Don Goodrich on thu 23 nov 06
Wes,
The traditional way to achieve nonglazed flat blacks is to smother
the wares after firing. Use horse manure, or a mixture of manure and
sawdust. Make sure there aren't any little holes to let air in and
oxidize the carbon.
Or you cauld take the easier route and fire them, let them cool,
then use Rustoleum High Heat Bar-B-Q Black paint. Comes in a 12-oz
spray can and will stick better than the pigments you've tried.
Good luck,
Don Goodrich with tongue only partly in cheek
On Thu, 23 Nov 2006 12:59:18 -0500, Wes Bernardini
wrote:
>I'm having trouble producing vessels with matte black paint on a white,
>cone 5, unslipped clay body. I don't want to use a glaze, and I'd prefer
>to fire in an open, wood fire (max temp about 1200F). I've tried
>manganese oxide and black underglaze, but both are "fugitive" after
>firing - that is, I can rub them off with my finger.
>Any suggestions for a black pigment that will stick under these firing
>conditions? I'm willing to fire in a formal kiln to get the pigment to
>stick, but the paint must be matte, not a shiny glaze.
>Thanks for any advice!
>Wes
Wes Bernardini on thu 23 nov 06
I'm having trouble producing vessels with matte black paint on a white,
cone 5, unslipped clay body. I don't want to use a glaze, and I'd prefer
to fire in an open, wood fire (max temp about 1200F). I've tried
manganese oxide and black underglaze, but both are "fugitive" after
firing - that is, I can rub them off with my finger.
Any suggestions for a black pigment that will stick under these firing
conditions? I'm willing to fire in a formal kiln to get the pigment to
stick, but the paint must be matte, not a shiny glaze.
Thanks for any advice!
Wes
Lynne and Bruce Girrell on fri 24 nov 06
Oops, I misread part of your message. I thought that you were planning to
fire to cone 5. Your firing temperature of cone 020 almost demands that you
go to the single fire techniques. Clay and wild spinach juice is what they
use if I recall correctly. I didn't check, though. I'll leave that for you.
Bruce Girrell
Lynne and Bruce Girrell on fri 24 nov 06
Wes Bernardini
> I'm having trouble producing vessels with matte black paint on a white,
> cone 5, unslipped clay body. ... I've tried
> manganese oxide and black underglaze, ...
What's wrong with simply formulating a matte black glaze?
The main problem with what you have tried so far is that you don't have any
binder in there. You need a clay to hold things together.
I suggest that you investigate the techniques used by the potters of Mata
Ortiz and the Native Americans of the American Southwest. Acoma Indians are
well known for their black on white ware. The slip that they use is for
burnishing or for color and is not necessary to get the black lines to
stick. They use single fire methods which helps the pigment lines stick to
the pot better.
If you don't want to single fire then you are basically back to formulating
a matte black glaze. Get a basic black glaze recipe - it will probably be
colored with manganese, cobalt, and maybe a little copper - and then start
adding clay to increase the alumina content. It shouldn't take a whole bunch
more clay until the glaze goes matte. I trust that you realize that this
will not be food-safe.
Bruce Girrell
John Guerin on fri 24 nov 06
----- Original Message -----
From: "Wes Bernardini"
To:
Sent: Thursday, November 23, 2006 10:59 AM
Subject: black on white pottery
> I'm having trouble producing vessels with matte black paint on a white,
> cone 5, unslipped clay body. I don't want to use a glaze, and I'd prefer
> to fire in an open, wood fire (max temp about 1200F). I've tried
> manganese oxide and black underglaze, but both are "fugitive" after
> firing - that is, I can rub them off with my finger.
> Any suggestions for a black pigment that will stick under these firing
> conditions? I'm willing to fire in a formal kiln to get the pigment to
> stick, but the paint must be matte, not a shiny glaze.
> Thanks for any advice!
> Wes
Hi Wes,
Mix your maganese dioxide powder with a dark colored clay. I use Laguna's
Cassius Basaltic which is a dark brown clay. You need a lot of manganese to
overcome the brown clay color, but when fire the clay binds the black color
to the vessel.
Good Luck,
John Guerin
Tucson, AZ
jsmola on fri 24 nov 06
Wes--
I use a wax resist (black) from Aftosa--I have to put it on quite thick, but
it will leave a permanent black matte finish on white (or any clay surface).
It will never rub off.
Jaymes
The Pottery Pimp
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Wes Bernardini
Sent: Thursday, November 23, 2006 12:59 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: black on white pottery
I'm having trouble producing vessels with matte black paint on a white, cone
5, unslipped clay body. I don't want to use a glaze, and I'd prefer to fire
in an open, wood fire (max temp about 1200F). I've tried manganese oxide
and black underglaze, but both are "fugitive" after firing - that is, I can
rub them off with my finger.
Any suggestions for a black pigment that will stick under these firing
conditions? I'm willing to fire in a formal kiln to get the pigment to
stick, but the paint must be matte, not a shiny glaze.
Thanks for any advice!
Wes
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Jaymes
The Pottery Pimp
Ivor and Olive Lewis on sat 25 nov 06
Dear Wes Bernardini,=20
At 1200 deg F there is no fluxing activity so your oxides have nothing =
to bind them to the clay.
You might get away with China decorators pigments or "On Glaze Enamels". =
But even with these you would be on the cusp of failure.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
| |
|
