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Speckled Clay without Manganese? Anyone use a safer option?


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I'm having a hard time finding a speckled clay without manganese.  Anyone have any suggestions?  I've searched the SDS sheets of Standard Ceramic, Laguna, Minnesota clay co and Amaco.  The best I can tell is that Amaco may not use it in their 480M and 48M with grog but their SDS sheets don't  seem to list all the ingredients so I'm skeptical.  I can't tell from this list (below) what would be causing the blooming speckles?  It also seems like they are only listing the top 5 ingredients by weight. 

  • Hydrated Aluminium Silicate 10-30%
  • HYDROUS ALUMINIUM SILICATE 10-30%
  • Fireclay 10-30%
  • Hydrous Aluminium Silicate 10-30%
  • silica 5-10%

Anyone have any recommendations for a safer speckled clay?  Or does that not exist? 

AMACO 480M STONEWARE W-O GROG - SDS4882.pdf

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Speckled clay for electric kilns will always use manganese, because it melts in electric kilns.  In a reduction firing any red clay can speckle, so maybe try changing your firing style?

As far as safety is concerned, kiln fumes is the only real hazard.  And kiln fumes are a hazard whether there's manganese in the kiln or not.  

 

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3 hours ago, Mark C. said:

Whats wrong with manganese???It makes the speckle

Kiln fumes as noted is the issue and its a small one at that -get a vent and do not worry.

 

 

I know they a make beautiful surface but i am under the impression that the fumes are extremely dangerous compared to some other materials off-gasing in the kiln.  So if it's possible to avoid both the dust and the fumes and get similar results then why wouldn't you? 

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2 hours ago, Callie Beller Diesel said:

Fireclay often has a lot of iron bits, or other large, visible impurities. That’s likely the source of the speckle. 

Okay good to know! That must be it then.  Thank you!

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4 hours ago, liambesaw said:

Speckled clay for electric kilns will always use manganese, because it melts in electric kilns.  In a reduction firing any red clay can speckle, so maybe try changing your firing style?

As far as safety is concerned, kiln fumes is the only real hazard.  And kiln fumes are a hazard whether there's manganese in the kiln or not.  

 

Change the firing style like switch to reduction? That is pretty impossible in my scenario so finding a less toxic clay would be easier for me if it exists. 

And you're right about kiln fumes being an issue no matter what.  I think the extra warnings on some materials just spook me a bit and make me feel like, "Am i doing the safest thing here and is it worth it? " 

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5 minutes ago, AngelaV said:

Change the firing style like switch to reduction? That is pretty impossible in my scenario so finding a less toxic clay would be easier for me if it exists. 

And you're right about kiln fumes being an issue no matter what.  I think the extra warnings on some materials just spook me a bit and make me feel like, "Am i doing the safest thing here and is it worth it? " 

I get it, you can try wedging ilmenite into white clay, but the speckles are lackluster in my experience.  Manganese is sort of where it's at.  

Skip to the second paragraph here to read on the safety issues of speckled bodies.

https://digitalfire.com/hazard/manganese+in+clay+bodies

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Moist clay bodies with manganese are certified non-toxic, which means that they're non-toxic in the moist form. The dry dust that happens in the studio is not non-toxic, but you're going to be breathing in a lot more silica dust than manganese dust, and the silica is an issue. So as long as you follow basic hygiene practices in the studio the dust from manganese will not be an issue. In the firing, if your kiln is vented then the fumes will not be an issue.

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