John Hesselberth on mon 19 feb 01
Annette Vickers wrote:
>Hello, I am trying to find someone that understands the use of copper oxide
>in glazes. Does anyone have any idea where I can find how much copper oxide
>is used in the U.S. and internationally for this application? Also can
>anyone comment on its use and some of the other alternatives to using
>cuprous (copper) oxide as a pigment for ceramics.
Hi Annette,
Copper oxide (or the carbonate which is most often what potters buy and
use) is used frequently by studio potters, but not so much by the
manufactured pottery industry. Studio potters like it because it gives
some uniqueand attractive shades of green (and red in reduction) that
just aren't obtainable with chromium oxide--the other primary source of
green. It is one of the most difficult materials to retain in a glaze
and the glaze has to be very well formulated to not leach copper on
exposure to acids. It is specifically not recommended in lead-containing
glazes because it increases the leaching of lead. The published
literature is full of references to this.
Lead free glazes can be formulated which will hold up to 5% copper
carbonate with a low level of leaching. I haven't a clue what the total
useage in ceramic glazes might be--not much since the big outfits don't
use it very much. As an indication of this, you won't find a single
Mason stain that contains copper. Mason gets its greens from chromium
oxide blended with other colorants to cut the garish green that chromium
by itself can give.
Regards, John
"The life so short, the craft so long to learn." Hippocrates, 5th cent.
B.C.
Annette Vickers on mon 19 feb 01
Hello, I am trying to find someone that understands the use of copper oxide
in glazes. Does anyone have any idea where I can find how much copper oxide
is used in the U.S. and internationally for this application? Also can
anyone comment on its use and some of the other alternatives to using
cuprous (copper) oxide as a pigment for ceramics.
Snail Scott on tue 20 feb 01
At 09:29 PM 2/19/01 -0500, you wrote:
>Annette Vickers wrote:
>
>>Hello, I am trying to find someone that understands the use of copper oxide
>>in glazes. Does anyone have any idea where I can find how much copper oxide
>>is used in the U.S. and internationally for this application?
Years ago, a friend of mine did a conceptual
installation artwork about clay, showing how
little is used for tableware and art-ware
even with the commercial producers figured
in. (The amount used by studio potters was
infinitesimal.)
He got his data from a huge (U.S.) government
publication on mining production. I don't
recall the name, but ask a reference librarian-
they are gods!
-Snail
Maggie Woodhead on tue 20 feb 01
Hello Annette and Kia ora
I use Cuprous Oxide in my glaze when firing for copper reds in reduction.
My own idea but other than the chemical changes in reduction do not have a
terribly intellectual reason. It does seem to work though. Have had some
really good reds in only four firings. Still learning!!!
----Best Wishes Maggie----
maggiew@clear.net.nz
----- Original Message -----
From: "Annette Vickers"
To:
Sent: Tuesday, 20 February 2001 11:03
Subject: cuprous oxide
Hello, I am trying to find someone that understands the use of copper oxide
in glazes. Does anyone have any idea where I can find how much copper oxide
is used in the U.S. and internationally for this application? Also can
anyone comment on its use and some of the other alternatives to using
cuprous (copper) oxide as a pigment for ceramics.
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