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Norm Stuart

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  1. It could be that too much lead has evaporated from these ^6 glazes if you fire too slowly. I found a ceramics journal from 1904 which quantifies the percentage of the lead in a glaze, fired in a sagger, which vaporized per hour. Journal of the Society of Chemical Industry, Volume 23 - Society of Chemical Industry (Great Britain) 1904 http://books.google.com/books?id=lkLOAAAAMAAJ&pg=PA470&dq=kiln+firing+%22lead+glaze%22+loss+per+hour&hl=en&sa=X&ei=qhTnUpKpAYPvoASxlIGoCw&ved=0CDsQ6AEwAA#v=onepage&q=kiln%20firing%20%22lead%20glaze%22%20loss%20per%20hour&f=false Without rereading it I think the volatilization of lead per hour at cone 6 was about 1/3 per hour. At higher cones it's quickly gone. These commercial glazes are partially lead fluxed manganese glazes which form a green, blue or red glass, with a reflective layer of gold or silver on the surface. The key to success with these glazes seems to be having a very smooth bisque surface and a thick application that often runs. The Amaco Palladium has a tendency to pinhole on many clays which I've only seen in fluorine containing frits like Ferro 5301 and 3269. I prefer the reliability of the ^05 gold glaze, which becomes especially gold when placed over a previously fired ^6 glaze to provide a smooth surface and protection against clay off-gassing.
  2. Metallic Rain, which I have not tried, is similar in chemistry to Spectrum Metallic Mirror and Amaco Palladium. Amaco says their leaded Palladium is not dinnerware safe, but Spectrum says leaded Metallic Mirror is food-safe based on the glassy non-leeching finish of the glaze "Contains some heavy metals and/or cadmium compounds but passes test for lead and cadmium release.". You need a small amount of lead to create this type of look. But they don't use enough lead to make these glazes reliable. I think you'd be far happier with a standard ^05 lead-manganese glaze like these sold by Clay Planet - very reliable, but not food safe. http://shop.clay-planet.com/pint-722-aztec-gold.aspx
  3. The pine cone is a collection of bisqued leaves assembled into a core of non-shrinking ceramic paste, then rebisqued and glazed. Manganese glaze covers the core and inner part of the leaves.
  4. Return of the Duck in Orange Sauce. An assemblage of a variety of ^6 glazed clays and porcelain pieces assembled with low-fire glaze and low-fire glaze mixed with orange COE 96 glass frit. The New Zealand Frost Orange wedge is filled with orange COE 96 glass frit, with an orange mason stain on the rind covered by a thin layer of low-fire clear.
  5. I tried to capture the look of photos of various ducks landing on water. This particular duck had to land in a pool with a wingspan no wider than our kiln, so he had to be captured at the moment he began tucking his wings back into a retracted position. I made it with Laguna WC-370 Amador clay which has so much grog it's almost like using paper-clay. The companion piece, Return of the Duck in Orange Sauce, is an assemblage of a variety of ^6 glazed clays and porcelain pieces assembled with low-fire glaze and low-fire glaze mixed with orange COE 96 glass frit.
  6. You can do much the same thing with Copper Carbonate or oxide with Ferro Frit 3269.
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