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Post by adammacmillan on Apr 25, 2018 15:57:08 GMT -6
Hi folks,
I recently moved to a new area and studio that has a Geil autodamper. I plan on doing some high fire crystalline glazing, but I haven't used the kiln yet. Can anyone recommend an oxyprobe setting or cycle that will prevent the zinc from boiling out at peak temp (Cone 11)? I really have no idea of the limitations and function of the kiln yet.
All the high fire reduction crystals I have done involved electric going up, and reduction below 1100C.
Thanks!
Adam
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Post by billcampbell on Apr 26, 2018 8:13:33 GMT -6
Adam,
The issue with a gas kiln is not how hot that it gets, but the atmosphere during the heat up. Zinc oxide is a good flux, but can bite you if you reduce it before it it is incorperated into the glaze.
Zinc oxide will turn into the metal zinc if reduced before it is melted into the glaze. Zinc as a metal will boil at a fairly low temperature. That will cause blisters.
Just be careful to keep your kiln in oxidation, or neutral until the glaze has melted. Once it is in the melt you are safe.
I routinely fire my gas kiln to cone 11, and 12 without blisters.
Bill Campbell
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Post by salman on May 5, 2018 4:50:11 GMT -6
Hi Bill,
Could you elaborate a bit more, the temperate range in which zinc metal boils?
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Post by wmcampbell on May 5, 2018 8:28:57 GMT -6
Adam
The issue is not the temperature that zinc boils at. The issue is not to convert the zinc oxide into the Metal Zinc.
Once the zinc oxide becomes part of the melt the glaze is safe to reduce. You will need to work with your glaze to figure out when it has melted. I would hope that you wouldn't reduce until you have reached your maximum temp, or waited until the glaze has begun to cool.
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Post by adammacmillan on May 17, 2018 11:40:34 GMT -6
Bill, so if i'm following you correctly, I could technically fire non-crystalline reduction glazes and crystalline glazes in the same fire, as long as i'm reducing above the glaze melt temp. Which I am calculating to be around Cone 1. Only problem will be with the glazes that like reduction lower than that.
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Post by Arnie Benton on May 19, 2018 14:13:03 GMT -6
I did a number of crystalline glaze firings with a Geil -
I agree with Bill -
It's much better to reduce during the crystal forming ramps as the kiln cools - and for me the most pleasing results came from reducing after all the crystals were formed - at 1750 to 1700 F.
Arnie
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joerg
New Member
website: www.crystalsforever.com
Posts: 49
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Post by joerg on May 19, 2018 15:16:51 GMT -6
I did a number of crystalline glaze firings with a Geil - I agree with Bill - It's much better to reduce during the crystal forming ramps as the kiln cools - and for me the most pleasing results came from reducing after all the crystals were formed - at 1750 to 1700 F. Arnie I fully agree with Arnie....I reduce at the end of the crystals forming phase, i.e. after 3-4 h, reducing (down) from 2000 F to 1750 F at rather low pressure...in 1 h... |
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Post by mariscal on May 29, 2018 4:09:36 GMT -6
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Post by mariscal on May 29, 2018 5:13:31 GMT -6
youtu.be/0WxWIe8_6mARedution firing reduction 1085º 30 minutes reduction 1045º 1 hour too complete firing video
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