokurocha.  The first knob is a stylized version of a Ganoderma Lucidum fungi, or ‘Reishi’ in Japanese. The second is a realistic rendering of the same. I am personally very happy with how these pots came together. The test will be at the show next month and the big question is: will they sell?










The Final Coat part II

Got two more tons of cob mix delivered yesterday morning and finished up the top coat on the kiln. Lots of mix left over for filling cracks later, and also for finishing up the pizza oven next week.

One thing I was really happy about was not coming across any dead frogs in the cob, like the last load.

As you can see, great care has been taken to keep the front crack free. I’ve been paddling  and burnishing it in a vain effort to keep it smooth.

You would think there is no real practical reason to keep the surface smooth, but the way it was explained to me, this is actually quite important, because during firing when the kiln leaves orbit and begins re-entry into the Ceramisphere, the temperatures and stresses exerted are phenomenal. Any crack or weak spot in the top coat could lead to catastrophic failure in the kiln structure. ; )

The new pizza oven

Today we got to work on the actual oven finally. We did the base a few weeks back and have been waiting for the rain to abate. We started out pretty straight with our chisel split bricks, the top 20% though gets a bit dodgy, but we hammered the keys in and it is standing on its own, if not very pretty. Over what you see here will be a 5″ thick layer of mud and straw, to seal everything up and add some mass to soak up heat.

The cooking surface is hard castable. Under that is hard fire brick, under which is soft insulating castable, under which are empty beer and sake bottles. The base is a mortared brick cylinder filled with a ‘lasagna’ layered matrix of large and small rocks, and concrete. We needed somewhere to get rid of all the rocks that had surfaced in our landscaping projects, and this got rid of  more than half.

A few strips of bamboo make a quick and dirty arch support for the edges.

Not too bad for a few hour’s work. The bricks are all scavenged, and the dome bricks are wedges cut in half. Arch brick for the door. Left over wedge scraps stuffed in at the apex with mud to fill gaps. The same top coat I used for the big wood kiln will work great for this oven. Inside diameter of oven is 70cm, and inside height is about 46cm. Door height is 63% of the inside height.

The advantage of having the big thick mud exterior layer is that later after a few firings, if the brick dome starts to fall in, the mud dome will remain. Not only that, the interior of the oven will actually get bigger….. : )