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).
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?
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. ; )
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….. : )
My apologies if you are getting sick of these water pictures. Whenever it rains and fills up, I for some reason am compelled to take a picture and post it. Some sort of weird compulsion I guess.
Anyway, I had an epiphany after the latest rain (we are into rainy season here now, with a vengeance). Why not use the kiln area as a koi pond when not firing? Not only would it likely be the first kiln in the world to also double as a water feature in the yard, but visitors could also enjoy the koi, and perhaps would even pay for those little packs of koi food, like at the zoo. Genius, no? OK, well, maybe not.
Still here’s that picture I am compelled to post.
With the primary air dampers closed, couldn’t the area under the grates be used as a separate enclosure for raising the fry?
The mud that I ordered came on Monday, and even though the kiln is still warm, I’ve started applying it. Actually, it really helps it harden faster and stay in place. It will crack pretty badly but it would anyway, and I plan to go back later and fill in cracks and joints later anyway. What you see here is one ton of cob, which is composed of unrefined red mountain clay, decomposed granite sand, and straw. I don’t know the proportions, but it shrinks about 3% from wet to dry.
Now that the first ton is used up, I need to order one more, and that should be enough to finish the job, then have leftovers for crack mending and a finishing coat, plus enough to insulate the new pizza oven that we are building from leftover kiln bricks.
While working this morning my twisted mind came up with this, you may be familiar with a slightly different version:
“I held the spade in trembling hands Prepared to slap it on but just then the phone rang I never had the nerve to add the final…. coat. “