So, WHAT'S Katie up to???

Thursday, September 9, 2010

Studio #8

So..... All my artistic efforts over the past two+ weeks are reduced to this..... a couple of boxes of dusty, nondescript little square-ish bits. Looks less than impressive when viewed like this. But, there is gold in those boxes I hope! After a few hours out in the sun to get nice & toasty warm & thoroughly dry (just in case, since cave studios can be a little damp), the tiles are loaded into the kiln.

The kiln is a home-made affair: there are no pottery supply shops here where one can go and order a shiny new kiln. Virtually all the kilns in Avanos, of any sort, are made right on the spot. This one is electric, with a nice digital temp gauge. Erdogan's previous kiln was wood fired, requiring overnight babysitting to feed the fire, and also needing an experienced eye to assess the colour of the red hot pieces to tell when the firing was done. When I first came here 10 years ago, the kiln was oil-fired, and very stinky. The electric one is head & shoulders above both of the earlier ones. Propane is available here, but it is very pricey. There is even natural gas in some parts of town. But most kilns are still electric, since most potters here don't need the oxygen reduction capabilities of a gas kiln, and electricity is actually quite inexpensive (though you can't convince the locals of that....).

You can see by the photo that there are no shelves in the kiln. Pieces are piled on the kiln floor. Depending on the size of the various pieces, often the whole interior is full. But, when firing tiles like these, there is a limit to how many one can stack atop one another. So, a 'load' doesn't take up much space. The temperature sensor is near the top, near the back of the interior -- the hottest spot in the kiln. Not so great, especially when the space is 2/3 empty. I have suggested many times that using shelves would make firings more efficient, even, and predictable. But, shelves are expensive, shelf props take up space, and they've been doing it this way for hundreds of years... so, they nod politely, acknowledge the brilliance of my suggestion, and continue to fire in the usual way. It works for them.

The photo above shows the kiln fully loaded and ready for firing. Notice the colour of the clay before,

and after, the 12-hour firing. This firing was to 850 degrees C -- about 150 less than my usual bisque temp.
But the clay fires to a wonderfully warm terracotta colour. It was exactly right.

So...... if it was exactly right, where the heck are all the nice oxide colours I was supposed to get? The line-mark-textured parts were supposed to be a nice soft green. And the black parts with the little dimples were supposed to be a sort of teal colour. At least, that's what I get in my kiln at home. So, what's up? I confess I was a little disappointed.

As usual, it all comes down to science. First, the temp was a lot lower than I'm used to. In fact, a couple of pieces that were at the back of the kiln in the midst of the pile, where it was nice & hot, actually showed a bluish tinge to the black parts. But they were still more black than blue. Then I noticed that a couple of tiles that I'd brushed white slip onto before applying the stain had indeed fired blue. & the lightbulb went on. Of course! My usual clay has virtually no iron in it. It fires white at 1000 degrees, and sort of creamy at 1250. So, of course there's nothing to interfere with the colourant, and I get my usual results. & I now understand why Erdogan mixes his colourants in white slip before applying them to the clay. They are still altered somewhat by the colour of the underlying red clay, but the colours are reasonably true and predictable. A valuable lesson for me, and all in the process of understanding one's materials. Different materials require different treatment at all stages of working. & I'm still learning about this Avanos clay.

I have found a pretty exciting solution to the colour issues from the firing (you'll have to wait to see the photos of the finished pieces...), and I have put my lesson to work for me in the remaining panels I'm doing.

In yesterday/today's panel, "The Yellow Kite", I've used both my usual oxide solutions and some of Erdogan's coloured slip. The panel is loosely based on a wonderful photo (we call it "Kite Girl") that André took and sent to me from Peru. I knew right away that there was a panel in there somewhere.

All for today.

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