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  1. Today
  2. Thermocouple K15 DS - 2A is most likely the weak link . I Think Bills advice is spot on above. Replace the thermocouple 1st.
  3. I have a pot that has been fired twice. I would like to use red iron oxide to emphasise the textures and designs, but I believe if it applied to m fired pieces it won’t adhere. Rather than have it fired for a third time I wondered if there is a way to seal it once applied.
  4. Glaze: a glassy matrix generally composed of clay, Feldspar, silica, flux and colorants Oxides: specifically natural mineral colorants, carbonates are also rolled into this category. Iron, cobalt, copper, manganese, chrome, tin, titanium, zirconium and others will impart a very strong coloration to clay, slip and glaze. Stains: stains are standardized "fritted" mixtures of oxides which are reliably and consistently the same. These are an important element to commercial pottery as the colors do not shift. With oxide colorants, since they're mined minerals, they can vary in color drastically from batch to batch. Fritted means they're fired into a glassy matrix and then reground into a fine dust. With stains generally WYSIWYG, whereas an oxide can appear black but fire to blue. Or appear brown and fire to yellow. Hope that helps. Oxides (in this case) and stains are often just colorants that are used in formulating glazes, but are sometimes used as a strong colorant on the clay body, or over or under glazes.
  5. julia, you have the beginnings of a great collection of pots. if you are anything like the potters i know, you will end up with a large collection of every shape and color someday.
  6. chilly, it seems that there is a difference in terminology across that ocean, not only in the UK but on the continent as well. wondering how the difference can be explained so we all can understand. the polish pottery factories use color applied with sponges cut in various shapes. their translation of what is being used is not quite clear to me. seth cardew demonstrated his use of color at a workshop here and when he ran out of blue, he asked for some cobalt (not specifically carbonate or oxide) and mixed it with water to make his beautiful birds. just a wash, to my way of thinking. hope someone can clarify it all, thanks for the question, bont.
  7. jude, what is it you are trying to achieve with the red iron oxide?
  8. Yesterday
  9. Large cones melt as noted above at different temps than small cones. Toy will have to learn the differences if you want to use small cones. The norm is use large cones only for manual viewing. small cones for kiln sitters.
  10. Going back to this, I don't know how big your kiln is or if you were using a kiln sitter or if it's a single or 2 or 3 zone computer controlled kiln so this might be a bit of a ramble. I'm guessing it's a kiln with a kiln sitter? If so then the cone in the sitter will be approx 1/2 way up the height of the kiln. When firing a mostly empty kiln it's not going to fire the same as if it was packed, I would expect the bottom to be cooler than the cone in the sitter. Same deal for a single zone kiln with a controller. 2 or 3 zone kiln should be a bit more even but again being mostly empty will have an effect on the firing.
  11. 9 degrees isn't much, maybe I had them buried too deep, 15/16ths exposed is hard to eyeball on these little guys haha
  12. From Orton re small cones: "Small Cones can also be used on the kiln shelf as miniature witness cones when space is limited. They require mounting in cone holders or plaques at an 8° angle and a width of 15/16 of the cone exposed above the cone holder. Small Cones used on the kiln shelf deform at about 9°F before Large or Self-Supporting Cones of the same number."
  13. I find the self-supporting cones more convenient since I don't have to deal with making a "cone pack"...
  14. I mist the piece, mist a container (I've an assortment of containers to invert and cover work with, having sworn off plastic for wet work), then enclose the piece. For a too dry piece, a piece of wet sponge in there (next to, not on) helps. Also helps to be patient!
  15. I'm interested in what others are seeing, large cones vs. the small ones. The big ones cost more, however, easier to use and see. The small ones are cheaper, harder to use and see, however, they can be fitted to a kiln sitter - double duty! The bars are more precise for the sitter (the sitter's trip point is too easily influenced by the taper of the cone, yes?), but almost useless for anything else. I'm cheap, so will stick to the smaller cones; I've some big ones that previous kiln owner threw into the deal. Repeatable, that's important to me - still lots of learning out ahead! A bit overfired - where cone 6 has bent over far enough to touch toes - causes problems with two of my glazes...
  16. I usually toss them in the plaster wetbox upside down for a few days and it evens out.
  17. Worth a try Hulk. I'll grab some larger ones and run some tests side by side and see if they slump differently.
  18. I set them up as witness cones like that, along with cone 6 self-supporting ones and they were showing at least half a cone less compared. I still have basically 6 boxes of mini cones that I figured I can't use anymore, so if you're saying they work I'll give them another shot
  19. Thanks! Looks like I'm off to buy some larger cones.
  20. Hi M! Good question. I'm still assuming the small cones indicate same as the bigger ones, if set up per manufacturer's instructions. I make up "cone packs" (guide, target, guard - one each) using a strip of clay for each one, where each cone is set to the required angle; probably best to make them up well ahead of time, so the clay is thoroughly dry. I've a good idea how damp the clay can be and not blow up, haha, guess why. A cone pack on each shelf, along with the sitter's cone, gives an idea how uniform the heating was. My kiln runs cool at the top shelf and a bit cooler at the bottom, which we mitigate by staggering the half shelves such that the cooler spot "sees" more element, also by loading a bit less densely... "They don't slump the same way." Interesting! I'm seeing the small and large cones reflect heat work identically.
  21. They don't slump the same way. I tried them after I ditched my sitter for a computer and they weren't even close. Maybe not enough mass to carry itself down when it gets hot, I think they need the pressure from the kiln sitter to bend
  22. Mea Rhee, from this forum, has a video for rent that addresses this issue, as well. Check out the videos on goodelephantpottery.com and learnpottery.com As with most things clay related, there are a large number of solutions and work arounds! Love your form @CactusPots Roberta
  23. If you fire it hotter than you think it might survive, put a sheet of known high-fire clay under it. It can make a mess of a kiln shelf otherwise. (Or in my kiln, of the floor!)
  24. My opinion, others will have their own opinion: Glaze - makes a finished surface, may include colour or be clear, usually glossy, most dinnerware is glazed Stain - used to colour glaze or underglaze Underglaze - purely colour, doesn't usually give a finished surface, not usually glossy Oxide - metalic substance, also used to colour glaze and underglaze, can be used like an underglaze or on it's own. They're all words that are used interchangeably by both knowledgeable potters and TV presenters. Remember that "throwdown" is entertainment not educational.
  25. Hello! Have a quick question on using kiln sitter cones as witness cones. Got me first kiln over the weekend and did a small bisque fire to test it with about 5 mugs with different clay bodies in the bottom of the kiln (on a shelf 1/2 inch off floor). I was firing to 04 and got a stand to hold the small kiln sitter sized cones upright to use as a witness. I got only a slight lean out of the witness cone on the shelf with the mugs. When doing research I realized in all the images I was looking at, a larger cone or self supporting cone was used. Do the smaller kiln sitter cones slump over like a larger cone when used as a witness cone? Or did the bottom of the kiln really not fire to the right temp?
  26. You have to seal it, it will wash off or stain your hands when you touch it. Even refired you can have some stain rub off if you don't have some flux in the stain. Denice
  27. Hello, I've been wondering for a while now about the differences between glaze, oxides and stains. I've googled the question many times but never got an answer. I'm watching a show, The Great Pottery Throwdown, and when the bisque stuff are ready to fire, the MC would say "Over here, we've got the oxides and the glazes". So yeah, how are they different? Thanks.
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