Bill Merrill on thu 13 sep 07
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I keep reading about the Shino glazes. Shino glazes are rebels. They
are illusive, allusive until you make you peace with the fact that they
are. One of the first carbon trap glazes was a glaze called "Wirt
carbon trap, which is a American shino type glaze. The glaze usually
has spodumene in it. Spodume is very different from mining location to
mining location. It can be iron free, white to orange and react quite
differently from on another. My favorite spodumene when fired, the
fusion button is pale=20
Orange and grows to twice the size of the original fusion button size.
When used in flame ware bodies, potters would open their kilns and find
the lids of their pots stuck to the shelf above the pot due to the
growth of the clay body. Foote Mineral was the company that had in my
opinion the best spodumene. It is no longer produced. The Australian
spodumene is iron free, so may be a little iron would make it have the
color of the Foote Spodumene. If the spodumene that potters are now
using don't swell
Up 2-3 when fired by itself, I wonder how the glaze calculator people
are going to operate? I still use the old stuff.
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Here is a Carbon trap glaze to try (Wirt carbon trap)
F-4 1800
Spodumene 1500
EPK 250
Soda ash 400
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This is a revised Carbon trap (revised Wirt)
Neph Sy 2500
OM-4 833
F-4 2540
Spodumene 2125
Epk 395
Soda Ash 567
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I am looking in my notes from 30 years ago to find the original Wirt
glaze. It is more simple than the ones above and was very versatile, I
will try to find it and will post the glaze when I locate it.
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The best results I had were on bodies that weren't high in iron. The
reduction started at 1650 degrees and I over reduced, as I smoked the
one side of the kiln so I got
excessive reduction by closing down the primary air. After an hour I
went back to less reduction for the remainder of the firing. I got
lustrous silvery surfaces on the glaze to black and grey as well as
orange where the glaze is thinner. These type glazes are exciting to
use. Just remain an explorer and keep an open mind. Don't give up too
soon, the best pots are those you haven't made yet!!
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Is anyone going to the Shaner opening (retrospective) in Tempe on the
28th? If so I'll see you there!
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Bill=20
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billm@pcadmin.ctc.edu
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