Lily Krakowski on wed 3 sep 03
As Paul Lewing says, electric firing is its own thing, and produces its own
beauties. It is harder to get glorious results with it because the fire
itself does not help--but we have done that all before.Just look at Emmanuel
Cooper's books--their illustrations.
HOWEVER. NO MANGANESE. I have checked this out and although granular
manganese is granular it can be ground down, it is NOT a material you want
in the dust, it certainly is NOT a material you want to rub your hands
against as you work. Or why fewer and fewer clay bodies with MnO2 in'em
are on the market (If any.)
If you want speckles, try rust. Be very careful to eliminate sharp bits,
and wear eye protection if you pound or grind it. And remember to keep the
clay isolated from the rest because one them there specklers are in, they
are IN for good.
Lili Krakowski
Constableville, N.Y.
Be of good courage....
Rick Monteverde on wed 3 sep 03
Lily -
>If you want speckles, try rust. Be very careful to eliminate sharp bits,
>and wear eye protection if you pound or grind it. And remember to keep the
>clay isolated from the rest because one them there specklers are in, they
>are IN for good.
I think you're saying to work the rust into the moist clay here, right?=
Could it be applied to the surface of greenware or bisque too, or in those=
cases would it get burned away or washed out into the glaze without having=
much visual effect? I'm going to try this. My truck would be a good source=
of raw material for starters.
- RM
Christena Schafale on wed 3 sep 03
Lili,
I'm with you about avoiding exposure to hazardous materials when possible,
and in fact, I recently switched to a clay that does not contain
manganese. However, believe me, there are MANY mid-range clay bodies out
there with manganese included for speckling. Maybe Ron can comment on
this one -- is there really a trend toward eliminating this practice?
Chris Schafale
> Or why fewer and fewer clay bodies with MnO2 in'em
>are on the market (If any.)
Light One Candle Pottery
209 N Woodrow St
Fuquay-Varina, NC 27526
(919) 567-1098
candle@intrex.net
www.lightonecandle.com
Clayart Spring Gallery: www.lightonecandle.com/clayartgallery.html
Snail Scott on wed 3 sep 03
At 08:15 AM 9/3/03 -0400, you wrote:
>HOWEVER. NO MANGANESE....it is NOT a material you want
>in the dust, it certainly is NOT a material you want to rub your hands
>against as you work.
I was under the impression that the skin-absorption
hazard from manganese was negligible, and that the
inhalation hazard is not much higher. It's the fumes
from firing that make manganese a serious danger.
-Snail
Vince Pitelka on wed 3 sep 03
> HOWEVER. NO MANGANESE. I have checked this out and although granular
> manganese is granular it can be ground down, it is NOT a material you want
> in the dust, it certainly is NOT a material you want to rub your hands
> against as you work. Or why fewer and fewer clay bodies with MnO2 in'em
> are on the market (If any.)
Now now, dear Lili, don't be an alarmist. There is no danger of skin
absorption with manganese unless you have open wounds, and god forbid anyone
with open wounds should be handling ANY glaze materials. Of course you want
to avoid breathing the dust, but the kiln fumes are the real danger.
Manganese can easily be used very safely in the studio.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Office - wpitelka@tntech.edu
615/597-6801 x111, FAX 615/597-6803
http://iweb.tntech.edu/wpitelka/
John Hesselberth on thu 4 sep 03
On Thursday, September 4, 2003, at 08:40 PM, Mildred Herot wrote:
> My question deals only with manganese dioxide. For many years I used
> a base
> glaze on green ware which consisted of 80 Albany Slip (now Alberta
> Slip) and
> 20 manganese dioxide. I enjoyed using this since what I would put a
> was
> resist design on the bisqued pot and the glaze I used broke over the
> base
> and my design was still there and clear... I would
> like to know if this formula is safe and that I can continue to use it
> if I
> so desire.
Hi Mildred,
Like so many things we deal with in pottery, the answer is "it
depends". If you are using this on sculptural work and are taking
proper safety precautions in handling the manganese powder and avoiding
the fumes during firing--sure it can be used safely. But you must know
what you are doing, safety-wise.
However this glaze would probably not be suitable for functional work.
While Albany slip makes a pretty well balanced glaze by itself, 20%
manganese dioxide is way more than a glaze can hold. It will probably
leach a lot of manganese in use. You can have it professionally leach
tested at modest cost if you want to know how much. As a quick and
dirty check, try soaking part of one of your pieces (or part of a test
tile) in vinegar for 3 days and see what happens. If, after rinsing and
drying the piece, you can see any fading you really don't have a
satisfactory functional glaze.
Regards,
John
http://www.frogpondpottery.com
http://www.masteringglazes.com
Mildred Herot on thu 4 sep 03
My question deals only with manganese dioxide. For many years I used a base
glaze on green ware which consisted of 80 Albany Slip (now Alberta Slip) and
20 manganese dioxide. I enjoyed using this since what I would put a was
resist design on the bisqued pot and the glaze I used broke over the base
and my design was still there and clear. I have not been as sucessful with
Alberta as with Albany and, consquently, have not done this too much lately.
However, I really didn't know there was a problem with Manganese until now
(and I am truly sorry I didn't discover Clayart a long time ago). I would
like to know if this formula is safe and that I can continue to use it if I
so desire. Thanks for your help, Mildred Herot
----- Original Message -----
From: "Vince Pitelka"
To:
Sent: Wednesday, September 03, 2003 9:08 PM
Subject: Re: Oxidation like Reduction????
> > HOWEVER. NO MANGANESE. I have checked this out and although granular
> > manganese is granular it can be ground down, it is NOT a material you
want
> > in the dust, it certainly is NOT a material you want to rub your hands
> > against as you work. Or why fewer and fewer clay bodies with MnO2
in'em
> > are on the market (If any.)
>
> Now now, dear Lili, don't be an alarmist. There is no danger of skin
> absorption with manganese unless you have open wounds, and god forbid
anyone
> with open wounds should be handling ANY glaze materials. Of course you
want
> to avoid breathing the dust, but the kiln fumes are the real danger.
>
> Manganese can easily be used very safely in the studio.
> Best wishes -
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Technological University
> 1560 Craft Center Drive, Smithville TN 37166
> Home - vpitelka@dtccom.net
> 615/597-5376
> Office - wpitelka@tntech.edu
> 615/597-6801 x111, FAX 615/597-6803
> http://iweb.tntech.edu/wpitelka/
>
>
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Ron Roy on thu 4 sep 03
I wonder what "alarmist" means and I wonder what the opposite of alarmist is?
There are some situations when the dust can be the bigger problem -
especially when the dust is constantly stirred up by moving air.
No sense in minimizing the dangers when dealing with toxins - there are
always those who will continue to ignore the problems no matter what is
said - on the other hand no one should suffer because they did not know
what the dangers were.
RR
>Now now, dear Lili, don't be an alarmist. There is no danger of skin
>absorption with manganese unless you have open wounds, and god forbid anyone
>with open wounds should be handling ANY glaze materials. Of course you want
>to avoid breathing the dust, but the kiln fumes are the real danger.
>
>Manganese can easily be used very safely in the studio.
>Best wishes -
>- Vince
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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