Guest post by Black Bear
Ceramics Part II: Glazing Over
When last we left my budding ceramics hobby, I had just barely managed to get a few lumps of clay properly centered on the wheel and turned into vessels with both an inside and an outside, which didn’t immediately fall over or lose their shape the moment I tried to transport them to the drying area. This is saying a lot, frankly. Getting a completed piece off the wheel is almost as challenging as getting it on there in the first place when you’re a beginner. But I managed it, and it got a bit easier over time, and I finally reached the stage where some of my stuff could be fired. (We’re skipping talking about trimming, because that’s its own kind of fresh hell in itself, and I don’t have any pictures to illustrate it anyway.)
Before a piece can be fired, it needs to dry out. You remember that this whole process is a melding of Elementals, right? Earth + water = soft clay. Soft clay + air = hard clay. Hard Clay + fire = ceramics. So once you’ve got your earth/water in the shape you want, you let air go to work on it, because it has to be perfectly dry to be fired. If it dries too fast or too slow it can crack, or trap pockets of moisture which will be a problem in the kiln. If that trapped water turns to steam, it’ll cause your piece to break—or, possibly, explode spectacularly, taking out all the neighboring pieces in the kiln with it. This does not make you any friends at the art center. So you wrap your wet piece loosely in plastic, letting it dry out sloooowwwwwly over several days. When it’s finally dry enough it’ll be hard to the touch—but still a bit grainy-soft, you could mark it with a fingernail if you tried. This is called greenware, and it’s ready for its first firing!
Fired greenware is called bisque. The piece becomes hard and smooth, and with the type of clay I’m currently using, it changes color from pale grey to pale pinkish. This is what you can buy at those paint-it-yourself pottery places, and some people stop at this stage and decorate the piece with paint (as opposed to glaze.) Then they’re done, no more firing required. But if you want to glaze the piece (which you do if it’s intended for use with food) then there’s a whole ‘nother phase of the process! Oh boy! My favorite part!
Glazes are made of a combination of pigments and minerals; a main mineral is silica, which is of course the primary component in glass. So when the glaze is superheated on your next go-round in the kiln, it’s going to melt and flow on the surface of the piece. Depending on the chemical makeup of the glaze, it might stay more or less where you put it, or it might glorb right down and puddle up at the base of the piece in the kiln. This is to be avoided, as it means your piece is now attached to the kiln floor with a blob of hardened glass, and you can guess how that might end badly… Part of glazing, then, is getting to know the different glazes you can use and how they react when fired. Naturally, I knew nothing when I took this class, which is how I ended up with a lot of pieces that look kind of drippy.
My art center has a very cool thing available to us neophytes: a wall of sample tiles showing how each glaze reacts when a second glaze is applied over it. It’s not a perfect representation—a lot of the chemistry of glazing is very subtle, and one batch of glaze may be different from another, or something might react differently depending on where it’s placed in the kiln during firing. But the samples give you a place to start; so pretty much everything I’ve done involves combining 2 or more glazes and then seeing what happens!
Glaze names are often confusing; the “dragon mug” you all liked so much in part 1 was dipped in Temple Orange, and then the outside got an additional coating of Leech Blue. While it’s blue in the spots where the glaze was thickest, that funky mossy greenish brown resulted from the second glaze bonding with the first one underneath–and you can see it puddled up around the base, because Leech Blue is super-runny, as it turns out.
Here I played around with Temple Orange and a different blue, and a clear glaze on the outside which fired to a warm brownish gold. I love this—it’s not the most graceful bowl ever but that color combo just knocks me out.
Some glazes can add texture to a piece, as well. This is something called Gold Shino, which I have since learned should be put UNDER another glaze rather than just straight up by itself. It came out looking a bit like burnt cheese, and I think the cracks in the finish mean it’s not food-safe, but the blue lip worked out well.
Just so you don’t think everything I do is orange and blue, here’s something I did with a green glaze and a clear one. Didn’t turn out quite as expected, but it’s still kind of fun.
And the ever-popular tomato dish:
Now, this is all pretty simple basic glazing, and it’s all on my rather chunky beginning wheel efforts. Just to show you the kind of thing I’d love to be able to do someday, here are two of my favorite mugs emphatically NOT made by me. The first one I bought when I was in North Wales a year or two ago; it’s from a local ceramicist, Glenny Pottery. The second one’s an artist who works at the same art center I do; I bought this from her at an art fair last fall. It reminded me of Pooh Bear’s honey pot….
Further ceramic adventures to come, I’m sure… I’ve got about 10 things currently waiting on the greenware shelves at the art center…
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