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Reduced
Apr 16, 2019 1:07:38 GMT -6
Post by salman on Apr 16, 2019 1:07:38 GMT -6
Thanks mohawkpiper
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morgan
New Member
Darn...lot of good info on the old forum. Sad that it got unstable. But whadya do?
Posts: 21
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Reduced
Jun 10, 2019 5:53:01 GMT -6
Post by morgan on Jun 10, 2019 5:53:01 GMT -6
I have only done a couple of reduction firings and Salmon's closeup of the top of the red/green vase with the very small hole has what appears to be some bubbling of the glaze. On my second reduction firing I had several pots that had perfect glaze finishes to begin with, but in the reduction firing the glaze bubbled badly...to the point of being unsaleable. Might I have gotten too hot, or ramped up too quickly? The pots with bubbles were at different locations in the kiln. I was at the top hold (1450F), about 15 minutes into a planned 30 minute hold when a wind gust blew out my pilot. Of course, the gas shut off and the temp shot up to a little over 1600F before beginning to cool. Might this have caused the bubbles? Most of the glazes that bubbled were copper carb dominate.
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Jun 21, 2019 1:16:52 GMT -6
Post by mariewright on Jun 21, 2019 1:16:52 GMT -6
Hey Morgan,
In reduction, Zinc oxide turns to Zinc metal and vaporizes away. I suspect this is what's going on. I am not a reducer, but from what I have picked up over the years, you can reduce after the crystals have been formed, during the cool down. I would try reducing around 1500F, and even a light reduction can be enough.
Cheers, Marie
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Jul 12, 2019 14:09:45 GMT -6
Post by mohawkpiper on Jul 12, 2019 14:09:45 GMT -6
again, its been years since ive done anything hands on, but back in the day i was doing more reduction than oxidation. early on i had some bubbling here and there, never seemed consistent with anything. sometimes copper carb, sometimes titanium. i think once even cobalt. never happened often tho. id attain it to “too close to the elements” or “too hot” or “cooled too fast”. but i started doing high temp reductions (2000*F-2100*F) and id load up the kiln sometimes with things close to elements and regularly stuff would come out great, glassy and smooth so i ruled out too hot and too close to the elements. i slowed down my firings overall just over time so maybe it was ramping up or down quickly in temp. or maybe it was just some exact precise environment that was hard to replicate. not sure.
but id say give it a go again and again. dont let it stop you.
G
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Jul 12, 2019 14:20:03 GMT -6
Post by mohawkpiper on Jul 12, 2019 14:20:03 GMT -6
I think i overlooked that these were refires you were talking about... different stuff happens then i guess. id watch the speed up and the hold at the top on the second firing. i forget at what point the glaze remelts, (maybe its a lot higher), but it does remelt at some point, and it starts to do so in a manner where it looks like dry river bed cracks where it pulls away from each other before it remelts and smooths back out. if you are hitting that point, it could be the cause of the bubbling. maybe a longer hold at the top to help with the remelt, or a lower top temp second firing so you dont hit that point, or make sure to go through it to a higher top temp to make sure you have allowed for sufficient remelt?
if you can, take a look inside from time to time on the way up in the second firing and note what the glaze looks like at intervals.
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Jul 12, 2019 22:22:59 GMT -6
Post by mikemangion on Jul 12, 2019 22:22:59 GMT -6
Hi Morgan,
I believe José will be able to add to the insight that G has been able to provide mate. Have a good one guys, Mike.
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