Hulk

Files touch* my trimming tools, so I file them. It doesn't take long to bring a sufficient edge back, and hence, it doesn't take long to dull them either**. We have some knives (and other tools, e.g. twist drills) in the house that files don't touch, and hence, we turn to the array of specialized sharpening tools... Heat generated by grinding can alter the alter (ruin) the tool's hardness, depending on the material, and how (or if) it was tempered. *where "touch" means they cut chips, or "pull" chips. Files are hard, however, even a sharp/new file won't cut material that is almost as hard (or harder) very well. **trade-offs: cheap - expensive wears quickly - wears slowly sharpens easily - more difficult to sharpen flexible/tough - brittle

I was using a pyrometer* from the start. Early on, I was setting cone packs in front of the peep holes. I'd look at the cone packs as the kiln reached target temperature. Painted lines of iron oxide wash on the cones helped; the cones can be difficult to see when everything is orange/yellow hot! Be absolutely sure to acquire the proper kiln glasses to protect against damaging rays and any flying bits. As experience grew, I became more dependent on my notes and the pyrometer readings, and less dependent on watching cone packs during firing. I'm still placing cone packs on each shelf, however, I look at them afterward. The potter I bought the manual kiln from fired their cone 5/6 clay to a "soft" cone 7, so, I did the same, which was way too much heat work for the red clay I was using. Now I'm using clays that mature at cone 5, so that's what I shoot for, a solid cone 5, which typically meant the middle shelves bend the 6 cone a bit. I believe you can expect the sitter cone to bend before the witness cone(s) of the same number do. For what it's worth, I was setting the sitter timer and the drop switch up just in case something dreadfully distracting occurred whist firing; I never depended on the sitter, instead, was watching the pyrometer, the time, and the cones. I've learned a lot the hard way, and everything noted above, I'd read about in this Forum! ...even so, I still "had to" make my own mistakes. Next up, brand new numerically controlled modern kiln with "zone control"! ...very much planning set up and watch cones through the peeps, starting out, for the kiln's pyrometers may be a bit off. *Dual Input Pyrometer - Kilns | Ceramic Pottery Kiln, Glass Kiln, Pottery Wheels | Skutt

Things that may help: Kiln glasses - to protect your eyes from harmful rays and any flying bits - so you can watch witness cones through the peep hole(s). Cones tell the story! Pyrometer - once you've dialed in your schedule(s), you may just watch the pyrometer, then check your witness cones afterward. Powered kiln vent - moving a tiny stream of air through the kiln a) provides oxygen, b) helps keep the amount of yucky fumes down, and c) helps your kiln last Testing! It might take a few runs to get dialed in - each clay (and glaze) may present a different challenge. Notebook - take notes! It can be hard to remember what worked after a few years... My first kiln was fully manual - three high/medium/low switches and a "kiln sitter" (which had a timer and a drop switch that would actuate when the small cone, or bar, melts). For bisque firing, I'd run the kiln up to about 200F the night before - thinking that by the next morning, all would be very dry. From there, I ran on high up to my target (1950F), with a half hour hold at 1500F. For glaze firing, I'd run up to target temp (cone 5) on high, drop 100F, hold there for half hour, then set all on low for a slow cool to 1850F afore turning everything off, including the kiln fan. I'm holding at 1500F for the bisque fire on account of I'd found the red clay (and to a lesser extent, brown and buff clays) behaves better when it gets a longer cook. My guess it's the larger off-gassing bits that get burned out better with more time. I'm dropping and holding, then slow cooling for the glaze fire because it seems to help with "healing over" glaze defects. Hope that helps! A fully manual kiln requires some attention. That said, perhaps your kiln has a controller? lol! Any road, be safe.

I've used a layer of Murphy's soap on the cake, pie, and loaf pans to help the plaster release.

Hi Carol, Welcome to the Forum! I use tape a lot (perhaps due to having worked in the painting trade). On greenware, however, tape may not work very well. I've had some good luck with cut paper stencils, which sometimes last for several wares, however, sometimes it is a one use deal. If there's a bit of bleeding along the edge, I cut it away later.

The problem solutions I've tried out (and am happy with!), not new; some are used by many others, some are not popular at all. For the second day of Wheel I class, I brought a large (large!) grout sponge to clean up with. From there, I cut up another sponge into purposed shapes/sizes (credit Bill van Gilder). The little round sponge that came with the tool kit saw enough use to eventually wear out (I didn't get a new one tho'!). Leaving the work areas clean, that's required at the local JC ceramics lab. It's still a habit; I wipe down all. That's one - likely a very popular re-use (grout sponges often have rounded corners, which I like better than car washing sponges; look for tight cell structure and soft feel). Likely on the other end of the popular spectrum, I use a pointer tool for initial carving away of un-round bits when trimming. Background, my hands don't alway work the way I'd like; I pretty much have to use both hands on the trimming tool, hence, no steadying finger on the ware. Background ii, I expect the upper portion of the wares to be finished; when trimming, it's the bottom half (or third) that gets attention. I leave the ware on the bat until the top portion is approaching leather hard, then wire it off, which often leaves a step on the bottom. Even with two hands, it's a challenge for me to round the ware with cutting tools. The point does not follow the contour of the work; it dives right in, boom, round, and boom, flat. There's the bottom and outside edge of my foot ring. From there, I go to the L (or J) shaped cutting tool. If I were tempted (?) to go somewhere in the middle, perhaps the various marking, burnishing, and chattering methods...

Covering glass/glaze can be challenging, testing recommended. Priming may help. Test how well the paint adheres to the test pieces (destructive test!). The flat finishes are generally less durable, more prone to staining and scuffing. We* used DuraPoxy on cabinets, strong stuff. In our own house we used a competitor's similar product, ProClassic. They don't come in a flat finish, however, and don't brush particularly well. Try adding a shot of Flood Floetrol to improve brushability (of waterborne paint); it may help the paint smooth out as well (less brush marks). *I was in the new and repaint trade for a long time - commercial and residential.

Any chance the clay composition/recipe had changed? Curious, that the cracks are appearing on the insides, in a circle. While I don't believe that clay actually compresses (forced to occupy less volume than before), nor do I believe that the potter can wring water out of clay with their fingers (or a tool), I absolutely believe that how the clay is worked makes a vital difference. The clay swirls opposite the direction of the wheel; I prefer the term "flow" - that's what it looks and feels like to me. The walls get a lot more work than the base - around and around. Working the base so the clay has been swirled more seems to make a big difference, particularly close to the center; working the base to relieve the stretch imparted by opening, seems to make a big difference. My guess, the cracks are along a seam imparted in the clay prep, and/or a shear imparted in the opening. Much as I'd like to conduct some serious and somewhat thorough testing, base cracks aren't at the top of my list! I'd like to think that wetter clay would be more prone to cracking, as it has further to shrink down that drier clay. On the other hand, wetter clay moves more easily, and drier clay is (err, may be) more prone to shearing*. I haven't done thorough testing to try to prove that clay prep makes a difference - my clay prep, that is - I do believe it makes a difference though**. I'm prepping each clay ball. It's a habit now. Contact with the wedging surface dries the clay, so I rotate the ball ninety degrees, several times, hence the outside is folded in, and in, and in. I believe that continuing the spiral imparted on the wedging board is helpful, so I tip the clay ball up on its right side (I throw clockwise) and roll it around some to seal the bottom afore stashing (I keep the prepped clay balls in a plastic bin so they don't dry out as much). Inconsistency in the clay will reveal itself; this is almost certainly true. *Once the clay has been pushed to the point where there's some tearing, the tear won't heal - it will "be back" again. Dryer clay can be worked longer afore it gets too wet and floppy, however, it also takes more time and force to move it. **The testing I have done: I prepared clay balls for classmates who were struggling to center and throw. The majority (by far) had a better experience! Perhaps due to two factors, a) more consistent, for any dry bits, bubbles, chunks, et cetera disrupt the flow of the clay, which leads to wonky wobbling frustration, and b) maybe, maybe the swirl imparted via wedging gets the clay moving in the "right" (or left) direction? However, maybe my classmates were just more focused, idk.

Good question! I've four slabs (made with a rectangular cake pan); light clays on one side, all others - red, brown, buff - on the other side. Both sides seem to dry the clay well. I'm setting the slabs on pieces of 1"x1" so air can circulate underneath, for once the plaster has absorbed enough water to be near saturation, evaporation from the surfaces of the plaster is (err, could be) more important in speeding things along. Indeed, the 1"x1" edges against the plaster get rather wet! Between reclaims, I'm setting the (wiped clean) slabs on their shelf with the 1"x1"s underneath and between, so they can thoroughly dry. I'm seeing the plaster (my slabs are near 2" thick) holds enough moisture to start mold underneath and between... It was taking several days for the plaster to thoroughly dry (we've since moved to a warmer and dryer climate!).

Hi AI, Welcome to the Forum! For still damp clay, burnishing could help. Will the sphere be glazed? added: cover with very fine clay slurry, then burnish Terra Sigilatta (digitalfire.com)

Good question Peter. Google returns a link to an archived post, it's here in the Forum. I'm seeing there are archived threads going back to 2010 or so. I'm not sure why the Forum's search function isn't getting it - it may be that the search function only looks at open threads? ...that's what I'm finding, looks like the Forum's search function does not look at "archived" threads - threads that are closed to further comment. a) having picked at random a thread that is closed to more comments, selected what may be a unique string, no hits, the Forum search does not find it; enter the same string in Google (quoted), plus CeramicArtsDaily, bingo, found it, top hit. b) from there, picking at random an older thread that is not closed to more comments, select what may be a unique string, search, easy find, the Forum's search finds it.

Hi Helzb3th, Welcome to the Forum. Condolences on your loss. Looks like that large lid could be held in place with a rubber band (or three)? We've used Museum Putty (and Museum Wax, a similar product) to hold narrow and tall works securely - it really sticks, but also peels away easily, even after considerable time. HD is carrying a product now called "Quake Hold" - perhaps roll a thin cylinder to form into a fillet, holding the lid in place all along the joint, all around. And the rubber bands too. That said, we shipped Mom in the urn (across the US, to join Dad), but for the trip, in a plastic bag, secured with a tie wrap, within the urn. Good thing, for the recommended shipper lost the parcel, and also dropped/crushed the parcel, which compromised the urn. The bag held o.k.

Glazenerd (a frequent contributor to the Forum) may have some suggestions.

"Oh yes, pass for most of us, sending around with strangers making clay pots, no thank you" "What's fascinating is the types of items fellow students make. ... Time, imagination and a willingness to fail - none of us cares if we make something ugly or lame - have freed us to create. It's an exhilarating experience."

Good question! Perhaps some glaze experts will have something to say about your recipe's gloss/matte behavior. I'd noticed that top shelf (my old kiln, given away; now waiting on setting up new Studio and, eventually, a new kiln) would have glossier finishes, so I started doing a controlled cool to 1850F, then shut down the powered kiln vent and heat at the same time. As for color, for sure my glazes will sometimes pick up fuming from neighboring pots. The amount of heat work, thickness of the glaze, cooling rate, any underglazes, and the clay all influence color as well.

Times allows limited (ten?) article reads per month for non-subcribers... Pottery Workshops Fill Up as People Travel to Connect Over Clay - The New York Times (nytimes.com) Interesting read, e.g. “Clay is the opposite of the cellphone,” Be sure to check the comments as well. As much as I truly enjoyed being in a community Studio*, the dust and artificial scents (hair products, washing solution, dryer sheets, cologne, perfume, oooh the et cetera) pose a looming ...barrier. *On arrival (always waay early), a slow tour of all the cubbies, the drying cupboard, glaze racks, everything! As the semester moves ahead, so does everyone's work. As the other students arrive, visiting and banter. Each hour, a new selection of music (when the instructor isn't lecturing). Watching how each person works a bit differently! Added: another Times article Can Old-World Horezu Pottery Survive Modern Tastes? - The New York Times (nytimes.com)

Could be the cooling rate? Faster cool, more gloss; slower cool, more matte. The tiny kiln almost certainly cools down faster - more surface area to volume (and mass). While waiting on more replies, please post the glaze recipe.

Hi Nav, Welcome to the Forum! I've not found any drawings/specs on Alsager wheels. You might try contacting Potterycrafts, per this archived thread: Alsager parts - Equipment Use and Repair - Ceramic Arts Daily Community https://www.potterycrafts.co.uk

Good points! The entire home is raised foundation (crawl space underneath) on a steep lot. The garage and veranda/patio are the most reinforced areas - cement slabs.

If/when firing unattended, setting the timer to expire shortly after peak temperature is reached could be important! Keep notes - size of the load (in weight), including furniture (shelves and posts); hours and minutes to target temperature; cone packs results.

My partner has (and is) supportive of my activities, and vice versa. She knew there'd be a gap to fill once retirement became a reality; maybe family, friends, reading, home projects, biking, hiking, fishing, swimming, and volunteering wouldn't be enough. This topic surely got me thinking about all the interests and activities my partner has supported over the years... Any road, specifically, she allows time and space for my exploration in ceramics, expresses a more than reasonable amount of interest, and leverages the supply of (potential) gifts for family and friends. She uses wares daily and resists my attempts to clear out "bad" ware to the point that I'm much more selective now when culling what cannot be given away (much less sold) to be maybe kept for our own use, drilled to become a succulent planter, or broken. If to be drilled or broken, it has to happen now! Thanks for sharing, hope there's more responses afore this thread slips down into the archives...

Hi Erin, Welcome to the Forum! Mighty Mud Mixer (Knoxville, TN) might be able to help you. They have several commercial glaze lines, recipes they mix, and they do custom orders which they can ship dry.

Seconding Min's point(s) on clays - for functional ware, firing to vitrification* is a worthy goal. Hence, the heat work required to vitrify the clay drives the firing schedule, imo. However, I'd guess that it's certainly possible to find a clay that behaves well when fired to 1250 C; also, some clays can tolerate a bit of over firing better than others... Looks like Bath Potters offers a lot of clays! They have a page that provides details on all their clays, including vitrification range, et cetera... Still, I'd rather pick the clay or clays I want to work with, then adjust the firing, over the other way around (choosing clays to fit my firing schedule). For food contact (the inside part), glossy glaze is easier to clean. A glossy glaze doesn't hide defects (e.g. crazing, fizzy bubbles, etc.) like a matte glaze does, and can be very durable, also mark resistant. ...back from a nice long early Summer** bike ride. While out there, was recalling where I'd looked for recipes, when starting out (just over five years ago). This Forum digitalfire.com (navigate to recipes from link, below) John Hesselberth's FrogpondPottery.com*** Susan Peterson's book The Craft and Art of Clay Lakeside Pottery's website includes some glaze recipes**** Another book I'm not remembering just now, will look for it ...not finding it, will try again later Bill van Gilder's book (I use two or three from his book) Wheel-Thrown Pottery I was looking for recipes from a known source, where there are usage and/or testing notes included (pictures are nice too) A well behaved clear liner (there's enough white in mine to show over dark clays) glaze took some time, testing, trial, start-overs, some help, and then aaah. It has significant MgO, small amounts of Sodium and Potassium, a dose of Lithium (a little bit makes a difference!), and there's Boron - it melts well - for I work cone 5/6; there's enough Silica and Alumina to make a tough glaze that doesn't run or sag much. *Vitrification (digitalfire.com) **It's warm enough, I'm calling it Summer! ***archived here Tested Glazes | Frog Pond Pottery (archive.org) ****Cone 6 Glaze Recipes | Great Mid Range Pottery Glazes (lakesidepottery.com)

Hi Julia, Welcome to the Forum! Good question. If the cones you are using in the sitter are from the same box (as previous successful firings), likely the problem isn't the cone. That said, setting up a cone (or a cone pack) on each shelf gives you more feedback - what the heat work was on each shelf. Was the kiln on for about the same time it usually takes to bend a cone 6 in the sitter? How did the ware come out; were the glazes fully melted? Do you think the ware was overfired? I fired a sitter kiln for just over four years. I bought a pyrometer, watched the readout closely, and took detailed notes. I also set cones on each shelf, where the middle shelf's cones could be seen from the peep, just in case I needed to check! My next kiln will have a controller, still, I'll be watching the pyrometer read out, placing cone packs on each shelf, and keeping notes. Once familiar with the kiln, I won't be checking the cone packs while firing. The first few firings, however, I'll be checking the cone packs while firing! Be sure to use proper kiln glasses to protect against harmful rays and any flying bits, very important.

Hi Darla, Welcome to the Forum! Gigi hasn't been on the Forum for quite some time; you might send them a message (go to their Profile page, select the Message button). Isn't the Model 15 a cone drive? Looks like The Ceramic Shop has some parts for the Model 15, including the drive ring Wheel Parts : Brent - The Ceramic Shop Aardvark Clay has "orange belt" Aardvark Clays Please post an update on your findings?