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DanG

Vanadium and food safety?

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I was told a body stain I am wanting to use is food safe when fired. I have never used Vanadium before and although I understand its toxic in its unfired state, I was wondering what the feeling is about using it in a Zirconium stain formula?

 

Its from Walker Ceramics in Melbourne:

FW5307 Deep Sky Blue - V Zr (Vanadium, Zirconium dioxide)

 

 

This is another stain possibilty:

FW5359 Lavender - Co Cr Sn Zn (Cobalt oxide, Chromium oxide, Tin Oxide, Zinc oxide)

 

How does this one compare to the Vanadium in terms of food safety?

 

Is Vanadiuim any more toxic than using Cobalt?

 

With thanks,

Dan

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You don't say what temp you are firing to. I am in the U.S.A. and use Mason and Spectrum stains. It's my understanding from their literature that zirconium encapsulated stains are food safe when fired properly. Please be aware that the cobalt is a heavy metal and can leech if fired incorrectly. Your supply company should have a hot line or customer service that will answer your questions.

 

P.S. I just went over to the Walker site. These stains look like the equivalent of Mason Stains. I personally would have no problem using them. Just be sure to follow the information guidelines provided.

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I am using them as a body stain in casting slip called MFQ (mid fire quartz). Glaze firing will probably be cone 4 to 5. I havent had a chance to test this in the kiln yet but I will be aiming as high as I can to achieve full vitirification.

 

The funny thing is that I can find NO official information line, no one who can certify these are food safe and theres no official advice on the matter here in Australia.. Its been very frustrating! I have met with some stain manufacters and thier customer relations know nothing whatsoever in relation to food saftey.. he had to write to a former boss who gave me the thumbs up but I still cant get any kind of official certification of saftey.

 

Do you think I should only trust Zr encapsulted stains? Do you think a Zr stain would be ok even without a clear glaze over the top?

 

I have been told that Cobalt is ok when combined with Si and Al as long as its under a clear glaze. I havent heard anything about Cobalt leeching under certain firing conditions, so Im keen for more information about this.

 

I guess the best way is to have the pieces tested for leeching, which I will do.

 

with thanks,

Dan

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Guest JBaymore

No manufacturer indemnifies the end user for any liability whatsoever. I don't know Austrailian law, but under US law, the responsibility for any potential legal issues is the respopnsibility of the end manufacturer (as in you, the artist). So even if the supplier says to you "food safe", that really means nothing to you.

 

There are also so many ways of using and firing such materials that it would be basically imporssible for a supplier to formally certify their raw material product to be "safe" across the board. At the most, they can say that someinghas been tested in such and such an manner under such and such conditions, and hase been found to exhibit these specific porperties as to a criteria like "leaching of toxic materials".

 

In ceramics it is always a "your mileage may vary" situation on the end use of raw materials.

 

When you start using products with known potential toxicological issues in your products, you'd best understand what it is that you are using very well. If you feel that the risks are there, you should have the necessary testing done yourself.

 

Otherweise you are open to potential liability, both ethical and legal.

 

If you are disbursing such a stain throughout a clay body, I would think that the potential issue is worth researching carefully. And rememebr that the clay DUST in the workshop is then going to carry that smale material in it also.... which is a potential health concern for everyone in the workshop (beyond the usual issues of simply carcinogenic microcrystaline silica dust).

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