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Rick Wise

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Everything posted by Rick Wise

  1. I'm going to try my first OBVARA firing this week-end. I've read that the pieces need to be bisqued to 1825F first, and then fired to around 1650F for the "dunk into the goop". My question is: Can this all be in one firing? That is to say -- can I fire them to 1825, then allow them to cool down to 1650 -- and dunk them? Or do they need to cool all the way back down from their bisque firing and then be heated up again in a second firing? Any advice will be greatly appreciated.
  2. Mosey Thanks for this thoughtful description. I will try it. You say: "I would mix well with a stick before using." How would you describe the consistency after this mix? Pudding? Room temp butter? Syrup? Sour cream? ( I think I must be hungry)
  3. Many thanks to you all. Potters are very generous with their time and expertise!
  4. I have encountered a glaze recipe (below) I want to try that calls for "Frit 4124" but I cant find that available or any info on what it is or what may be a suitable sub. Any ideas? 31 Silica 17.6 Frit 4124 17.6 Whiting 13.4 Kaolin 10.4 Zircopax 10Total base recipe100 Copper Carbonate 2Total102
  5. Doubt it as it is the same body I have been using for some time. Same clay, same glazes, same techniques other than more trimming of the upper walls.
  6. After several years of successful cup making I have recently had a rash of cups that come out of the glaze firing (electric, cone 6) with invisible cracks in them. The cracks run generally top to bottom and are hard to see until you know they are there. But if you thump them the flat sound gives it away. Some are ok at first and crack only upon being filled with hot coffee for the first time. I'm looking for an explanation. My hypothesis is this: I have recently been trying to get more weight out of them at trimming. I start with 16 oz of clay and try to trim down to less than 1
  7. When I first learned about terra sig I just fell in love with the look it produces on greenware. But then realized that the look disappears upon firing (Cone 6 stoneware). Is there a way to keep that satiny, shiny lustrous look but still fire it high enough to have functional ware?
  8. Since asking this question I've been doing some experiments using (1) magic water (2) Spooze or (3) mix of clay, tissue paper, vinegar and water -- attaching handles to overly dry cups. I have to say that (3) appears to be a clear winner.
  9. Just what I needed to know Pres -- thanks.
  10. Pres -- you say you like and use Magic Water. I know the recipe, but not how its used. Am I correct that you use it along with plain slip? Or do you make the slip with the Magic water?
  11. There is a lot of discussion in this thread regarding the best ways of joining clay -- some favor Magic Water, some favor . I find this perplexing since vinegar () is a flocculent, and sodium silicate (Magic Water) is a deflocculant. Right? How is it that both may work? In other words, what is the contribution of each (floc or defloc) to this process? It would seem logical that one or the other must be counterproductive. (I have heard the wonderful Phil Berneburg of Washington Street Studios question the utility of vinegar in this application) Full disclosure: I have been
  12. Cracks are all the way thru cup not just in glaze. They leak.
  13. I will try to post pic tomorrow. As to "poor glaze fit" I assume that means a poor matching of glaze with that particular clay? It was a clay/glaze combo that is my standard with a long history of success. But re the "unvitrified body" -- might that be from a firing that got interrupted by a power outage?
  14. Puzzling new experience for me. Two cups -- both from the same firing -- I sold to a lady cracked upon first use -- when she poured hot liquid in them. Cracks were jaggedly vertical -- almost invisible but allowing leaks from the cups. They had appeared to be fine when they came out of the kiln -- perhaps thinner than most but I was pleased -- not worried -- about that fact. Anyone care to venture some ideas why this would happen? I'm now worried about others that may have failed -- or will fail --without my knowledge.
  15. I have always fired my electric kiln to cone 6 with 4 peepholes closed and the 5th (top one) open all thru the firing. I have now installed an Envirovent II (downdraft venting system). Should I now fire with all holes closed?
  16. I think I understood Hsinchuen Lin to say that he was able to fire a lidded jar by painting aluminum hydate along the area where the lid meets the jar -- in other words, to keep the glaze from sticking the lid to the jar when fired. I often fire the 2 pieces of a lidded jar in place but only after very carefully removing all traces of glaze from the area where they meet, and sometimes they still stick. Is applying aluminum hydrate a "thing"? If so, do I just mix it with a little water and paint it on?
  17. Lately, my handles have been cracking like shown here -- probably 20 to 30% of them. It occurs in the same spot at the bend of the curve and after they have been turned and are going to bone dry. (If they make bone dry OK they never crack later.) Not sure why since the clay and the techniques are all my usual. At any rate, it seems to me that there should be something I could do to help prevent this but I cant figure out exactly what it happening. All ideas welcomed.
  18. A question: I want to run a test of what a particular clay/glaze combo looks like at various cone levels -- for instance, cones 5, 6 and 7. Can I fire a single piece at Cone 5, let it cool, examine it, then place it back in the kiln, fire it to Cone 6, let it cool, examine it, then fire it to Cone 7? If I do that will I see results just as if I had fired each of 3 different pieces to just one of the cone levels I want to test? Or do the repeated firings have a cumulative effect?
  19. Pres -- could you post a pic of those "plumbing parts"? I LOVE my Giffen Grip! Only problem is trimming the foot on -- for instance -- a tall narrow necked bottle. The head of the piece (pointing downward and touching the wheel) moves off center. I try to resolve this problem by using clay lugs around the head to secure it or by letting the head rest on (and pushed slightly into) a thin layer of clay. But all these methods leave a bit to be desired. Seems to me that what is needed is a GG accessory that mounts in the center, is shaped like a cone, and extends upward to a point so that th
  20. Would someone care to explain why slip recipes always say to begin with bone dry clay? Is that somehow better (or the end result different) than using wet clay. Its as if the instructions for boiling water said "First take some ice cubes ....."
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