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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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OP
Carpal Tunnel
Joined: Jan 2001
Posts: 13,858 |
One of the spelling words. I had a lot of trouble finding out much about it. It descibes a type of ceramic apparently made almost excusively by the Etruscans. It is uniformly all black, and the color was produced by second firing under reducing conditions, so that the black color is that of carbon, not of a metal in the glaze. For a sample see URL: http://www.dia.org/collections/ancient/theetruscans/F70.46.htmlI found many interesting words about ceramics in the search, but suppose nobody else is likely to be interested in those words. The URL shows a "kantharos" a four inch high drinking cup, with very large handles almost like rabbit ears. The Etruscans must have been "two fisted" drinkers. The handles seem way out of proportion to me.
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Joined: Sep 2001
Posts: 6,296
Carpal Tunnel
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Carpal Tunnel
Joined: Sep 2001
Posts: 6,296 |
What did the Greeks use to get that black over terracotta?
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Joined: Jan 2001
Posts: 13,858
Carpal Tunnel
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OP
Carpal Tunnel
Joined: Jan 2001
Posts: 13,858 |
Dear WW: When a flame coes not have enough oxygen mixed with the fuel to burn it all,
it has a lower temperature, is less bright, and may smoke. Surely you have seen a candle
whose wick has gotten too long and is too straight, so tip is not burning brightly in outside
portion of flame. There is not enough oxygen mixed with the vaporized wax, and it smokes
because the wax is not completely burning. If you hold test tube over the flame, the bottom
gets coated with soot. The bucchero pottery was evidently in second firing had air supply
reduced, producing soot which blackened the pottery. I can't help wondering what the glaze
was that could vitrify under those conditions. Lead could do it, perhaps. And maybe (as a
jest,) that was what caused the downfall of the Etruscans.
Incidentally, going back to the candles, there is a trick to the wick, One of the fibers has to
have more tension than the others, so that when the wax melts, it can contract slightly,
and meake wick end curl and poke out through side of flame where it reaches enough
oxygen to burn with a much brighter yellow than any other part of the flame. When I made
candles, I could not reproduce that effect, and my candles were obnoxiously smoky.
That's my theory about wicks. Maybe other members know more about the secret pf
making the wick curve out of the flame.
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