Cone 10 reduction: why not cone 6?

As a young potter I was seduced by the immediate intimacy of cone 10 reduction glazes. They just gave-off a certain depth to what is after all a very thin surface. But this is not the only seduction of cone 10 reduction glazes: they do the heavy lifting of purposeful design work and leave the artisan potter to the business of form. Form and efficiency become everything safe in the knowledge that the design work is an auto-performance by the delicate dance between the right glaze and the right luck in the environmental parameters of your specific cone 10 reduction kiln. Most Kilns are so poorly insulated and what is worse so poorly sealed that it is very much a game of chance each time the kiln is fired. Sure after 5 years with the same kiln, after of course settling into the same glazes, there is a certain predictability to the the outcome–but god or chance is always in the works. Hence, depending on the size of your kiln, 2 two 6 times a year Christmas arrives early.

After a 10 year absence from the craft, I took up the trade again. My only access was to cone 6 oxidation. It turned out to be a really good challenge. As everyone who has produced and trained on cone ten reduction knows cone six oxidation is an object of scorn if not ridicule. Those potters, it is often heard, produce nothing but bread a butter ware: we cone ten reduction are the true risk takers.

My experience with cone 6 oxidation suggests the inverse. Many C10R potters rely on the seductive qualities of C10R glazes and at best fail to develop a conscious sense of deliberative design while relying on strong form, and at worst pass-off bad forms with complex gazes. In short, if you want complexity in an environment of cone six oxidation you have to try for it: the glazes will not deliver up accidentally or consciously complexity in surface treatment. Each layer of complexity has to be successively built up.

But after this observation I had the inclination to ask why cone 6reduction had not become popular. After all the difference in temperature between cone six and cone ten is not inconsequential to the economics of a pottery. Both the cost and duration of kiln construction can be reduced if the target temperature is reduced by a not inconsequential factor. Furthermore commercial cone six clay bodies mature (degree of verification) is comparable if not superior to cone 10 clay bodies. So why not cone six reduction? Potters could economize on the fix costs of kiln construction and on the cost of fuel. Perhaps there remains the belief that cone six glazing materials are more costly than cone 10 glazes thus the perceived cost savings is dulled.

I am not sure about that. Any non-fritted cone 6 glaze runs the same cost as a cone 10 glaze. The only exception being cone 11 translucent porcelains. But even here I am skeptical. Is it true that engineered cone 6 porcelains are less engineered than cone 10 or 11 porcelains? My personal opinion is that high fire cone 10-11 is anachronistic, a gross waste of materials and fuels but it may be that I am wrong.

Update: for a visual verification that cone 6 reduction can be just as interesting as cone 10 see this article in CM.

3 thoughts on “Cone 10 reduction: why not cone 6?

  1. i agree! i have a kiln in the works that i am dedicating to cone 6 reduction. tradition and familiarity are the only reason c10r is so commonly practiced.

    • I have rethought things a bit. But just a bit. Outside of true porcelain is there any reason to do cone 10 reduction? But, and here is the but, at cone six you really need to work with good clays, i.e., those that truly mature at cone six. I have worked with many cone six “school” clays that are simply under vitrified at cone six.

  2. I wanted to share some of our cone 5/6 adventures. There are definitely issues with the non-porcelain bodies not being vitrified, but b/c we use mostly porcelain we have been having fun playing with the 5/6 in reduction. Also, your clay body will be more vitrified in a reduction environment. We have even gotten the allusive carbon trapping as well at 5/6. More schools are going to 5/6 b/c of energy cost, but it’ll be a little slow until people are willing to look at the amazing 5/6 results.

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