Dennis Mummert on sun 4 feb 01
After reading the many responses to manganese in glazes. I'm concerned with
the clay I use and work with everyday. It's a cone 6 clay that produces
beautiful specks and looks gas fired even though I fire in an electric kiln.
The specks are a result of the manganese in the clay. I've made and sold
functional dishes set with this clay for several years. I always use a
dinnerware safe glaze.
My question is, is it safe to handle day after day.
According to ASTM D4236 it is. If you listen to Monona Rossol (sorry,
spelling...), you'd have to use an environmental suit to even think about
clay. However safe manganese is to handle, avoid ingestion and inhalation,
because it ISN'T safe to do either of those. Wetmop messes, and do NOT sand
greenware unless you do so under a fume hood or wear a metals rated
respirator. Manganese (dioxide) is not particularly soluble in neutral pH
water, though.
I throw all the pieces I
make and I don't like to ware rubber gloves when working. Do you consider a
clay made with manganese dangerous to the skin?
I do ware a mask when cleaning my studio or sanding greenware. When the
kiln
is on the fumes are so prevalent that no one could work in the same area.
Thanks Debbie
Kilns are another kettle of fish. Manganese does outgas, about like most of
the other stuff we use. Don't expose yourself to kiln gasses unnecessarily.
If the kiln is in the house, or in the same room you use to throw, move it.
Neurological damage is known to occur in people who allow excessive amounts
of manganese into their bodies. It is not reversible.
Glazes, particularly used on functional ware, need to be tested by a testing
laboratory if speckle clay is involved, as manganese alters the glaze away
from the manufacturer's stated use conditions.
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vince pitelka on sun 4 feb 01
> My question is, is it safe to handle day after day. I throw all the
pieces I
> make and I don't like to ware rubber gloves when working. Do you consider
a
> clay made with manganese dangerous to the skin?
> I do ware a mask when cleaning my studio or sanding greenware. When the
kiln
> is on the fumes are so prevalent that no one could work in the same area.
Debbie -
The danger is not through absorption, because the particles are too coarse,
and they are insoluble. Besides, the manganese they use in claybodies is
usually the granular stuff, which doesn't even end up as dust. But you are
of course right in ALWAYS wearing a good dustmask whenever making dust.
It scares me though when you say that the kiln fumes are so prevalent that
no one could work in the same area. Get a good vent system and install it
ASAP. You do not want that stuff impregnating into all the surfaces in your
studio. The cost of a good vent system is miniscule in comparison to the
risks without one.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Debbie Smith on sun 4 feb 01
After reading the many responses to manganese in glazes. I'm concerned with
the clay I use and work with everyday. It's a cone 6 clay that produces
beautiful specks and looks gas fired even though I fire in an electric kiln.
The specks are a result of the manganese in the clay. I've made and sold
functional dishes set with this clay for several years. I always use a
dinnerware safe glaze.
My question is, is it safe to handle day after day. I throw all the pieces I
make and I don't like to ware rubber gloves when working. Do you consider a
clay made with manganese dangerous to the skin?
I do ware a mask when cleaning my studio or sanding greenware. When the kiln
is on the fumes are so prevalent that no one could work in the same area.
Thanks Debbie
Ron Roy on tue 6 feb 01
Hi Debbie,
I would think there is some powdered manganese with the granular but I
don't think you should not use the clay.
Maintain good dust control in your studio - a central vac system that blows
the dust ourside is the best way to do that - and keep the floor clean of
scraps and trimmings so they are not turned into dust.
The exposed manganese - where not covered with glaze will probably off gas
during a firing some amount - make sure the kiln is well vented.
Manganese is not a problem through skin contact and not a problem through
ingestion so the dinner ware is not a concern. If you want to know if the
glaze is durable have it tested for you own peice of mind.
RR
>After reading the many responses to manganese in glazes. I'm concerned with
>the clay I use and work with everyday. It's a cone 6 clay that produces
>beautiful specks and looks gas fired even though I fire in an electric kiln.
>The specks are a result of the manganese in the clay. I've made and sold
>functional dishes set with this clay for several years. I always use a
>dinnerware safe glaze.
>My question is, is it safe to handle day after day. I throw all the pieces I
>make and I don't like to ware rubber gloves when working. Do you consider a
>clay made with manganese dangerous to the skin?
>I do ware a mask when cleaning my studio or sanding greenware. When the kiln
>is on the fumes are so prevalent that no one could work in the same area.
>Thanks Debbie
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
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