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Two Questions About Manganese Dioxide Use


mrcasey

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1.  I'm interested in putting together the Oatmeal glaze from the book Mastering Cone 6 Glazes.

The recipe calls for manganese dioxide.  I might have some 60 mesh MgO2, but I'm wondering

if that's too large of  a mesh size.  Do I need to order the 200? 

 

2.  I do pottery at a community center.  A 10' X 10' kiln room is attached to the studio.  In addition

to a fan sucking air out of the room, there is an air vent on the kiln that expels air through a

vent to the outside.  I'm planning on using the MgO2 only in small amounts for glazing - less than 10%.

The administrator isn't really a ceramics person and lets us have fairly free reign.  I want to live

up to the trust she's placed in me by not creating an unsafe environment.  Is it safe and appropriate for

me to be using manganese dioxide glazes in a community studio?

 

thanks,

Casey

 

 

 

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Go with a finer mesh, it will disperse/mix better in the glaze. Hamer and Hamer (The Potter's Dictionary of Materials and Techniques) suggests 4% for glazes; they cite 10% for slips.

 

Manganese dioxide is toxic; so it needs safe handling. Get a copy of the MSDS and familiarize yourself with its contents so you can make an informed decision. As long as you follow good safety precautions, e.g., manganese dioxide only used in a glaze kitchen by persons trained to use materials, appropriate respirator worn when working with the material, etc., you can minimize risk. You might also note on the glaze bucket if the glaze includes manganese dioxide so others can be aware of its presence.

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Manganese Dioxide enters the body by the skin contact, ingestion, and breathing fumes. Use precautions when handling it. Also you should make sure to use low percentages that will not leach. Glazes should be fired to maturity. 10% is over saturation for a metal oxide and would be unstable. If unsure , get it tested.

 

Marcia

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Guest JBaymore

Manganese creates fumes (tiny sub-micron particulates) in firing.  These can get into the environment in the kiln room IF the vent system is not working properly.  So you are depending on the vent system to prevent this.  If you KNOW the vent is good (tested by someone who knows what that means) ........ then that is not an issue.

 

10% manganese dioxide is almost for certain NOT suitable for any food contact. Are you sure about that percentage?   If it is 10%, likely this is a gunmetal black or gray surface ...... and the texture is cause by precipitation of compounds on the glaze surface that are NOT tied into the glass matrix.

 

Get this leach tested before using it on food contact surfaces.

 

As was said.... get the MSDS and learn to read it.

 

best,

 

..................john

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Because one of the main thrusts of Mastering Cone 6 Glazes is concerned with the analysis and

creation of food safe glazes, I'm fairly confident that the oatmeal glaze appearing therein is food safe.

Although I don't have the text on hand, I'm fairly sure the MgO2 is around 4%.  My only real

concern is with the firing fumes.  Is there a way for me to test the ventilation system?

 

thanks for all the input,

Casey   

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  • 4 weeks later...

A month-old thread, but just to note that the chemical symbol for Manganese is "Mn" not "Mg" -- "Mg" is Magnesium, and it's oxide would be MgO not MgO2

 

A crude test of the ventilation system could be accomplished with a smoke-producing smoldering splint of wood -- where does the smoke get drawn to? 

 

I would want to be sure of the balance between the room exhaust fan and the kiln vent fan; where is the make-up air coming from? in the extreme case, a very powerful room fan could be drawing air in through the kiln vent despite the best efforts of the kiln vent's blower...

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Oops - It's Mn indeed.  I don't know Jack about chemistry, but John Hesselberth gives the formula as MnO2.

That formula also pops up on various web pages when I google the term manganese dioxide.    

            

I'll give your vent test a try.

 

Casey

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Manganese DIoxide...MnO??    Can't remember that far back but di usually alerts one to the fact htere are 2 ions of oxygen to one eg Carbon Dioxide CO2 though the valency of the Manganese  is what?.

Tooo far in the past will check it out though.

Tim You need to :) edit your post, though we all know what you mean.

Hungry here so maybe tetchy.

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Babs,  Yes, Manganese Dioxide is MnO2  but Casey was writing MgO2 which is non-sensical because Mg is the chemical symbol for the element Magnesium -- not Manganese -- and Magnesium (Mg) will only ever have a valence of +2 so it's oxide will always be simply MgO, Magnesium Oxide, no "di-" prefix needed.

 

ETA: this thread is, of course, about Manganese Dioxide (MnO2), not Magnesium Oxide (MgO), which is exactly what I was trying to clarify. For those who don't work with the Periodic Table and the Chemical Symbols for the elements on a regular basis, it can be easy to get confused, especially with elements that have similar-sounding or similarly-spelled names (like Manganese and Magnesium) and thus similar Chemical Symbols, as well as with elements whose Chemical Symbol has no relationship with the element's common name in English (like lead, gold, silver, antimony, tin, etc...).

 

Potters are called potters because they make pots, obviously. Anyone know why plumbers are called plumbers? <_<

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Plumbarius. Eventually shortened to plumber. Latin lor lead plumbum... During Roman Empire pipes were made of lead along with other things. Is there a word for the accompanying plumbum for inter gluteal cleft?

 

Now to figure out how to make dark brown clay without Mno2, manganese dioxide.

 

Would mason stains or the like be healthier?

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Mr Casey!!!EVERYONE knows that plum is a fruit!!

Plumb on the other hand means of course, straight, so all plumbers are straight trustworthy people who would never charge huge prices for an hour's work..

Pb well, of course, personal best.

Which brings us right back to potters.

ThInk I'll go soak in a bath of Mg S04 or was that Mn...

Seriously. Partners of miners working at the Manganese mines were afflicted, as were their partners because of exposure to this nasty.

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Potters are called potters because they make pots, obviously. Anyone know why plumbers are called plumbers? <_<

Right so that is why we hung out with the likes of BEnzine thro' highschool, we were never gonna have to study the periodic table and the positive and negative ions and quarks and coefficients of expansion and dream of hte unknowns. we were gonna just make pots.

No need to dabble with the unknowns and knowns....

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