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(14 July, 2000)
I am in the middle of building another teapot. Teapots are one of those things. I have tried at least a dozen, of which two are now in use and one sits at my lab, awaiting a visit to Bob the Dentist. (Teaholes fulla glaze.) It's funny, I know two people who are Bob the Dentist: Bob Gross, in Seattle, and Bob Stern, who got mentioned last time.
Be that as it may, a teapot is a towering thing for a student potter of my stripe and experience level. (I've probably said this before, but it may merit the repetition.) The one I'm working on now is probably doomed to failure, but it has been a happy exercise so far, and I think I will do a bit of documentation of the process. This will be seriously incomplete, because I can't show you photos of the early stages, but here's how it's going.
(17 July, 2000)
On Wednesday evening I threw a 13-inch platter. That is what I think I set out to talk about in this section, but the teapot threw me off course. Teapots are like that: they tend to expand without limit... but I digress. The platter was a happy thing, even though I flopped it the first time, as I usually do. Perhaps unusually, I flopped it in a vaguely novel manner: I finished it, realizing that the wall felt really strange in several places; then I stopped the wheel and looked, and realized that the wall was torn in those places (!) -- the clay was so "short" (nonplastic) that it had shattered while I was throwing it, while it was wet, while... argh.
Shattered or now, though, the platter didn't collapse. Maybe I really am learning to throw. Well, it didn't collapse on its own, but I took the clay off the wheel and scrunched it into a blob so I could start again. Fortunately, it had been a bit dry to begin with, so it was only moderately squishy.
On Jeff's advice I kneaded some grog into it (though that is seriously unlikely to make it any more plastic, grog, which is ground up fired pottery, does increase the wall strength slightly, and it does dry out the clay a bit) and tried again. This time the clay sheared and split almost as soon as I started actually throwing, after centering the clay and pushing down into the middle of it to create the beginning of a shape. I wasn't having any of that kind of crappy behavior, however, so I made a hissing noise at it to put a proper fright into it, compressed the rim (such as it was) rather firmly and primly, slowed down the wheel and my own attitude, and took a lo-o-o-ong time, being careful to compress and dry and check frequently. That was successful, though when I was done there was one small divot that I had to pat a bit of clay into.
Then I painted white slip on the inside, cut two rings into the slip coating as accents, cut the platter loose very badly from the batt, and left it to dry for a day.
On Friday I went back, trimmed the bottom fairly flat, and (ahem) applied a ring of clay made from the trimmings, which will eventually serve as a footring. The platter is now covered in plastic wrap and is equilibrating, cooling its nasty little heels until it is firm enough to trim for real. (The new footring is a bit squishy yet, not as dry as the rest of the object; this is a prescription for trouble, hence the time-out for a nap.)
On other fronts, I am helping to restore a somewhat battered electric kiln, and I am probably going to build a very small (1 cubic foot) electric kiln, on the side, as an exercise. I still haven't painted the pottery lab, and Chris Daniel has been giving me a hard time about that, entirely justifiably. I hope I can get my act together and do the painting soon.
I have also put in three new fluorescent glaze tests, the two flameproof porcelain tests (actually three, but one's just a duplicate), and a bowl on which I sprayed what should be a black aventurine glaze, if it works. As my father would have said, "We Shall See What We Shall See." I hope they will fire the kiln this week, but it will probably wait for the weekend, and I won't see results until about the 24th of this month. Sigh.
(22 July, 2000)
Oops, I meant the 31st, not the 24th. As it turns out, however, they did fire the kiln, and I will get it all back on the 23rd, which is tomorrow.
It occurred to me that I had probably put too much flux into two of the flameproof tests, and that they might be glaze rather than body at cone 11.5; this was sufficiently disquieting that I left Jeff (the teacher at Glen Echo) a piece of voicemail about it. Later, I went down there for class and to see him about this. The front of the kiln was almost completely bricked up at that point; we talked about it, but he decided to fire anyway, and I had the pleasure of watching him complete the door and candle two of the burners.
I returned the next evening to clean up the footring on something, and the brick that blocks the spyhole was turned to allow some airflow. The inside of the kiln (which I looked at only for a very short time -- I don't really need cataracts) was a lovely orange.
I still have my fingers crossed about whether those flameproof things have melted; while there is typically a fair amount of difference between a body and a glaze at any given cone number, the difference between 3% flux / 97% kaolin and 10% flux / 90% kaolin may very well be sufficiently substantial to cross the gap at typical porcelain temperatures.
(I should, perhaps, point out that the difference between a body and a glaze in the lowfire range is large; lowfire glazes can, for example, contain large amounts of lead, which is not a common body ingredient. By the time you get to high-fire porcelain, however, you can use lowfire porcelain as your glaze base. That is, a good body formula with some extra flux added to it is not far from a viable glaze, and in some cases may even be a viable glaze. The usual difference is that you can't put too much raw clay into a glaze that is intended to go onto bisqueware, because raw clay shrinks when you heat it up, and the glaze tends to fall off as that happens. You either have to reduce the clay content, or calcine some or all of the clay, unless you are glazing greenware and firing it only once, as some people like to do. I could get into a discussion of the relative merits of once-firing and twice-firing, and of my experiences with calcined kaolin, but I don't think this is quite the right venue. Maybe in my glaze-progress report, at some point.)
In the meanwhile, I continue to work on the lugs for the current teapot, which I've already linked to above; and I'm building a small round vase out of reconstituted slop-bucket clay. For some reason, which I cannot entirely fathom, I really like walking into the pottery, digging some junk out of the slop bucket, grabbing some turnings that someone is discarding, and making a blob of clay from which I can then throw something. Mind you, I don't do 9-pound blobs this way, so I'm not likely to throw a whole lot of slop-bucket platters; but I have certainly done three pounds at a time.
In its current state (it's on the shelf, drying) the small round vase is pleasantly red (that is, it is red greenware). My guess is that the trashed piece I fished out of the glop on Tuesday afternoon had been covered with red or brown slip, which I proceeded to knead into my hunk of stoneware.
I think I'm going to do The Bad Thing here, and put up a photo of this thing in its green state. This is probably about as smart as talking about an unfinished story, but hey.
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I also have to think about glazes, and what I'm currently leaning toward is something like this:
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Only one problem: I've never fired this glaze on stoneware, and I have no idea what it will do. Time, I think, to make a ring of stoneware test tiles.
I should mention, btw, that I have tweaked the glazetest
image. The light wasn't as good as I would really like,
and the resulting image was slightly blah and fuzzy, so
I ran it through the "unsharp mask" filter in
Photoshop(tm). It's sharpened 100%, with a 1-pixel
radius. I'm surprised at how decent it looks.
More as it happens and as I get a chance to scribble
about it.
Pseudo-mailto: jon [at] bazilians [put it here] org
Last modified: Mon Jan 29 20:16:13 PST 2001