Droplets of Iron?

Time for some much needed blog catch up. Just unloaded the kiln yesterday and have a little breather time.

This last firing I put some things in saggars with charcoal and fired. Had some very interesting results, including something I’d been aiming for (for a change). Noticed one strange thing: when I polished the rough surfaces with 240 wet sandpaper, I’d get these shiny spots. I thought that water was filling small holes which were created when the sandpaper broke off the surface of tiny bubbles in the glaze. This was actually happening, but when I looked at the surface through a loupe it became apparent that the shiny objects were small droplets of iron which filled the bubbles. I was actually able to remove one by prying it out carefully. Here are some pictures below.


Beautiful foggy mornings

The last few mornings around here have been quiet and blanketed in fog, which doesn’t burn off early, rather lasting until mid morning. This is the view out the back of our house from the balcony. The line of trees is barely visible.

In other news, I just harvested our last bunch of habanero peppers and cut them open to dry. If I’ve just finished a firing, I can often use the last bit of heat in the kiln to dry the peppers out completely. Have to hold my breath when I open the kiln though. Those habanero fumes are killer. Once they’re dry I powder them in my spice mill (if you do this don’t breathe when you open the spice mill, better yet do it outside) and bottle them for future use.

Post Fire

Well, I was a bit over enthusiastic with the glaze thickness, but everything came out pretty well, all things considered. Here are some ‘after’ pics to put the previous post of pre-fire prep into context. First, the rice straw bottoms:

As you can see, many of the senbei are cemented to the cups. This is because of my being a little too liberal with the glaze. If I’d wiped the bottoms, or used more rice straw this wouldn’t have been so bad. Still, since the bottoms are concave it’s usually just the sides that are stuck and most of the senbei comes off pretty easily. The stubborn stuff comes off quickly with the green wheel. Here’s a finished bottom, looking much better.


Next, the kai-kodai, or shell bottomed stuff:


Above, they are perched on the shells, and any drips tend to just fall to the senbei without messing up the foot too much. Below, here are some of the same cups with shells removed, but not yet finished. The shells came off pretty cleanly, and left nice red flashing on the feet.

Here’s the detail of one of the feet, this actually is the same foot as the one pictured green here in a previous post.

One group of cups was glazed a bit differently in a way which allows the glaze to run more. Here’s where the advantage of shells really comes in. The cup in the pic below was placed on rice straw. Firmly cemented to the senbei and a lot of grinding required. (Actually, no grinding required, as it is now fragments in my shard pile.)

Here’s the same type of cup on shells. This cleaned up in a few seconds on the green wheel.

Last are the small plates laid on rice hulls with their corners supported with shells. Not a single plate stuck to a shelf. A rare occurence for me….

Firing Prep

Well, spent the last week glazing and finally loaded the kiln yesterday. I’d bisqued two pretty full loads, so I now have enough for about 3 glaze firings. I glazed it all hoping to do 2 or 3 firings back to back. Now that I spent 4 full days doing nothing but glazing, I’m not sure if it was a wise thing or not to try this…

Anyway, since Karatsu ware is as a rule one quarter to one third naked, and since I fire in a gas kiln for the time being, I try to think of ways to make the naked clay feet and bottoms more interesting.

One way is to fire on shells, that way you get the flashing from the salt in the shells. There is also the added benefit of keeping the pot elevated so that if the glaze runs too much, you don’t end up with footrings cemented to the senbei (the flat fireclay pads) that need to be ground off. With the shells, often just a little grinding gets everything clean. One caveat: Get the remains of the shells off of the feet before they (the shells) absorb too much moisture because they will swell, and for some reason will often remove chunks of the clay body when they do this. When you take them from the kiln the shells are still hard, but if you wait a day or so in a humid climate, you can take the stuff stuck to the pot off with a pointy steel object (pry away from your fingers and palm). Don’t forget to pack the shells with fireclay so that they don’t collapse in firing, sending your pot tumbling into the 3 others next to it, making them best friends forever. This method also has the added benefit of allowing you to level the pot easily.


The other way to get nice bottoms is rice straw. I like this one more, but if you have runny glaze you run the risk of grinding hell. Sometimes its worth risk, the random red flashed stripes on the bottom of the pots are gorgeous.


One less interesting but much easier and quicker way to set pots and prevent plucking is to put them on a little bed of rice husks, but then you get just the inside of the foot with red flashing which looks a bit unnatural. To just prevent plucking, the quick way is to keep some liquid clothing starch on hand. Quick dip the foot in the starch then quick dip in a bed of husks. Just the wet part will pick up the husks (and hang on to them), and you can set the pot right on the shelf or senbei. You can do the same thing with just water, but by the time you get the pot to the shelf most of the husks have fallen off into your other pots and have to picked out, or you end up with little razor sharp spikes in your pot. I once tried to blow them lightly out, forgetting that breath is not all that focused and all those random air currents pick up every other husk within a 30 foot radius and makes them fly into all your already set pots regardless of whether or not they are already covered by shelves or not. Only did that once…


Here I’ve done it with some small flat footless dishes. For small slabs, the husks allow the slab to expand and contract without cracking. For heavy slabs, sand works better. I put shells under each corner just in case they want to lay down.

Kiln’s firing now, hopefully I’ll have some good pictures to post day after tomorrow…

Bonanza!

On the way toa and from my classes on Friday mornings, I always drive by the same place, a hill cut away into terraces for houses that appear to have never been built, I suppose just another project put on ice until the economy recovers. I never actually got out and close to the place, because from the road it looks like orange sandstone and decomposed granite.

Finally out of curiosity yesterday I drove up the access got out and checked it out. Wow! It’s pure clay, in bands from white to red, and lots of it. And you don’t even have to dig, because huge chunks are eroding and falling out. Just pick up the chunks and put them in the bag. I always keep some bags and a shovel in my van for such occasions, so I brought home 2 bags of white, and one each of brown and red for testing.

Sorry for the bad quality of the pictures, they’re from my digital camera. Close up pics coming soon…


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