Earl Brunner on tue 3 oct 00
I know that very fine silicon carbide has been used to make
copper reds in oxidation firings, I was wondering if this
(artificially induced or localized reduction might be used
in other glazes (like tenmoku) to get similar reduction
results? Has anyone considered or done this?
the Pottery Place wrote:
>
> I very much want a Tenmoku glaze, so much so that i bought a commercially prepared one. (cone 10). My questions would be, must it be reduced? and, when i made up a pound of it for testing, it is extremely thick when adding the prescribed amount of water.. Is this glaze thick and applied that way, or can i thin it to a "normal" consistency? I fire natural gas. gary@thepotteryplace.com
>
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Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Paul Lewing on wed 4 oct 00
Earl Brunner wrote:
>
> I know that very fine silicon carbide has been used to make
> copper reds in oxidation firings, I was wondering if this
> (artificially induced or localized reduction might be used
> in other glazes (like tenmoku) to get similar reduction
> results? Has anyone considered or done this?
Hi, Earl,
I have tried this several times, and the silicon carbide I use is 1000
mesh from a lapidary company. Most that you buy from a ceramics
supplier is not fine enough, but this stuff is incredibly fine powder.
Anyway, it never seemed to have any effect on color at all. Sometimes
it made the glaze bubble, though. And I asked the Glaze Doctors at
NCECA (can't remember who they were those years) two different years.
They had never heard of anyone having any success at reducing iron this
way, and I've never heard of anyone making it work either. Sure would
be neat if it would work, though, wouldn't it?
Paul Lewing, Seattle
vince pitelka on wed 4 oct 00
As I understand it, red ferric iron breaks down to black ferrous iron at
high-fire temperatures, regardless of kiln atmosphere. Where the glaze is
thick, that black color should be preserved, while where thin, it will
re-oxidize to red-iron at lower temperatures. So you should get a good
temmoku with colors breaking from black to red-brown whether you fire in gas
or electric. No reason for any local reduction agents.
Best wishes -
- Vince
Vince Pitelka
Home - vpitelka@dekalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
http://www.craftcenter.tntech.edu/
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