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More refired pieces

Here are more of the refired pieces, some of which turned out nice. Those of course are the only ones I’ll be showing here. The others are already resting peacefully on the shard pile, and we mustn’t mention them here on the blog….

This katakuchi was my favorite of the bunch, just because of that interior. I don’t think the photo does justice to the colors there. This coloration is really hard to get in gas, and it came through in varying degrees on most everything close to the flame in the wood kiln. I think it is just that extra sprinkling of wood ash that gets deposited on the surface. I don’t know what it was that created the gold speckles.
One thing I’ve noticed is that the rice straw ash glaze can go on thicker in the wood kiln, and you don’t need to worry about a boring expanse of white on the ware, because of all the fluxes flying around in the kiln.

Here are some larger bowls that came through ok. One has some green Oribe on the lip that slid down pretty far, and has some nice color. The others are the same glaze as the katakuchi above, which is wood ash, rice straw ash, and amakusa porcelain stone.

Comparing Pieces

Having just finished a refiring of work in the gas kiln, this is a good opportunity to compare work slightly under fired in the wood kiln, to work refired in gas.  Below are two bowls that were next to each other in the wood kiln and didn’t quite get to temperature. The second one I just refired in gas to within about 40 degrees celcius of its regular maturing temperature. The glazes have really improved, in fact are better, in my opinion than just having been fired in gas, because much of the ‘good stuff’ acquired in the wood kiln hasn’t been lost from the glaze surface. One big change, not so good, is the loss of the color in the clay that resulted from refiring in gas. Still a bit better than just having been fired in gas, but very close to the dead colors that gas usually gives.

  
 

I think that if the piece matures properly in the wood kiln, the results would be really nice. The good color response in the clay, with the matured glaze and all of the nuances that the fly ash and gases add to the surface.

A couple of pots

Here are a couple of pots from the first firing of the wood kiln. The first is one of the katakuchi that was glazed with madara (rice straw ash glaze). It went at the rear of the front stack on the first tier above the floor, just forward of the second pair of stoke holes. You can see that the glaze did not melt, or only partially melted, but the interior and foot are really nice because it got buried in the built up embers from the second stoke hole. I tested it out and the clay is actually vitrified, no leaks when I left water in it for about 8 hours. I like the red colors that came out in the interior, and that little nail that embedded itself in the glaze. The only wood that had those little nails was the lath we used to hold the arch forms together, I had thought that I pulled all the nails, but it looks like I missed one anyway. Most of the pots that had really nice color response on the feet were the ones that got buried in embers.

Next is this Chosen Karatsu Katakuchi that was fired in gas and refired in the wood kiln. What a huge difference. The iron at the lip has a much more varied color response, and blues are much more apparent. Also much of the gloss has been lost, and there is much more texture in the glaze surface than before. One thing that is nice: this particular madara glaze pinholes horribly in the gas kiln, especially on the interiors of pots. While this refire still shows some of the original pinholes, many of them did partially heal over, and the other pieces in the kiln with this glaze that were fired for the first time had no pinholes. This madara glaze is the same one that is on the katakuchi above, the only difference is the melt.

One thing I’ve never gotten before are these partially healed cracks in the glaze. Got them in a few pieces, not just refires. I wonder what the cause is?

Empty kiln looking lonely

Unloaded everything yesterday and am in the process of cleaning up. Nothing was over fired, which is not so good. Lots of under fired stuff, some of which is getting refired in the gas kiln today. From the standpoint of a first firing, everything was a huge success, because every decision I made was reflected in the results coming out of the kiln, whether or not the pots looked great. I certainly know where I went wrong, and made some interesting discoveries. Things to repeat next time, and things to avoid.

 Cones pictured are 9,10,11,12, and 13

 Actually got this katakuchi out of the bowl with minimum damage to either.

 Just the rear stack left to unload.

Rear stack cones. 9 and 10 flat, with 11 about 30% over.

One of the biggest lessons I learned (yet again) is not to pay much attention to the thermocouples. We stoked the kiln for a good 10 hours with very little rise in temp in the front/middle of the first chamber. I was getting very frustrated, and the TC read 1130C at it’s highest. Finally, I remembered that I’d put in cones. The top cone pack in front showed 9 and 10 flat, and 12 about half over. So that puts the real temp/heat work at around 1320C give or take. Just  a bit of a difference from the TC!

Main thing to take into the next firing: fire for more than 2 days, even for glazes, but especially for the unglazed work, and bury as much as possible in embers, even the glazed work.

The Firing

Well, the kiln firing happened and that sucker just ’bout kicked my butt. What a different experience from firing gas and electric. Here are just a couple of things I learned from firing the wood kiln:

1. Kilns are very hot.
2. When you open the doors and hole covers the heat comes out.
3. I look kind of funny with half of my eyebrows gone.

The whole firing went off pretty well considering. We only had one bit of drama, and that was when the front stoke hole cover dropped off just as Tsuruta san had finished stoking. The castable cover fell out of the metal frame and flames were shooting out and up from the front of the kiln, which is not a desirable situation. After an initial moment of panic, we covered the front hole with fiber and managed to get the castable back in its frame, and tightened everything up again. It only took us about 5 minutes, and lasted the rest of the firing.

Without going into great detail, here are some pictures:

Up to about 900C there was very little smoke

 Mike stoking

 Mike stoking Daniels work shorts

 Mike stoking Carmens work jeans

 Mike stoking Craigs work gloves

 Tsuruta san checking the temps

 Pretty peep holes

Stoking the clothing was, I thought, a good christening for the new kiln. I tossed in my holy gloves as well, we’ll see just what effect jeans, shorts, and 2 pair of holy gloves had after the kiln cools enough to unload.

More pictures, from the front stoke hole:

 This last one is a bit difficult to tell, but it is the fiber covered 2nd chamber glowing in the dark after we shut everything up and the sun went down.

Now just looking forward to unloading the kiln, which will probably be Wed or Thurs. From initial peeks, it does look like there are some over fired and under fired areas, but that is not unexpected, especially this first time.