Callie Beller Diesel

I don’t know about other lustres, but gold and white gold are made of those actual materials, and don’t tarnish. Some raku glazes that contain a lot of copper can be prone to reoxidizing over time. Usually folks will coat pieces like that with spray varnish or similar. I think it could work for Palladium.

If we’re taking bets, I call iron in the water being the culprit. It’s the one constant variable across all OP’s tests so far. Very interested to see how the distilled water variation turns out.

@AndreaK I think you’re probably relatively local to me, so I assume we’re talking plainsman clay at least. Does the studio you’re looking at do commercial or homebrew glazes, and what kind of work are you thinking you’d like to make?

Ferric chloride isn’t necessary by any means. I haven’t done a whole lot of pit firing, but I did a couple back in college. You can get some lovely variations with terra sig on its own, especially if you’ve got a light and a dark colour to create contrast with.

Probably. Part of the fun of working with found materials is the variability. Sometimes close enough is all that’s needed.

I use a talisman at work, and while it’s great for 10 gallon batches of glaze, it would be wildly impractical in my home studio. The cleanup of the brushes is a pain. I have a smaller sieve that sits in a 5 gallon pail at home, and I use a large round sash brush to push the glaze through. It works pretty fast and cleans up very easily.

Yes. Yes this will affect things. If your kiln is hottest on the bottom and you’ve packed it tightly, but your ware still isn’t getting the heat, the bottom is probably packed too tightly. You may also be going a bit too fast through the middle parts of that firing. 120 C is a really fast rate of climb. And yes, it’s not unusual for a bisque to go for 10-12 hours. Keep in mind the elements aren’t on at full power the whole time. If you’ve got the touchscreen, check out the diagnostics in the last firing. It’ll tell you what your energy usage is. Re: the density affecting the heat: Electric kilns are sometimes programmed to emit more heat on the bottom elements, because heat rises, and they’re trying to avoid cool spots in the bottom of the kiln. They’re assuming people pack it evenly, and they don’t expect consumers to have to compensate their loading habits on a new kiln. If the bottom part of the kiln is packed particularly densely, especially compared to the other shelves, the heat may not have time to penetrate all the way through to the middle of the bottom layer. If the cones aren’t bending on that bottom shelf with a 20 minute soak at the end, that bottom layer and even the middle is probably playing catchup to even hit cone 09. Try slowing your second segment to 90 or 100 degrees C, aiming for the proper cone 08 temperature, and packing the kiln more evenly.

Hi and welcome! It is possible to get durable ware at earthenware, midfire and high fire temperatures, but there are different considerations at each of those points. I won’t use the term food safe, because it’s a bit of a misnomer, and legally only covers whether or not the glaze has cadmium or lead in it. When we talk about glaze durability, we want to make sure that the clay is fired to a point where it would have less than 1% absorbion, the glaze doesn’t leach anything, isn’t crazed, resists both scratching and cutlery marking, and is easy to clean. With earthenware in particular, you have to be mindful of glaze fit, because earthenware clay remains porous when fired to maturity, and many will glaze the piece all over, and use kiln stilts instead of leaving a bare foot. You have to be extra mindful of your glaze chemistry, because the low temperatures tend to mean the fun, pretty glazes can sometimes be prone to scratching because they’re lower in silica and alumina.

If it’s one of those ones from Amazon, you may be out of luck entirely. They don’t have a good reputation for replacement parts or service. There is, however, and old trick you can use that may save you some searching. Place a sponge against the edge of the wheel head, and it’ll absorb most of the slip that flies off the wheel as you throw.

I get mine about 10 boxes at a time and stack it outside the studio door. I go through it at a rate that it doesn't have time to dry out. But I also have the luxury of living in the same town where I buy my clay.

Juried exhibitions or invitationals through galleries have never netted me any sales. They can be a nice ego rub, which has its own value, but that value isn’t monetary IME. Juried fairs or markets however, are a good thing. Juries can help put together a crowd of compatible artists and quality of work, which helps get it in front of people who are interested in such things.

Birdie Boone, Shprixieland Studios, Naomi Clement and Sarah Pike are 4 artists I can think of off the top of my hand who slab build and leave exposed seams. All have WILDLY different work from each other. Google for comparison: you’ll feel better. Unless your work also has a lot of other design features in common with the image you linked, the person who says you’re copying is out to lunch.

I wish I could remember where this piece was installed, or who made it, but an artist made a whole bunch of thinly trimmed porcelain bowls, and floated them in a pool of water with a gentle current running through it. The bowls rang and sounded like wind chimes when they bumped into each other. It was incredibly soothing. My initial inclination for question three is to say that I’d prefer to interact with a piece rather than have a constant sound, but I think that subtle environmental interactions could count towards that.

Toxicity is a whole entire subject by itself. Mostly we have to start with definitions to help clarify. Tl;dr, yes you can put this glaze on the outside of a pot and it will be fine. It’s not touching food. It melts fine at cone 6, it’s just a “soft” glaze. When a raw material is labelled toxic, that means it’s toxic in its current form. Once you put a material into a glaze with other materials and fire it, it becomes another material entirely, with different properties. If you’re using a commericallly mixed glaze that is labelled non-toxic, that means it’s not toxic in the unfired state. (It’s probably not toxic in the fired state either, but you’d have to test it to confirm, and manufacturers can’t say that it is for sure under all circumstances without legal problems. People do weird and unexpected things.) When we’re talking about glazes, most often the finished glaze is more safe than, say, raw lithium. So potters should be concerned about their own health and safety first, and the end user second. Materials like lithium can be handled safely with sensible studio hygiene practices, and can be beneficial in a lot of good glazes. When knowledgeable glaze chemists talk about food safety, we aren’t talking about whether a glaze will leach Bad Things (TM) into food. This is a very infrequent scenario outside of lead use, and lead hasn’t been used in most handmade pottery for decades now. But we are thinking about craftsmanship and durability. We’re asking questions like Does this glaze have flaws like crazing or pinholing, that can affect structural integrity or possibly harbour bacteria? Does this glaze scratch, or does it cutlery mark? Does it stain easily? Is it easy to clean? If those problems are solved, leaching is usually a non-issue. Re the silica question: You need 3 types of components in the right proportions in a base glaze for durability: silica to form glass, alumina for strength and to make it not run too badly, and different metals that make silica and alumina melt at much lower temperatures than they do by themselves (fluxes). Without enough silica or alumina, or if those things are in the wrong proportions, the glaze may react to acids found in many drinks, bases like in dishwasher detergent, or may scratch or cutlery mark. SCM doesn’t supply enough silica for durability, but the strontium is also a problem. Within the flux category, there’s a bunch of stuff that’s a good idea to use in combination, because each material has beneficial and undesirable properties, and mixing them can bring out the best (or sometimes worst) of both worlds. For example, sodium is a strong flux, which is needed to bring down the melting temperature of silica and alumina, and is in most glazes. However, it tends to make glazes craze when by itself. But if you mix it with calcium (or barium or strontium or lithium and a few others), you can still get the melting, but less crazing. The calcium/magnesium/strontium etc group of fluxes also give you different colour responses, or can help create matte effects if the proportions are high enough. One of the drawbacks of using strontium or barium though is that neither is very high on the Moh hardness scale, so if you use too much of it, the resulting glaze can be prone to scratching, staining or other flaws. But it helps create that really cool matte surface because it promotes crystallization, so sometimes creative folks make trade offs.

Also, were the blistered pots in the same part of the kiln as the non-blistered ones, or were they in different parts of the kiln? If the blistered ones were on the same shelf, can you determine if that shelf hotter or cooler than the others? Were there factors like pack density at work that might have created a bit of a heat sink?