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About mrcasey

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    As far as ceramics go, I'm interested almost exclusively in hand building slab pots for bonsai. I'm looking to create traditional forms with very simple geometries.

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  1. What is a good definition of centered clay? (I'm especially curious about Tyler's and Baymore's opinions) (1) What is the mathematical/physical definition of a centered piece of clay? and (2) Why does coning up and down center a piece of clay?
  2. A member of our community studio would like to mix up a batch of Patsy Green 2 from John Britt's mid fire book. The lithium concerns me as does the 4% copper. I don't have glaze software to look at the limits and I was wondering if somebody could run the numbers for me. Also, I'd be interested in anyone's opinion about the safety of the glaze. Neph Sy 44 Silica 18.9 Whiting 7.9 Kaolin 2.3 Dolomite 5.6 Gerstley Borate 12.8 Lithium Carbonate 4.8 Zinc Oxide 3.8 ------------------------------- Copper Carbonate 4 Bentonite 2
  3. Deflocculate Or Add Water?

    Isn't this backwards? If the glaze hard layers on the bottom, it needs flocculated.
  4. Deflocculate Or Add Water?

    I have no plans to mix up another batch of this stuff. I'd just like to fix this one as best I can and move on...
  5. Deflocculate Or Add Water?

    If I had it to do over again, I'd calcine 1/2 the kaolin and not add bentonite. I certainly wouldn't use this new sodium bentonite that makes gelfromhell. The reason I added the bentonite is because it says to in Britt's recipe. John Britt's 3M-4 Matte with 5% gray mason stain Custer Feldspar 6 % Silica 8 % Wollastonite 20 % Kaolin 40 % Frit 3134 12 % Talc 14 % : 100% Mouse Gray M. Stain 5% Bentonite 2 % The first s.g. measure was 1.5 which was crazy thick. It looked fine on a test tile but gave some of the other studio members some serious crawling issues. People asked that I thin it out. So I did. It crawled again, so I thinned it some more. I just kept adding water until I got down to an amazingly low s.g. of 1.25. At 1.25, the stuff is the thickness of heavy cream and still crawls. On top of all that, it flows a bit too much and becomes streaky. My new plan is to actually take some water out and then deflocculate with darvan 7. If that doesn't work, I'm stumped. I'm a little annoyed that my little 2" X 3" test tile didn't reveal any problems. TEST TILES SUCK!
  6. When a glaze is really thick, how does one know whether it needs more water or needs to be deflocculated?
  7. What is the error range on such a scale? 1/2 gram maybe?
  8. I broke the hydrometer so I'm using a 100 mL graduated cylinder and a Harbor Freight electric gram scale accurate to .1 gram.
  9. I'm going to make things a little more concrete. Matte Gray Glaze Custer Feldspar 6 % Silica 8 % Wollastonite 20 % Kaolin 40 % Frit 3134 12 % Talc 14 % : 100% Mouse Gray M. Stain 8 % Bentonite 2 % This stuff is the thickness of wet concrete. Today, I added water till I got down to a 1.25 specific gravity. It is still crazy thick - thicker than heavy cream. Can I just keep adding water? Should I deflocculate? Panama Blue Custer Feldspar 44.1 % Silica 15.8 % Whiting 2.6 % Kaolin 2.6 % Dolomite 7.7 % Strontium Carbonate 4.2 % Frit 3110 10.7 % Frit 3134 9.7 % Zinc Oxide 2.6 % : 100% Tin Oxide 2.6 % Copper Carbonate 1.75 % Bentonite 2 % I've chucked in 4% bentonite (that's a lot) and added a tablespoon of epsom salts to this glaze. It looks heavy as whipping cream, but it still gives me a thin covering, curtains badly, and dries crazy slowly. Should I just add more bentonite or epsom salt? The specific gravity is 1.46. That's about in the range for our cone 6 electric oxidation dipping glazes. If I take out any more water, I'm afraid I'll have to put it on with a putty knife. Any thoughts or suggestions?
  10. Recently we changed bentonites and our newly mixed glazes look way thicker than they used to even while I'm adding more water. The specific gravity measurements are a little lower than they used to be and the glazes look flocculated. Is it possible that a watered down glaze could run more, simply because it's over flocculated or had too much bentonite added? All of this seems very counterintuitive to me. I always kind of assumed that for a given mass of glaze material, adding water would thin the glaze and make it less likely to run. Taking out water would thicken it up and make it more likely to run. That is, if I drop the specific gravity, there's going to be more water, and less chance of the glaze running.
  11. We have some old brushing glazes in pint containers. The glazes haven't been used for almost 5 years. Some of the containers are almost full, but the glazes are as thick as Greek yogurt. The fact that the containers are so full tells me they haven't lost much water. I dropped about a tablespoon of darvan 7 into one of the containers, mixed it up, but it didn't thin out much. I feel like that much darvan should have deflocculated the glaze. Any thoughts?
  12. Would this give me a pit fired look with a food safe interior? Create vessel from cone 6 raku clay. Put food safe cone 05 liner glaze inside. Bisque fire the pot to 05. Pit fire the pot.
  13. Does anybody have an efficient, easy, and fair way of allocating glaze expenses to potters in a community situation? Members aren't charged specifically for firing pots - we just fire up the kilns whenever there's enough ware for a full load. There's a flat monthly fee. If we brushed glazes, we could just have everybody buy their own stuff. But we mix dipping glaze from raw materials and put them in 5 gallon buckets. Casey
  14. I went ahead and used a 5X5 clear gloss on the inside of some mugs. It's probably going to look weird where the glaze surface meets the unglazed surface at the center of the lip. Btw, I'm using Laguna 612 #75 stoneware.

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