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Tyler Miller

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  1. If this is paint, add calcium carbonate (whiting) and use a UV whitener additive to take off the yellow edge. Glaze—zirconia products? for a whitener, they’re pretty cheap. But as Neil says, glaze is cheap.
  2. Tyler Miller

    cadmium red

    VivK, I realize that strong statements that go against your expected reply, may seem jarring. Since it seems to be the expectation that Cadmium is fine, I apologize for causing you cognitive dissonance. My statement was made under the impression that you had begun to research and had maybe poked around the forum to see that acceptable leach limits, potential for leaching, and potential for harm were set a little closer together than for others. Let’s unpack that declaration (if not hysteration): Sputty et al. have supplied limits to cadmium consumption (links above) et al. (me) provided detailed reviews of evidence and cadmium’s toxico kinetics (links above) and then I posted some studies on leaching a while back that mention cadmium, like this one: http://www.mdpi.com/1422-0067/12/4/2336/htm or this one: https://www.sciencedirect.com/science/article/pii/S0048969797002441 Taken together, it shows that it’s pretty easy to poison someone (at least chronically), with poorly formulated cadmium glaze.
  3. Tyler Miller

    cadmium red

    I hope this helps: A world health organization report on Cadmium: http://www.who.int/ifcs/documents/forums/forum5/nmr_cadmium.pdf A review of lit from PubMed (if behind paywall, use Uni library for access): https://www.ncbi.nlm.nih.gov/m/pubmed/11904357/ Another review detailing toxic effects with discussion on treatment (excerpt below): https://www.hindawi.com/journals/tswj/2013/394652/ “There is no agreement in the literature regarding treatment of Cd toxicity. Human studies are few and anecdotal. While clinical protocols exist for the use of EDTA, DMPS, and DMSA [101–104], they rely for the most part on clinical experience and on in vitro and animal studies [105, 106]. EDTA is the agent most widely accepted for clinical use. While it may seem axiomatic that reduction of body Cd burden would decrease its toxic effects, not all authorities agree that active measures beyond avoidance are indicated, at least for acute poisoning, where concern exists that chelation may aggravate damage to the kidney tubules [107, 108]. For chronic exposures, however, there is considerable evidence of chelation’s clinical efficacy, in humans and in experimental animals. Several chelators have been used. Clinically available c”
  4. Tyler Miller

    cadmium red

    Cadmium is pretty bad news. There are two kinds of hazards a studio potter has to be aware of—poisoning yourself/studio mates and poisoning your consumer. Studio hazards are many and we work with lots of acutely toxic and chronically toxic substances. Dust control, work wet, etc etc. covers all that. Cadmium stains are now available encapsulated, which should reduce studio risk. Talking to your doctor is also a good idea, there are a whole protocol of tests for cadmium levels if you’re concerned. Cadmium’s real issue comes from the fact that it can poison your end user. Pretty easily. That’s what the leaching laws are about. a poorly formulated cadmium glaze is a lot higher stakes than a poorly formulated copper or cobalt glaze. Gettig cadmium out of the body is a lot harder than most other metals. Chelation doesn’t really work. Not saying don’t use it. Just be extra safe, and test your stuff if your plan on selling it.
  5. I think the answer is application dependent.
  6. Tyler Miller

    Glaze Defect

    I think Neil has the right idea. I think this has to do with glaze application to green ware. It was maybe applied too thickly?
  7. Tyler Miller

    Beach sand instead of grog?

    @yappystudent What I mean is only use sand you can source from the same place every time you need more. That way you’re not back at square one every time you run out. Essentially, I’m suggesting a way to remove a variable. The fewer the variables, the better your understanding of how it works as a glaze/clay body ingredient. Also, while I think of it, track down Jonathan Walberg of J pottery in Wisconsin. Beach sand from Lake Superior is in almost all his work.
  8. Tyler Miller

    Beach sand instead of grog?

    If I may make a suggestion, use ingredients that have a definite provenance in your work. In doing so, try to work around the characteristics of a material to include it in your work, OR, pick an effect and gear a material toward that effect. But don’t do both at the same time. Take the time to figure out what that beach sand does. It may not work in a body, but your might find that when ball milled it produces an OK glaze component. If you’re after that groggy effect, feldspathic chicken grit or granite fines from a local quarry will work better. Also, be aware of local laws and policies concerning aggregate resource harvest. In Ontario you need a license to dig sand, clay, and gravel for use, when south of the French and Mattawa rivers. Quarries are a good work around—they’re licensed and (sometimes), know a bit about what they’re digging. Crushed, quarried sand is brutal on the hands. Gives great green strength, though.
  9. Tyler Miller

    Need a translation of a glaze name

    “sanka” can mean oxidation? Could that be it?
  10. Tyler Miller

    Need a translation of a glaze name

    Ruri means lapis lazuli. Can’t help with sanga.
  11. Tyler Miller

    Narrowing it down_things to make

    Engage in your clay work fully and completely when you do it. Learn to think critically about form, function, meaning, and expression in your work. What you’ll find is that as you engage and think and work is that your artistic values shake loose from the small decisions and your style comes from that. And you keep doing that, with a critical eye directed at yourself, you’ll find yourself with a style that’s growing and evolving. Personally, I’ve found the question “what should I make?” bogs me down and stifles my drive. It’s a valid question, and important if you want to sell your work. But it feels like pressure, and I’ve found a lot more satisfaction constantly asking “Can I make this?” or “What would happen if...?” and then weeding out what I don’t like. Find what makes you happy to produce.
  12. There’s no way there’s glass formation at that temperature. There are few minerals that will self glaze at campfire temps, but otherwise it’s not happening. Also, hematite doesn’t melt at 950 C. Hematite is Iron (III) oxide, which melts at—it doesn’t. It decomposes—at a much higher temp. A fact not insignificant to ceramics. (oilspot) It does, however form solid solutions with minerals of similar crystal structure. Solid solutions can be a tough concept to grasp, but it doesn’t mean the material melts at that point, just that it goes into solution at that point. I’m in doubt that an ilmenite-hematite solution’s at work here.
  13. Two things prevent what you’re saying from being “Occam’s solution.” 1) I’m pretty sure the potassium salts present aren’t really reactive in a meaningful way. My reason for saying this is because I’ve never heard of them being used as colourants. I’ve also not really heard of a proper vitrified surface from pit fired wares with salt. In fact, I’ve heard they can effloresce under the right circumstances as the pots age. Leaving aside the fact that salt doesn’t produce the colours we’re talking about. If the effect were as you say, we wouldn’t have to stretch for parallel processes like raku (which is still rather hotter) and industrial chem. In short, it would be a repeatable phenomenon. and a known one, since pit fires are common. 2) The established method for getting metallic streaks on ware is fuming galvanized metal. Eduardo Lazo even recommends galvanized chicken wire as something that can acheive this very effect. Which is simpler? An unproven potential practice, based on analogy? Or the established practice of x- material produces y result? Now, the OP has said there was no metal in the pit, so that means my theory is discounted. The only way we can know is if it’s tested.
  14. I feel the need to invoke Occam’s razor here. The theories are getting a little convoluted. Salt (NaCl) and soda aren’t likely produce metallic effects. Blacks, greens, browns, greys, and oranges, are more in its wheelhouse—and that’s when dealing with salt/soda soaked string/cloth/straw wrapped around a piece. I think the best course of action, if you’re worried about what it is, is to get it tested.
  15. Maks, Did your firewood have any galvanized nails or fencing staples in it? Or maybe some scrap metal? I used to get metallic-grey streaks when I fire raku sometimes because the cans I’d use were zinc lined.
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