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About mrcasey

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    Advanced Member

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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. I've spent the entirety of my time as a potter using various cone 6 stoneware. In our studio, we have access to a white body (Laguna #65). What is the advantage, if any, to switching to a cone 6 porcelain?
  2. The only reason to cover the pot is to keep unsafe volatile material out of the liner glaze.
  3. Suppose that I throw a raku clay pot, put a liner glaze in it, and fire to cone 6 electric. Suppose that I then put a clay cover over the pot rim and pit fire it. Would that give me a food safe vessel? What if I just used regular food safe cone 6 clay?
  4. 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?
  5. 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
  6. mrcasey

    Deflocculate Or Add Water?

    Isn't this backwards? If the glaze hard layers on the bottom, it needs flocculated.
  7. mrcasey

    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...
  8. mrcasey

    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!
  9. When a glaze is really thick, how does one know whether it needs more water or needs to be deflocculated?
  10. What is the error range on such a scale? 1/2 gram maybe?
  11. I broke the hydrometer so I'm using a 100 mL graduated cylinder and a Harbor Freight electric gram scale accurate to .1 gram.
  12. 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?
  13. 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.
  14. 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?

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