Tag Archives: karatsu

Postfire thoughts

Well, time to sit down with the last firing and figure out what went wrong, and what went right.

Firing and packing: Great. With this firing I figured out, FINALLY, the proper exit flue volume to use. And with it, the proper packing procedure. The kiln climbed steadily, without effort, for 45 hours and the flame in the front chamber reached front to back really nicely. It turned out to be a fairly even gradient from front to back, from cone 13 in front, to a good melted 8 in back. No sidestoking necessary.
I am going to go back to using a pyrometer for the next firing, because this firing got very reduced. I think the stoke intervals were too close, and a pyrometer may help me get a better idea of temp climb timing, and when each cycle goes into oxidation.
At one point, when we switched to stoking the 2nd chamber, the temp just started dropping. You could tell from the sound and color of the kiln. I jabbed a pyro into a peep hole and it told me right away that I was stoking to frequently. After the flame had receded into the chimney and peepholes, and the roar had died away was when the temp really started climbing in the chamber. I had been stoking when the flames receded and the kiln quieted down, but once I started waiting rather for the temp to start dropping after the rise, the kiln got back on track. This rise took longer than I imagined, sometimes up to 10 minutes. Had been stoking waaayyyyyy too much.
This firing was a watershed moment for me, regarding packing, air, and stoking. I think next time will finally be the load that makes us all smile.

Glazes: Glazed ware in the second chamber turned out really nice. Reduction was still too heavy, but we got nice surfaces. Still, I won’t aim for that in the future. Madara glazes were too yellow for my taste. The first chamber glazes were so reduced that whatever their intended color, everything turned out a semi matte green, from the excessive iron pulled from the body saturating the glaze and crystallizing. I think the stoking interval will fix this problem.

Clay body: Oops. Here is where the shit hit the fan. Too much iron, especially considering the temp and amount of reduction that happened. The clay I used for the large pieces has too much iron for that type of firing environment, which is why they almost all collapsed. Having worked with a gas kiln for so long, it is hard to get out of the mindset of adding iron rich clay to other whiter bodies in order to get a desired color. The white clays in this area have enough iron for good color in a wood kiln. I keep forgetting that, but perhaps the shock of this latest meltdown, and the subsequent pain of shelf grinding will serve to jog my memory whenever I’m mixing clay for the wood kiln.

We got this off the shelf in one piece! The attached cup sits level when you set the piece on a table, so great for sashimi and  sauce or condiments.
We got this off the shelf in one piece! The attached cup sits level when you set the piece on a table, so great for sashimi and sauce or condiments.
The Fall of Icarus
The Fall of Icarus
Arm detail
Arm detail

Spring Firing Results

Ok, lots of things to say about this last firing, but with the studio show starting tomorrow I just don’t have time for a long post. Here are pictures instead, commentary and contemplation about these results will follow in a few days…

A few things…

Well, last weekend’s firing is now unloaded and most everything turned out well. It was all for a wedding, so always good not to have to do it all over again…

Before and after pictures:

Loaded and ready to go...
Loaded and ready to go…
Finished katakuchi, about 25cm wide.
Finished katakuchi, about 25cm wide.
interior detail
interior detail

Next are some teabowls for the next wood firing. Made from some really gnarly clay, I had high hopes for trimming these…..until I forgot about them and they dried out too much to trim! Dag’nabit!

teabowls
teabowls
Guinomi
Guinomi

Have a great week!

Testing new WP functionality

*Testing new blog to FB forwarding app* *New gallery image display format*

 

At long last…

… some pictures of new fired/finished work. Finally got my brightness and white balance issues resolved and took a few pictures to share with everyone.

I hope you enjoy them…

Going with the flow

The last slab of the bunch is the biggest at about 10kg/25lbs. I wanted an ocean motif and started out with ideas for iron brush decoration of waves and ocean birds, with a clear feldspar glaze. Somewhere along the way it changed into two opposing wave patterns, one stamped and the other carved.

The pattern is identical, but the exterior wave pattern was made with my paddle, carved with a wave pattern and used like a bench chisel, placing it on the clay and tapping it with a mallet to create a repeating pattern. The center wave pattern is the same as what is carved into the paddle, but varies more because it follows the changing width of the center swath.

If I can get this one to dry without cracking, it should take the firing ok. It will be glazed in either a white ash glaze or a green ash glaze. A nice runny ash glaze should fill in the texture and accentuate the pattern nicely.

tabula rasa. I haven't decided what to do with this yet. It is double the size of the others, 10kg of clay.
tabula rasa. I haven’t decided what to do with this yet. It is double the size of the others, 10kg of clay.
stamped pattern finished, pattern for carving drawn in.
stamped pattern finished, pattern for carving drawn in.
Carving finished
Carving finished
detail
detail
Edge treatment finished
Edge treatment finished
Detail
Detail
detail
detail