Kristin on mon 3 feb 03
Flipping through _The Potter's Palette_, I decided I'd
like to do a semi-grid of tests based on manganese
dioxide and other oxides and one of RR/JH's base
glazes.
So I spent about 4 hours this weekend measuring out
about 25 glaze batches (yes, I work slowly). Then I
went back and started trying to add water and sieve.
They won't make it through my 80-mesh sieve. In fact,
I would guess these little chunks of manganese dioxide
wouldn't make it through a kitchen strainer.
I searched the archives for a reference to this, and
have only found references and discussions about the
toxicity of this chemical, which makes me think maybe
I shouldn't be messing with it at all.
But I have put the time into doing all of this
measuring, the money in the chemicals, etc., so I'd
like to follow through. Can someone tell me if
there's a way to make these little chunks dissolve in
water? All of the test batches have water added now.
I thought maybe sitting for a while would help.
Didn't, as far as I can tell.
Thanks again, everyone.
(I am not positive, but I think what I have is
"24-40," I guess that refers to the size of the little chunks?)
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Paul Herman on mon 3 feb 03
Kristin,
It sounds like you have GRANULAR manganese dioxide, from 24 mesh to 40
mesh size. It's hard, and won't dissolve. What you need is the powdered
form, manganese dioxide (cheap), or manganese carbonate (expensive).
good luck,
Paul Herman
Great Basin Pottery
423-725 Scott Road
Doyle, California 96109 US
potter@psln.com
----------
>From: Kristin
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Manganese Dioxide: insoluble?
>Date: Mon, Feb 3, 2003, 7:57 AM
>
> (I am not positive, but I think what I have is
> "24-40," I guess that refers to the size of the little chunks?)
Lily Krakowski on mon 3 feb 03
Poor, poor you! I have never had this problem with manganese, but I have
had it with other stuff. As far as I know you have three choices:
1. Have a major tantrum, scaring your family and friends, possibly your
dog. Your cat won't care. But kind people MAY decide you are so upset they
will relieve you of domestic chores for a week. Not a total loss.
2. Put the glaze through a strainer. Salvage the stuff that remains IN
the strainer and grind it in a mortar with a pestle. Lacking a proper m&p
you should achieve decent results by grinding it on a piece of thick glass
using the bottom of a jam jar or such--as long as it does not have a "foot".
WASH the stuff into your glaze test...it will take a few days to dry down to
application consistency.
3. Swearing loudly in some foreign language, mix your tests up well
and use them as is. You should get a pretty good indication of color, and
you certainly will get an idea if this base glaze works. MnO2 dissolves
easily in glazes so the lumps may dissolve in the fire....This is the route
I would take.
And then TALK TO YOUR SUPPLIER. I have no idea of mesh sizes but it seems
they sent you something that was not intended for glazes. Maybe it was for
adding specks to clay bodies.
Kristin writes:
> Flipping through _The Potter's Palette_, I decided I'd
> like to do a semi-grid of tests based on manganese
> dioxide and other oxides and one of RR/JH's base
> glazes.
>
> So I spent about 4 hours this weekend measuring out
> about 25 glaze batches (yes, I work slowly). Then I
> went back and started trying to add water and sieve.
>
> They won't make it through my 80-mesh sieve. In fact,
> I would guess these little chunks of manganese dioxide
> wouldn't make it through a kitchen strainer.
>
> I searched the archives for a reference to this, and
> have only found references and discussions about the
> toxicity of this chemical, which makes me think maybe
> I shouldn't be messing with it at all.
>
> But I have put the time into doing all of this
> measuring, the money in the chemicals, etc., so I'd
> like to follow through. Can someone tell me if
> there's a way to make these little chunks dissolve in
> water? All of the test batches have water added now.
> I thought maybe sitting for a while would help.
> Didn't, as far as I can tell.
>
> Thanks again, everyone.
>
> (I am not positive, but I think what I have is
> "24-40," I guess that refers to the size of the little chunks?)
>
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> Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
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Lili Krakowski
P.O. Box #1
Constableville, N.Y.
(315) 942-5916/ 397-2389
Be of good courage....
Paul Lewing on mon 3 feb 03
on 2/3/03 9:08 AM, Paul Herman at potter@PSLN.COM wrote:
> It sounds like you have GRANULAR manganese dioxide, from 24 mesh to 40
> mesh size. It's hard, and won't dissolve. What you need is the powdered
> form, manganese dioxide (cheap), or manganese carbonate (expensive).
I think Paul's right about this being granular manganese, but he and
everyone else is wrong about one other detail. No manganese compound (like
most of the other chemicals we use for glazes) will ever dissolve in water.
It would be a bad thing if they did, and we go to great lengths to find
materials that are insoluble.
You want the manganese particles to disperse, but they will never dissolve.
Paul Lewing, Seattle
Kristin on tue 4 feb 03
What compassion! Thank you so much for feeling my
pain. I'm afraid I already frightened the dog with my
expletives and my coworkers with my endless
description of wasted hours in the basment. But maybe
they weren't wasted . . .
I awoke with a start last night at midnight. I was
dreaming of flecks of color from following Lili's
(Lily's?) option #3 below, when suddenly it dawned on
me: what about option #4? Can't I just sieve out all
of those chunks and add powder instead?
Maybe all is not lost! Someone tell me if this won't
work?
I am learning so much. Thanks to all of you. This
little mistake would have been easily avoided with
some common sense prior to ordering, but it's a lesson
learned, either way.
- Kristin
--- Lily Krakowski wrote:
> Poor, poor you! I have never had this problem with
> manganese, but I have
> had it with other stuff. As far as I know you have
> three choices:
>
> 1. Have a major tantrum, scaring your family
> and friends, possibly your
> dog. Your cat won't care. But kind people MAY
> decide you are so upset they
> will relieve you of domestic chores for a week. Not
> a total loss.
>
> 2. Put the glaze through a strainer. Salvage
> the stuff that remains IN
> the strainer and grind it in a mortar with a pestle.
> Lacking a proper m&p
> you should achieve decent results by grinding it on
> a piece of thick glass
> using the bottom of a jam jar or such--as long as it
> does not have a "foot".
> WASH the stuff into your glaze test...it will take a
> few days to dry down to
> application consistency.
>
> 3. Swearing loudly in some foreign language,
> mix your tests up well
> and use them as is. You should get a pretty good
> indication of color, and
> you certainly will get an idea if this base glaze
> works. MnO2 dissolves
> easily in glazes so the lumps may dissolve in the
> fire....This is the route
> I would take.
>
> And then TALK TO YOUR SUPPLIER. I have no idea of
> mesh sizes but it seems
> they sent you something that was not intended for
> glazes. Maybe it was for
> adding specks to clay bodies.
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Snail Scott on tue 4 feb 03
At 07:57 AM 2/3/03 -0800, you wrote:
>They won't make it through my 80-mesh sieve. In fact,
>I would guess these little chunks of manganese dioxide
>wouldn't make it through a kitchen strainer.
Sounds like you got granular manganese, not milled.
Granular manganese is most often used for making specks
in clay bodies. Milled (a.k.a. powdered) manganese is
used as a colorant.
If you ordered milled manganese and got granular, you
should be able to return it to your supplier for an
exchange. If you can't, it may be possible to ball-mill
the stuff, but I've never tried it. Unless you got a
whole lot of it, I'd just call it a loss, order some
milled manganese, and start over.
Manganese (either dioxide or carbonate) is a useful
colorant, versatile, well-behaved and generally
predictable. Don't give up on it.
A few suggestions, though: wear disposable latex gloves
when handling it or your cuticles will be black for a
week even if you think you are careful! (And of course,
don't breathe the dust or fumes.)
-Snail
Marianne Lombardo on tue 4 feb 03
Kristin,
I think you could still add the powdered manganese and you will likely get
the colours you wanted, with little flecks or streaky flecks from the
granular throughout it.
Sometimes I toss in some granular manganese in some of my glazes because I
like the dark flecks that show up, and I haven't noticed it doing anything
to the colour of the glaze. When I do this I use small amounts of the glaze
and add the granular manganese, stir it up and use it right away. Have to
keep stirring though.
Marianne Lombardo
Omemee, Ontario, Canada
email: mlombardo@nexicom.net
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