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Tyler Miller

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  1. Gold’s pretty inert stuff. The chems used to suspend the gold for application are pretty horrific, and the gasses they release during firing are bad, but the gold itself is harmless. There’s nothing in the body to interact with the gold. Passes straight through you. Luxury foods are regularly gilded. Silver isn’t harmless, but it’s pretty low on the toxicity level. In high enough doses for long enough, you’ll turn silver yourself, a condition called argyria. Link: https://en.wikipedia.org/wiki/Argyria Edit: I shoukd say, the compounds used to make “silver” the colour are not always so safe. Bismuth, manganese, etc.—esp in raku.
  2. Lepidolite

    Neil, they have to include conditions under which the materiak becomes hazardous. At least, in Ontario they must, we updated OHSA and WHMIS in the last year.
  3. Lepidolite

    Pres, you’ve provided an excellent object lesson here. This is an example of low grade safety information. 1). It does not provide information as to how to evaluate risk. The section on lepidolite does not say how it is highly toxic via respiration, nor does it really explain how that risk should be mitigated in ways different from other materials. 2) It was clearly written by someone outside the field of health and safety. In the dust control section, it says use a hepa filter mask. Hepa stands for high efficiency particulate—that would be great, except there’s no such thing—at least, no single such thing. There are P-100 filters, N-95, etc. but I can’t find hepa as a meaningful term when I google “hepa filter mask.”. In fact, the first result I get is for a half face respirator for organic chemicals. Glazenerd provides a similar object lesson with his MSD sheet. It’s missing many key points of data which could be important to health and safety. The temp of decomposition and thermal stability being the important ones—since we know that the decomposition of lepidolite is a key feature of its function as a flux. Here is a detailed links into the exposure levels of fluorine gas: https://www.ncbi.nlm.nih.gov/books/NBK220011/ And hydrogen fluoride: https://www.ncbi.nlm.nih.gov/books/NBK207733/#!po=0.287356 I would like to take note of Tony Hansen’s comments on fluorine and what it does to windows: “Good kiln ventilation is essential. Over a period of time, fluorine gas will even etch windows in the kiln area until they are opaque like frosted glass. This is ample evidence of its presence.” Link: https://digitalfire.com/4sight/hazards/ceramic_hazard_fluorine_gas_108.html I’m going to recommend, if you want to play with the dangerous stuff, an up to date copy of something like Sax’s Dangerous Properties of Industrial Materials (a three vol. work) be on your bookshelf. Also, a word about lepidolite and its availability. It’s generally unavailable as an ore because its mined in countries the US and Canada tend to avoid doing business with. I’ll let you do the research into why that may be and form your own ethical/political considerations about the material’s use. This is not the place for world politics.
  4. Lepidolite

    Yeah, no. 1) I have no arresting authority. 2) commenting that someone is entering a grey area, who should know better, is not arresting someone for a potential crime, but it is commenting on the fact that someone is entering a grey area when they should know better. And that type of comment is, to my original point, the appropriate for a mod hence my comment I was taking on his role.
  5. Lepidolite

    @neilestrick Let’s leave aside the forum mod’s general responsibility for a second and instead look at the specific safety responsibility. Fluorine gas, and hydrofluoric acid are two of the most reactive substances on the planet. Fluorine compounds are so reactive, in fact, they can oxidize oxygen. The discovery of the element killed or maimed well over 20 men. This is not silica, or even lead. It’s a whole other level. While it is true that at normal temps lepidolite is safe and stable at room temp, it is not during firing. Let’s say someone asked for a source for yellowcake uranium (the compounds of which have indeed been used as glaze pigments). Or ammonium nitrate, or mercury fulminate. Suddenly the scope if safety shifts, doesn’t it. Is it ethical to post a source for anfo or yellowcake? Is it ethical for a publishing platform to NOT immediately comment on that product? This is the level of safety we’re talking. Not chronic injury; sudden permanent blindness, horrific chemical burns. Is it ethical for a mod not to comment when they (should) know the risks inherent in using that product, being in possession of it. People DO use these products in glazes, but they also use uranium and other dangerous exotics and that’s OK, but a discussion on it needs to be heavily heavily disclaimed, and the ones who moderate that discussion shoukd do the disclaiming if they can. I know things are usually cordial here, but I stand by my comments and I would feel negligent were I to not say something. honestas probitasque per se semper desiderandae. For me, at any rate. It was the punchline of the joke, which is why it was coming dangerously close. All that needed to happen is “You serious? I’d pay that” and suddenly it’s actual business. I didn’t say there was a ruke break, but that it was dancing a line.
  6. Lepidolite

    Neil, it probably should not be his job. But I also feel it’s not a complete discussion without mention of the fact that lepidolite produces fluorine on firing. That’s a big deal. I’ve said I don’t think lead glaze recipes should be published, and you’ve said it was a poor ideal for me to say copper was mostly safe in glazes. Your argument was one of liability. And to some extent you have a point, and I changed my post to reflect that point. Here’s my point. It is a phenomenon in the information age that publishers are held responsible for content. It’s why some academic publishers won’t publish certain research. It is also true that a forum is a publication platform, and as such, the representatives of that platform have. responsibility to police safety and adequately disclaim posts. (This is unfortunate.) Lest the forum run into legal trouble when little Timmy decides he wants to watch his lepidolite glaze fire. It is also the case that John has policed safety in the past. As for the second point. I stand by it. When someone asks for a source for a product and three people say they have that product, that’s dangerously close to doing business, not talking business. I’m done now, okay? Actually, one last thing google “fluorine martyrs.” The isolation attempt killed or severely injured a lot of men.
  7. Lepidolite

    It has to be said, there is a 100% chance of the hazardous conditions detailed in the laguna fluorspar msds forming in a reduction firing. 1). Water is a product of hydrocarbon combustion. A necessity in reduction. 2). The temperature is elevated. 3) Amorphous silica is present. 4). Reducing agents are present. The violent reaction is what makes the pretty results. I’m not telling people not to use it, but fluorine compounds are not to be trifled with.
  8. Honestas probitasque per se desiderandae.

    1. Min

      Min

      Thank goodness for google translator, guessed at most of it. Good tenant to live by.

    2. Tyler Miller

      Tyler Miller

      It’s a paraphrase of Cicero, against the Epicureans.

  9. Lepidolite

    I’m going to go ahead and perform the role of the mod here, since that’s not being performed. 1) lepidolite’s Lithium is not tied up with oxygen, but with fluorine. You have to heat the stuff to dissociate the fluoride and get lithium oxide (not to mention the potash). This will accelerate kiln and person wear. There are stories on this very forum of health effects of fluoride in glazes. Its dust is also pretty bad news 2) This thread is coming dangerously close to breaking the talk business don’t do business rule.
  10. Making terra cotta bricks

    Mod's job, not mine.
  11. Making terra cotta bricks

    I would use bagged terracotta sculptural clay which should include grog. I would also make your bricks a little thinner than conventional store bought bricks. Commercial bricks are made and fired a little differently, which means they can get away with things we can't. Have a look at African fired bricks or Roman brickwork for ideas about how to make them in a more potter friendly way.
  12. Tony, The vast majority of trimming tools out there are for sculptors, not potters. Things like carving out an ear or getting the creases in an eye's crowsfeet just right are things that require a special angle or blade shape. But, even then, it comes down to what your gut says. There's no hard and fast purpose for any trimming tool. You can get by with just three or four, or may feel a set of fifty isn't enough. For reasons I can't explain, I will often trim two identical mugs with completely different tools just to get the same result. Buy some you think you can use and play with them. You'll get a feel for what you like and don't. Edit: A thought: If you really want to categorize their utility, do what repoussé/chasing artists do with their punches and categorize the trimming tools based on what kind of cut they make in clay. That will help you get a greater feel for their utility and purpose in your work.
  13. Drying Pots developing mold?

    Briana, Since the clay does hardpan, here's my theory based on my own personal experience. I throw a thixotropic (the more you touch it the softer/stickier it gets) cone 10 porcelain body that has given me similar residues on pots before. What it turned out to be in my case was feldspar. When this clay becomes slip, it doesn't like my hard water and settles out almost instantly. Big ol' hardpan in my throwing slip bowl of flint and feldspar, with the kaolin/ball clay still in suspension. It would settle out on my hands, and when I'd wipe them off, the feldspar/flint would be harder to get off. I had a thumbprint of the exact appearance of your "mold" show up on a mug as it was drying. Incidently, this clay body I used does effloresce a little soluble salt, but it's the tiniest amount and doesn't affect anything. The tl;dr answer: If it is mold, like everyone says, just do nothing. Won't hurt a thing. If it's what I say, a gentle wipe after trimming with a slightly damp sponge will remove the residue and shouldn't return after trimming (provided your boards and hands are clean).
  14. Drying Pots developing mold?

    I'm going to say it's probably not soluble salts because the pattern doesn't look like efflorescence. It looks to me like you set the "moldy piece" on something. Hence the ring shape, which is the portion of the piece which would be in direct contact with the board you set the piece on after throwing. Mold would grow more randomly, and salt would effloresce in a different pattern (and would likely be a problem for all, not some). My question: when throwing, does this clay like to settle out in the slip bucket, maybe forming a hardpan at the bottom?
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