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(28 February, 2001)
Several years ago I had a chance occurrence in which I painted Red Iron Oxide ("rio") onto a clear or celadon glaze, and got some drips that appeared to be transparent, but were totally filled with small black spangles. Since then, I've been looking for a stable glaze that will reproduce this effect but isn't too terribly runny.
As of this morning, it begins to look like I may have one.
While working on the Red Tenmoku glaze, I concluded that I had swapped amounts on silica and iron, and had ended up in the wrong compositional region. It being easy enough to swap back, I tried two tests at cone 9 in the electric kiln. These are, respectively, 50 brick clay, 30 wood ash, 4 silica, 16 red iron oxide; and 44 clay, 32 ash, 4.5 silica, 19.5 rio. As you can just barely see (it's hard to get a decent photo of the spangles, which are easiest to see when the piece is in motion in full sunlight), while they certainly didn't make red tenmoku in oxidation at cone 9, I'm not complaining.
Test tiles being notoriously unreliable, my next step is to make up a quantity of this glaze and start dipping actual pieces into it. I'm also running identical test tiles through the kiln at Glen Echo Park to see how they do at cone 11 in reduction. My early suspicion is that they will look very similar, but that's just a dumb guess.
(21 March, 2001)
Here's how dumb it was:
Sorry about the focus. I haven't had a chance to get my camera repaired yet. Note that cone 11 is hotter than cone 9, and that iron is more of a flux in reduction than in oxidation.
I revised the glaze very slightly to spray it on an urn,
and it worked nicely. The sparkly bits are only visible
in sunlight, so I haven't got a good photo of it.
(21 March, 2001)
Speaking of sparkly bits: my first attempt at making gold spangles failed, but it may give me an interesting glaze once I get it to stop running like water:
800x600 version
1280x960 version
Sorry parts of that are out of focus. The best crystals
are at the left edge, just at the top of the drip. I am
very pleased with the color of the crystals, and the
brown areas in between are a good foil for them.
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Last modified: Tue Mar 1 02:51:18 EST 2005
