When I was polishing work from the fall firing yesterday, I noticed two pieces that had been glazed, fired (on shells)glazed again, and fired again (on shells). This isn’t too unusual, but in the case of these two pieces, they were literally fired side by side both times and had the same glazes applied, twice.
The only difference between the pieces is the clay body. The teabowl is clay/sandstone 50/50, and the smaller cup is clay/sandstone 10/90.
Now probably it shouldn’t, but the difference in the fired glaze surface astounds me. And all other things being equal, it must be that 40% difference in clay content that has changed that glaze.
Since the glaze is collected, I don’t have an analysis, but my guess is that the higher alumina content in the higher clay body is responsible for making that high silica glaze go clear, by adding alumina to the glaze matrix and fluxing more of the silica.
The first abalone dish dried successfully, so today I started making more. I also started a small run of shiboridashi teapots. These are always good sellers, because they are easy to use and clean, with no hard to reach holes or metal sieves to collect grime.
I always carve the grooves as early as possible, because as the clay gets harder, it becomes difficult to carve without tear out. Then I put the lids on, so that they dry evenly without warping, and after trimming they will go into the kiln to be fired together, to avoid any warping.
This abalone shell sat under a bush next to the pool at my grandparents house for as long as I can remember. My grandfather used to take abalone off the California coast, they were so plentiful you could pry them off the boulders at low tide. This was back decades ago before they were scarce.
After my grandparents passed, I took this shell as a reminder of family, fun times, and good food.
As it turns out, it was perfect for making a plaster mold for abalone dishes. This is just the first, many more to come.
I started playing with soft slabs this week (no not that, you with the dirty mind) and made some paddled forms for sweets and food. They will go into the fall kiln once they are glazed. Here is a finished piece:
They are really simple to make, just cut a slab like a piece of cloth for a sewing project, paddle it to compress and add texture, and fold up/ join the edges. Like this:
Because they are compressed by paddling, and maybe because of the way they are assembled, there are no problems with warping when they dry, which is a very big plus.
Loading of the first chamber began this morning.
The stack starts at the bottom from back to front. This part of the firing process is very important because it determines where the fire and heat will go during the firing. A bad stack means you will have poor circulation and you’ve doomed the firing even before you’ve lit the fire.
The bottom of the stack is pretty much done, and the ware from 9 ware boards got stacked in there, which is about 80 pots give or take a few.
Here is my latest pot porn for you: freshly stamp milled, slaked, and filter pressed cakes of Izumiyama porcelain. 150kg.
Not for the faint of heart, Izumiyama is hard to work with. It is non plastic and likes to crack during drying, impossible for slab work, and deforms easily. And it costs more than twice as much as Amakusa porcelain from Kumamoto. Most porcelain artists in Arita and Imari switched to using Amakusa porcelain long ago because it’s much easier to work with, doesn’t crack, and fires whiter.
BUT! The beauty of Izumiyama in the wood kiln is absolutely undeniable. It fires to a soft ivory white and blushes in very subtle shades of peach. The surface is deep and translucent and vitrifies as low as around 1230C.
Tomorrow morning first thing, Peter the Pugger will be getting a major workout!