Sunday, February 17, 2008

Glazing

Today was my first foray into the world of glazing. And after 3 hours in the studio of just glaze glaze glazing away, I am totally and completely exhausted. (No pictures yet, hopefully some pics of my finished pinch pots on Tuesday or Wednesday, when I see them after they've been fired)

My job with the pinch pots was to make use of as many glazes as possible so that I could see the kinds of things they do - also, I guess, to practice glazing on things I don't care very much about. I made a little organized chart in my sketchbook to keep track of everything I did. And as I'm sure you're all curious to know what the chart looks like, here it is:

Pot#Type of ClayGlaze/Technique
1Dillo WhiteOribe (inside); Winiker Blue
2
Dillo White
Tom's Copper Blue (inside); Tumoku
3
Dillo White
Rustile Green (inside); TC White
4
Dillo White
Rutile Blue (THICK inside); Celadon (leaked into inside!)
5
Dillo White
Kaki
6
Dillo White
TX Blue Green
7
Balcones
Kaki
8
Balcones
Oribe (inside); Temoku
9
Balcones
Rustile Green (inside); Winiker Blue
10
Balcones
Tom's Copper Blue (inside); Celadon
11
Balcones
TC White
12
Balcones
Shino
13
Balcones
TX Blue Green
14
Porcelain
Kaki
15
Porcelain
Shino
16
Porcelain
Oribe (inside); Celadon
17
Porcelain
TX Blue Green
18
Porcelain
Tom's Copper Blue (inside); Winiker Blue
19
Porcelain
Rutile Green (inside); Temoku


What does all of this mean, you ask. Also, the more astute readers will notice I only listed 19 pots, when the assignment was 20. WELL, one pot broke on the way to class the first day, it was very disappointing.

First, the types of clay:

Dillo White is a white clay that has lots of "grog" in it, which basically just means it has little rocks and sand in it. The rocks and sand create their own texture - they also make the clay more sturdy. So if I wanted to make something big and tall, I'd have to use clay with lots of grog in it or else it would fall over.

Balcones is a red clay that also has lots of grog in it.

Porcelain is a white clay with no grog, which means it's very smooth. It's really easy to work with for small things with lots of detail, but when it starts to get larger it will break or fall over if you aren't good at handling it. So far, the only things I've made with porcelain are pinch pots, since I am kind of afraid of it right now. When I get better at building I will probably start using more porcelain.

The glazes are separated into two categories in my head (simplified because that's how the teacher explained it to us in our 2 hour crash course last Thurs): Runny vs Not Runny.

Runny glazes have to be used very carefully because if they drip onto the kiln shelf then you have to buy a new kiln shelf. And by "you" I mean ME, and a kiln shelf costs at least $50 each. Eek. So for the pinch pots, all of the glazes that I labeled as being used "inside" of the pot are the runny glazes, so that when they run they will pool into the bottom of the pot, rather than drip off of the pot and on to the kiln shelf. The other glazes are Not Runny.

He didn't really explain what it meant when a glaze was runny other than, physically, it drips and runs. I don't exactly know why it does that. My best guess is that the metals in it are very susceptible to heat - for example, copper glazes are runny, and I assume copper in very high heat turns liquidy. This is the only explanation I can come up with.

---

One really annoying thing happened today while I was working in the glazing area. Glazes, in powder form, are very dangerous because they are heavy metals and can easily become floaty dust in the air. You're supposed to wear a dust mask when you're in the glazing area if you're using any powder (well, you're supposed to do it in general) - unfortunately I wasn't able to find a dust mask before today, but I figured, OK one time will be fine and anyway I'm not using powders.

Well. This guy decided he was going to mix a huge bucket of glaze from powder. So you know what he does? He gets a mountain of powder, dumps it in a bucket, then dumps in some water and uses a big power tool to mix the glaze. Fine, whatever, except that he decided to do this INSIDE, where other people were working. Of course, he protected himself by wearing a respirator mask (I don't know the real name, but it's like a gas mask but to keep dusty particles out). But he's working 2 feet from where I was standing, so obviously I was not protected.

I had to go and stand on the other side of the studio for probably 10 minutes while he did this. I was pretty annoyed. Nobody else seemed to mind, and when I came back and went to see if it bothered other people, another student was like, "eh, I have breathed in so much pollution in my life it probably doesn't make a difference." The main difference I see was that I have no idea what was in that powder that he was mixing, but there could have been heavy metals like lead, cobalt or copper. Nice.

I'm definitely going to find a dust mask by next week!

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