offcntr: (be right back)
It's the last weekend before Saturday Market. The van is loaded, inventory done, the pots for my next glazing cycle are dry, bisque fires starting. What better excuse to run away for a couple of days?

I may have mentioned that my wife, Denise, is also a craft artist; she makes handmade paper and hand bound books, which she sells through Saturday Market as Pulp Romances. We sometimes play in each others' playground: she'll glaze empty bowls or make small ceramic pieces. I'll pull paper and experiment with different bookbinding techniques. And this weekend, we got to play in someone else's playground.

Heather Fortner is a printmaker based--for a little while yet--in Toledo, Oregon, just east of Newport. She's in the process of retiring to Mexico, and was offering a farewell workshop in Gelli printmaking.

Gelli plates are soft, flexible printmaking plates, that you ink up, and then place various resists--pressed leaves, cheesecloth, paper stencils, feathers--on top, before you lay on your paper, burnish, and pull off a print. You can then re-ink the plate in a contrasting or complementary color, lay down different stencils and pull a second color onto the print, a third, even fourth. There are ways to pull prints from residual ink on the plate, ways to create textures in the ink layer before printing, just a whole bunch of different ways to manipulate the image.

It's essentially mono print, but on a flexible, forgiving substrate. The process was lovely but challenging, especially as we were using acrylic inks, which dry fast, so you had to commit to your design, or see it sitting dry on the plate.

This is my workstation at starting. On the right, you sell the clear plate and ink brayer (roller), top and left, leaves to use as stencils, and bottom left, tubes of printers ink. I started with cobalt blue (of course), cadmium red and titanium white. The first print I did was two-color, in red and blue using the Japanese sea weed. Worked pretty well (see below, left), though I quickly found I needed to move my table out of the sun, as the ink was drying too fast in that corner.

I also quickly got too engaged in the process to remember to take photos, so I have no process shots at all, not even of Denise working (though here's one of her cleaning off her gelli plate). She did some things I didn't, like overprinting on text blocks, and pulling second prints from dried ink residue. (As in the top left and bottom right prints, below.)

All in all, she made a lot of prints...

But then, so did I.

I also found myself being called in to consult on color choices, not just by Denise and Hope, but by Heather, who said I had the best color sense she'd seen in a while, and invited me to help some of the other students choose color blends to overprint on their pieces.

All in all, a very satisfying day's workshop. But we didn't buy a plate to take home. God knows we don't need another art hobby...
offcntr: (Default)
I was recently asked by a member of the Art Center board whether I could help with a restoration. A wonderfully wonky mixed-media sculpture from 1982 had turned up in deep storage, somewhat the worse for wear. It needed a little wood restoration, which is outside my skill set, but also had about five ceramic bits--two hemispheres and three flanges--that were broken or missing, and another hemisphere that had come off, but looked like it just needed to be re-glued.

The original work sculptors had been woodworkers, I think, so they'd turned all the parts in wood, then made molds to cast the ceramics. Fred asked if I knew any wood-turners at Market who could make the molds, and I pointed out that it would probably be just as easy to fabricate the pieces on the wheel. Which is how I spent most of Monday morning (before the power failed) while firing my kiln in a snow storm.

The hemispheres were simplest. Open the clay down to the wheel-head, pull up and in, collar and narrow the top until it closes, not unlike how I throw cat banks and salt/pepper shakers. The tricky parts is getting the dimensions right, but I sacrificed a plastic binder cover to make templates, and used a pair of calipers to check dimensions. I had less shrinkage to deal with, because I'm using white earthenware (necessary to get the proper glaze colors), and since there's no shrinkage between dry and glaze fired, I can actually adjust measurements by sanding if necessary.
enough, including spares
The flanges were a little trickier. Center the clay, open again down to the wheel head, spread the clay out. At the correct width, split the clay, with some coming up to form a short cylinder, the rest moving out to make a flat skirt. Again, check measurements with calipers for diameter, ruler for height, and template to set the curved transition. Made three to cut six, and used a fourth, unsuccessful attempt to calculate shrinkage (Marking a six-inch span that I'll then measure at leather hard.)

I created a template on the computer to show me where to cut down the thrown pieces, sized using the shrinkage from above. I centered each piece, using the bulls-eye circles on the template, and using a combination of eye-balling and ruler, and a very sharp fettling knife, I cut six half-square flanges out of the three originals. Now it's time to dry, while I chip out broken bits and compare glaze samples. I'll be using commercial glazes from Georgies, I think, rather than trying to mix my own.

Saved!

Feb. 8th, 2019 05:41 pm
offcntr: (Default)


Since I spent all of Thursday trimming pots and pulling handles, I made it to Friday afternoon with two bags of clay left. Fortunately, turning up the heater and cutting down the lumps of recycled clay worked fairly well. Clay was wildly inconsistent, almost leather hard at top and edges, still gooey at the bottom (and in the nougat-y center), but that's what a pug mill is for.

Also fortunately, Denise has Friday off from both work and classes, so helped me run everything through the mill--I fill the hopper and pull down the handle, she catches the extrusions as they come out the other end. Everything runs through twice, randomized to mix the firmer early pugs and the still-squishy later ones, and on the second pass we also turn on the vacuum pump, to remove any air bubbles. Denise then bags the result, and I twist-tie the bags closed and stash for later use.

Or in this case, immediate use. I'll probably start making plates with the softest pugs tomorrow morning. We processed just about two dozen bags of recycled clay in three hours. At 15-18 lbs. per bag, that's almost 400 lbs. more clay than I had this morning.

Spectators

Jan. 28th, 2019 11:40 am
offcntr: (bunbear)
Saturday was the Art Center's annual meeting and open house. It was also the day Denise and I were loading the kiln, so we had spectators. I don't mind, really; years of teaching experience leave me ready to lecture--or at least explain--at the drop of a question. Had a few familiar faces from other parts of my life, one of whom took this picture of me moving ware boards and was kind enough to text me a copy.
offcntr: (chinatown bear)
There's something mesmerizing about a kiln as it loads, especially a bisque, where pots are stacked on other pots, or inside, or interlocking. It's really a puzzle in three dimensions, balancing the fragility of the the dry clay against the need to pack in as much as possible. Here's the four stages of my last kiln.

The bottom layer is pie plates, filled with dessert plates; they fill the shelves pretty tightly, leaving only room for one inverted toddler bowl at the center. (I think I have another pic for the Mandala tag.) Second layer is a little more random: batter bowls filled with soups topped with toddlers and cat foods, Small colanders inverted in the middle, mixing crocks, also inverted (to fit under the curve of the batters), and a few tumblers just to take up space.

At this point, I start tall-stacking: casserole stacks two and three high, with plates in between to take some of the pressure off the casserole lids. Tall mugs on painted mugs, pilsners on tumblers, tiles leaning, on edge, in the gap between stacks. Lastly, a half shelf--there's about 3-1/2 inches of unused space, enough for stacks of three plates, or another toddler bowl.

Then close it up, start it firing, and lay out pots to dry on the soon-to-be-hot lid.
offcntr: (Default)
A long time ago, I wrote, "Making handles is the penance I pay for the ease of throwing cups." And it's kinda true.

Throwing mugs is easy, especially tall mugs. The sides are straight, the only real fussy bits are the base, made with a profile rib, and the lip. In between, they mostly just need the throwing rings smoothed out with a rib. (Although I need to replace my rib; it's wearing into a curve, and I need it straight, dammit!)

Handles are fussier, especially if you're pulling them directly onto the cup. I'm not, so I have a little leeway. If I mess one up in the pulling, I don't have to clean off the mug and smooth out the scoring; I just set it aside and start another. It's a technique I learned years ago from Dennis Parks at Tuscarora Pottery School, and I use it for everything but pitchers.

First, you wedge up your clay, then pinch off a bit. Roll it into a coil on a smooth surface (this is a piece of drywall. My table is canvas-covered, which leaves an extra texture to get rid of.), then taper into a carrot. Thump both sides on your drywall to flatten it out.

Now comes the fun part. Hold the thick end in your non-dominant hand, pointy side down over a container of (preferably warm) water. Using the thumb and forefinger of your other hand, with water as lubricant, pull and shape your handle, tapering edges, grooving front and back. Once it's the proper shape, rotate it so it's butt side down, handle curving up and over 'til the tip touches down again.



Repeat forty times.

Then go do something else for a while. Smooth and stamp the mugs, turn them over so the bottom dries a little. Throw a bag of plates, have lunch, do dishes. Let them sit four or five hours (less in summer), so they're slightly firmer, and no longer sticky.

Now it's time to put it all together. Start with the mug: score and slip the handle attachment points. Take a handle in one hand and a wire cheese slicer (roller removed) in the other. Cut away the butt end of the handle, curving to match the cup, angled slightly so the handle springs up and outward.

Holding the handle between thumb and forefinger (thumb on top, finger supporting), press the handle into the cup. Your thumb will make a little dimple in the top for the user's thumb to grip, and the handle will spread a little wider at the top, which is visually and structurally stronger. Press the bottom into place, smooth and align the outer edges of the top, and clean up any extra slip or score marks. Adjust the curve of the handle from underneath with your finger. Go to the next one.


Flame on!

Dec. 10th, 2018 03:45 pm
offcntr: (Default)
More pictures from the storage unit: A raku class I taught at the EMU Craft Center sometime in the early 90s. I'm actually still in touch with three of the folks shown here; two more, sadly, are no longer among the living. And at least two I have no recollection of whatever. Hey, I've inhaled a lot of (sawdust) smoke over the years. The brain cells get dusty.

Raku is a ceramic process originating in Japan, where low-fire pots were rapidly brought to temperature in very small, wood-fired kilns, then pulled out red-hot and plunged in water to cool. Raku tea bowls were highly prized for the tea ceremony, and the firings eventually became a social event, where pots were provided for guests to show off their calligraphy on. They were then fired on the spot, and much admired before being taken home as party favors.

American raku usually uses a gas kiln, and adds an extra step: After removing from the kiln, and before cooling, the pots are sealed in a metal barrel with sawdust, leaves, newspaper or other combustible material. (A steel trash can with tight-fitting lid works well.) This post-firing reduction emphasizes crackle in the glaze surface, as carbon is absorbed there. Carbon absorption makes unglazed clay surfaces black as well. And it's also possible to get metallic lusters, mostly from copper, and rainbow-hued matte glazes (also copper) as well.

Credit goes to Denise for taking the pictures. I think I just gave her my camera and told her to be careful not to set it on fire.

On the left, Penny McAvoy bravely pulls a glowing pot from the kiln; Kathy Lee scrubs a layer of ash off a plate to reveal the black figure, wax-resist-on-crackle-glaze pattern beneath.

Kathleen Fitzgerald and I pull still-not-very-cool pots from the reduction chambers, while TK McDonald prepares for the next batch of hot pottery.
everybody has something to be proud of


offcntr: (Default)
Among the photos found in boxes buried was a black-and-white series from my graduate school days, recording an Advanced Ceramics class clay mix. We'd begin by dry-mixing hundreds of pounds of clay and minerals on a table-top in a 2x6 frame. Afterwards, we'd add blunged, screened slip from the recycle buckets, mix by hand, knead into a solid mass, then run it through the pug mill. In a three-hour class, we'd mix up a ton-and-a-half of clay, with time to clean up the shop and pose for a group picture at the end.

In retrospect, it was horribly unsafe. All that silica-bearing dust in the air, and us in cheap, disposable dust masks. (Even worse for those of us with beards, as dust-laden air gets in around the edges of the mask.) But it was a great team-building exercise; we had a read feeling of accomplishment, knowing we'd made the entire term's supply of clay in that three-hour class.


First add the dry ingredients, fifty-pound bags of fireclay (Greenstripe, Lincoln), ball clay (OM4, I think), Custer feldspar and talc as body fluxes. Possibly some silica, too, I'm not sure at this late date what went into a cone 6 stoneware. Then add the glop, five-gallon buckets of recycled clay slip.

Afterwards, it's like making egg noodles from scratch, everybody makes a well in the flour, pulls in some egg, mixes and kneads.

Lumpy, uneven balls of clay get rolled in more dry mix and run through the pug mill, then bagged for aging and eventual use.

Last of all, clean up and try not to look too exhausted for the group photo.
offcntr: (bella)
...holder.

Honestly, normally, this woulda gone on my list of things I'm not gonna make: napkin holders. But it's part of a special order, which makes it different.

The difference? Most of the pots on my Oh God No, Nope, Never list get suggested thusly: You know what you should make? [Ridiculous suggestion redacted]s! You'd sell a million of them! Whereas a special order says Could you make just one? For me? As part of this bunch of tableware pieces I'm also willing to pay for?

I mean, seriously, how can I say no?

Besides, it's January. I have time to mess around with design ideas, even if only for a one-of-a-kind item. (Though I'll probably make two, just in case.)

So here's my step-by-step attempt to make a napkin holder.

First, throw a bottomless cylinder, with smooth straight sides and a reinforced top, not unlike a utensil crock.
bottomlessa little like a tool crock
Then dribble water onto the wheel head, and drag it under the pot with your cut-off wire. This allows the bottom to slide as I reshape it from a round cylinder to an oblong rectangle.
stretch n slidewith corners!
Let it get leather-hard overnight, then mark where I'm going to cut away and reinforce the edges with an extruded coil that's about the same size as the bead around the top. After that, cut out the ends and smooth everything down.
reinforcementscutaway view
For the last step, I cut a slab to match the inner dimensions of the piece and attached it level with the bottom of the notch. Then it's dry slowly, bisque, glaze, and hope those big, unsupported flat surfaces don't droop in the firing. 
et voilawell, flattish

offcntr: (Default)
 Now that Clever Girl is bisque-fired, it's time to consider surface treatment. The dino herself is simple, if messy: Wax over the colored porcelain eyes, teeth and tongue. Iron oxide wash, brushed on and sponged off again to leave traces in the creases and crevices. (Leaving me red-handed for the next several days, worse than cooking beets.)  Maybe some white underglaze on the belly, white stripes across the spine. 

The book needs content, though. I impressed the title into the spine--The Big Book of Dinosaurs--but intentionally left the pages blank. Since my head-canon is that my velociraptor thinks it's a cookbook, I need her to be perusing the herbivores. These two are sufficiently close, alphabetically. Also fun to draw. Here's the process.


Beginning with the blank page, first define the border of the illustration, then draw the dinosaur. Letter in the heading, then use a grey wash to greek-type the body copy.

Turn the page and repeat. Next, I brushed wax resist over the edges of the page block, then brushed a chrome oxide wash onto the cover, sponging back a bit, which leaves extra color in the canvas texture, and especially in the rubber-stamped title in the spine. The result looks astonishingly like the green, cloth-bound books of my grade-school library.

Final results. Well, semi-final; the firing will probably tone down and darken the colors considerably. We'll just have to wait and see.
offcntr: (Default)
I've been poking around the archives, trying to find the posts on glaze and overglaze recipes, because every now and then someone asks for them. I've finally found both, and have retagged them glaze recipes, so they'll be easier to find.

But recipes aren't the only important information. There are details of mixing and application that need to be considered.
 
Consistency. Glaze recipes tend toward dairy metaphors. A glaze should be the consistency of milk, cream, half-and-half. I found this maddeningly imprecise, and a real problem when painting on vertical surfaces. Too thin a glaze coat, and the base is brown and unattractive from the iron in the clay body, but too thick, and the picture runs off the pot. After far more years than I'd like to admit, I finally bought a hydrometer. It's a glass tube, like an oversized thermometer, with a lead weight in the bottom and a paper scale, graduated to measure specific gravity. After mixing the glaze thoroughly and waiting for it to stop spinning around in the bucket, I lower the hydrometer into the glaze and let it float, then read off the scale where it's at the surface level. The specific gravity of water is 1.000; I've found 1.500 works perfectly for me. (As an aside, this means there's twice as much water as dry materials in my glaze, so for my standard batch of 14,000 grams, I'm actually mixing up 42,000 grams of glaze--a bit over 90 lbs.)

 I also find that the glaze gets thicker with use, whether from evaporation or absorption of water into the bisque, so I check a couple of times a day, and add water as necessary.

Thickness. The thickness of application of a glaze depends on several factors: how you apply it, for how long, and how much water the pot can absorb. I dip or pour the glaze--spraying leaves too fluffy a surface for my overglaze decoration--for a count of four (one, two, three, four--out again), which I long ago determined is actually about three seconds. Apparently, I count in waltz time, 3:4. Smaller pots, especially thinner pots like soup or toddler bowls, may need a little more time in the glaze to get a proper coating. I usually dip lids for casseroles, cookie jars, honey pots twice to get a proper coating.

Settling. If the glaze isn't fully suspended, you're not going to get an even coat. If your glaze is high in slightly soluble minerals, like nepheline syenite, it'll want to settle to the bottom of the bucket and form a rock there, while leaving just enough in suspension to fool you into thinking you're still applying glaze. Mix early, mix often. And a teaspoon of epsom salts, and a bit of aging, doesn't hurt either. I now mix my glaze for each firing during the previous firing--four to six weeks before I actually start glazing again. The extra conditioning time does wonders for glaze suspension.

Overglaze application. If you're used to underglazes, you're gonna put the stains on too thickly. You want it the consistency of india ink, maybe a little thinner. And that's for the initial line drawing, at full strength. Dilute with water to create washes, shadows, lighter tones. There's almost homeopathically small quantities of red stain in the water when I glaze bunny ears. I want only the palest of pink. Some colors have more tinting strength than other. Cobalt carbonate can be diluted many times and still give you blue.

If your stains are blistering, or, worse, burning out to a scabby grey scale, you'll really want to dilute them down some.

Firing temperature. There's a lot of variation in the way potters fire to cone 10. I know a potter who fires cone 10 flat on the pad, 11 nearly touching down to get the glaze effects he wants. If I did that, every picture on every vertical surface would be a blurred smear. I want cone 10 just touching at its tip. If the kiln is firing unevenly, I may fiddle with the damper to try and catch up the cold end, but not past that point. I can usually count on carry-over to drop that last half-cone, particularly if the top of the kiln is cooler than the bottom at shut-down.

Other firing ranges. I'm firing cone 10 in reduction; I've also used cobalt, iron and rutile at cone 6, reduction. Not sure how they'd work in oxidation; some metals, iron in particular, act as a flux in reduced form, but a refractory in oxidation. Experiment with a reliable white/whitish base glaze, moderately glossy, and be prepared to add Gerstley Borate or Ferro Frit 3134 to your oxides and stains. I wouldn't overglaze on a matte glaze if I intended to use it for food; I'd worry that the oxides wouldn't be sufficiently absorbed into the glassy matrix.
offcntr: (window bear)

Visiting my brother in Wisconsin, which, in addition to revisiting embarrassing family stories, allows me to revisit embarrassing pottery.

Actually, it's not that bad. A lot of the pottery I've given him over the years is still recognizable: a large bunnies serving bowl, robin cookie jar, batter bowl with the happy hen pattern. This one, though, goes way back. Not quite to my Wisconsin days, I don't think, but certainly pre-Off Center Ceramics.

It's an oval baking dish, about 6x9", glazed in Craft Center temmoku and Woo's blue. I did a lot of these, early on. The walls are thrown first, with no bottom, then formed into an oval. At soft leather hard, a slab bottom and crock-style handles are attached. Can't tell if these handles were pulled from a (very small) coil, or whether they were thrown and then cut and attached. They're a little small for practical use, almost dainty.

I still use this technique to make oval platters, but not bakers. The failure rate was too high both in the making (cracks along the seam if moisture wasn't correctly matched between bottom and sides) and, occasionally, the baking. Apparently, a slight mismatch in moisture, not great enough for cracking, might still introduce stresses that would show up when they were heated in the oven. Much safer to go with my current, squared bakers: thrown in one piece, deformed slightly while still wet, then pulled handles attached at leather-hard.

Though this is a pretty, pretty pot.
offcntr: (spacebear)
This is not poop.

It's clay scrap, just pulled out of the recycling bat and ready to pug-mill. Except I don't have time just now, so it's gonna get bagged and set aside until next week, maybe.

I produce a lot of this stuff: wet slop from the throwing bucket, dry scraps from trimming, the occasional broken, cracked or trimmed through piece of greenware. It all goes into four-gallon plastic buckets in front of my wheel where it slakes down to the consistency of, well, poop. Wet cow poop, fresh from spring pasture.

It has some of the smell of poop, too, anaerobic bacteria digesting oil and skin flakes from my hands and traces of organics from the clay. I sometimes wish I'd contacted Mike Rowe back when he was still doing Dirty Jobs. He'd have loved this stuff.

I love it too; I get two or three hundred pounds of recycled clay every time I empty the buckets. After enough time.

Traditional pottery recycling bats are plaster tubs. They're heavy, fragile, but do an excellent job of removing excess water from clay slurry. If you're not in a hurry, though, you can go lighter and easier.

This is my recycling bat: A frame of 2x6" pine, with a mesh bottom: plastic window screen over 1/4 inch galvanized hardware cloth, supported with 1x2" furring strips around (and across) the bottom. The whole thing is mounted on casters, so I can wheel it in and out from under the ware rack.

When it's time to recycle clay, I wheel it out, line it with a thrift-store bed sheet, folded double, and ladle in all the slop. Once it's heaping full, I fold the sheet edges over the top to keep out dirt and bugs and roll it away. Four to six weeks later, (twelve, this time. It was a wet winter) it's ready to come out of the bat and run through the pug mill.

Then back on the wheel. It's the circle of (a potter's) life.
offcntr: (spacebear)
The Letter Tea!

Time to make teapots again. So many parts. So many steps.
offcntr: (berto)
I've been doing tumblers for about a year now, basically cylindrical glasses based on my tall mugs, but without the handle. They seem to be popular enough, but I'm not sure I like the form. Maybe my hands are getting creaky with age, but they just don't seem comfortable to grasp.

So I've been experimenting with a different shape, narrower at the bottom, not unlike a pilsner glass. I've made a couple for my own use so far. This time, I'm making half a dozen to see if I can throw them consistently, and to see how my glaze patterns fit, as the taper is just about the opposite of my regular painted mugs.

Results

Nov. 16th, 2016 03:09 pm
offcntr: (berto)
I always stress when I fire right after Jon. He'll have a harrowing tale of kiln misfortune/misfiring, and I'll be right in his footsteps, worrying that the same thing will happen to me. Never mind that we stack the kiln differently, fire different schedules to different preferred temperatures. I'm sure I'm bound for disaster.

This time, it was temperature and reduction inconsistencies. The top was too hot, bottom too cold, oxidation spots in places that had traditionally been reliably reduced. One of which ruined a special order platter.

And this time I was literally following right after him; he finished unloading around noon Saturday, Denise and I started refilling the still-hot kiln about 12:30.

We closed up around 5:30, and I came back to light the kiln a little after 7 pm. Because I was firing on a Sunday, I came in extra early (before 5 am) to continue the process, so I'd be done with body reduction in time to sing in church at 9 am.

I messed up, a little. There are lines on the damper (a mullite kiln shelf) indicating different points in the firing, but, since the chimney's been adjusted a few times, there are actually about three sets, marked 1, 2, and two 3's. Between bad lighting, less sleep than usual, and concern about making my self-imposed schedule, I used the wrong line when I put it into body reduction. The damper was about 1/4" too far open. I finally noticed a half hour later, when it was time to take it out of reduction. Concerned that the bottom might not have gotten the reduction it needed, I put it on the proper line for another ten minutes and hoped for the best. (Didn't want to risk more for fear of over-reducing the top of the kiln.)

Other than that, it was a fairly normal firing, at least until the end. Top and bottom were within half a cone of each other at cone 4, normal for me. The margin had widened to a full cone at cone 8, though, so I tweaked the damper a couple of times to try and even it out. I eventually gave up with cone 10 down on top, but only halfway on the bottom. Carryover heat gave me a little more on the bottom after I shut off the burners, but it also dropped cone 11 on top.

When we opened the kiln Tuesday afternoon, though, it was much better than I'd feared. Pots in the hot part of the kiln were still good; the images hadn't blurred or run. Body reduction was a little light in the bottom--my fault--but only one really bad spot of oxidation, down at the bottom right, where it ruined one covered casserole and lightly side-swiped three more. They're still sellable, though, which is good because I didn't have any in stock.

And those four serving bowls? Turned out gorgeous.

offcntr: (spacebear)
Still waiting on my clay order, so I'm making stick butter dishes. I used to make these the easy way--domed plates thrown on the wheel. And nobody bought them. Too big for the fridge, I guess. I futzed around with different ways to mass produce them, including an extruded version with a horrific failure rate--the top started as a longer ceramic rain gutter, and it was almost impossible to keep them from warping. I finally came up with this system, which is time-consuming and a huge number of steps, but produces a nice-looking, fairly consistent butter dish.

I start by throwing a closed cylinder on the wheel. The process is the same as for banks, start with a tall-mug cylinder, then collar in the top until it closes off entirely. Rib smooth, with a flat or slightly domed top, then cut off the wheel and leave overnight.

The next morning, I paddle the closed cylinders into a rectangular cube, then set them aside to continue drying. I also extrude the forms that will make the lip of the dish.

After a couple of hours, I bring the dishes back to the work table and, using a couple of boards as template, trace a cutting line all the way around the form about 3/4 to 7/8" from the bottom. Since the paddled sides are still slightly curved, I attach four little ball feet to the base, paddle the outer sides to match the faces of the dish, and set aside to dry some more.

Round about evening, everything is firm enough to go to the next step. Using a sharp fettling knife, I cut the cylinders apart along the cutting line, then moisten and smooth the cut edges. The top is set aside while I add the lip to the bottom.

Long sides go on first, scoring and slipping the side of the dish and the edge of the extruded molding. The lip stands about an eighth inch above the cut edge, to hold the lid in place. The moldings stick out an inch or so at each end.

End pieces are cut, bent to fit and set in place. Corner joints are mitered with my homemade cheese cutter, then the whole piece is scored, slipped and attached. When all sides are finished, the corners are smoothed and rounded, excess slip is cleaned out of the gallery, and extra clay scraped off the bottom of the join with a stiff rib.



The dish is then reassembled and set aside to dry.
offcntr: (snoozin')
Since I've less than 100 lbs. of clay left until the truck from Clay Art Center arrives, I've been working on special orders, and projects that are time-consuming rather than clay-consuming. Including the altar set.

I made two of each piece, of course, plate, chalice stem and bowl. Dried them slowly and carefully, using plastic as needed to make sure top and bottom pieces matched in moisture. Trimmed them when leather hard, then scored and slipped the top of the stem and bottom of bowl.

With the stem centered on the potters wheel, I attached the bowl, doing my best to keep it level and on-center, then wiggling it gently to set the joint. Afterward, I flipped it over, worked a small coil into the seam to reinforce, and smoothed the inside with a blunt wooden sculpting tool. I also scraped and smoothed off any excess clay from the inside of the base.

Patens dry much slower, so I just flip them over and leave them to trim in the morning.

Flat stuff

Dec. 15th, 2015 10:15 pm
offcntr: (live 2)
I'm starting to work on one of my winter projects, a series of tiles for a kitchen remodel, eighteen in all, in a couple of sizes. Hand-painted, of course. It's times like this I'm really glad I bought that surplus slab roller from the UO Craft Center back in 1998.

Tonight I'm starting on the first set, six 4x6" tiles for a backsplash. First, I roll the slab to the proper thickness--about a quarter inch--with my slab roller. I lay a sheet of latch hook rug mesh between the slab and canvas and roll it again. (This gives a texture to the back side that will help grip the tile adhesive on installation.)

I then flip the slab over and smooth the top surface with a rubber squeegee (thank you, Goodwill) and silicone rib. I cut out the tile with my punch cutter, transfer it to a piece of drywall, then eject it with the built-in spring-loaded piston.

Keep cutting tile until I run out of slab, then wedge up the scraps and roll again. Finished tiles are stacked between sheets of drywall scrap; slow, even drying will keep the tiles flat. I can fit two tiles on each piece of drywall. Edges are sealed with duct tape to keep crumbs of plaster out of my clay.
offcntr: (spacebear)
Mad science report:

Hard as it was to wait, I didn't open up the saggar firing until the rest of the kiln was completely unloaded, Denise and I'd had a lunch breakā€¦ and Shelly arrived to see how our experiment had come out.



Results were great fun--some lovely amber-colored flashing on the porcelain slug, with speckles where we'd dusted the copper. Also a brown, ashy glaze on the snail, bunny, and whistles that seems heaviest near the bottom, tapering to almost black on the top. We're speculating on the presence of soda and silica in budget charcoal briquettes, since we certainly didn't sprinkle in that much soda ash.

In any case, Shelly's excited to start making more things out of cone 10 porcelain, and I'm kinda tempted, myself. I've actually got a couple of bags, rock-hard, but if I start slaking them now, maybe by my January firing I'll have some more things to put in the box.

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