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using mason stains to stain clay body--food safe?

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I love staining porcelain clay bodies with mason stains and then combining colors. However, before I go crazy and start ordering a bunch of random colors, I want to make sure that I only use food safe stains since these will be used in food bowls. I am wondering how I verify which stains can be used to stain clay bodies that will be used for functional ware. The people at the place where I buy from in Dallas, Texas assured me that if I am staining the clay body then ANY stains that I use will be food safe. This seems odd to me that ALL stains are food safe. There are some with cadmium which I know is a concern in glazes. (For this reason, I don’t use any glazes with cadmium since I like to err on the side of caution.)

However, after researching on the mason website and looking at the material safety data sheets for various stains I don’t see anywhere on how to find out which stains actually are food safe. And I can’t seem to locate a list of ingredients to stay away from.

Has anyone run into this and found a useful resource? Should I just stay away from the ones that use cadmium? Or are those safe to use since I am staining the body? I plan on firing to cone 6-10 with a food safe clear glaze---I will have to play around with various cone firings to see which bring about the most vibrant colors. Thanks in advance for any info.

I should add that I willl send samples to a lab to be tested before selling any as “food safe.†I am just trying to figure out where to even start.

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The Bailey Pottery site has pretty good info listed on Mason Stains and their recommended use, composition, which are recommended as body stains, what to use/avoid in glazes, etc.

 

http://www.baileypottery.com/glazes/masonstains1.htm

 

Other suppliers may have similar info.

 

You seem to be headed in the right direction by doing your research up front and planning to do testing to make sure your wares are "food safe". Also check out the Hesselberth and Roy book, Mastering Cone 6 Glazes, for their discussion on the characteristics of a durable glaze and what to check for when you do submit an item for lab testing.

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Mason stains are not chemicals ... They are fritted colorant mixtures processed to be stable.

The only danger comes from inhaling the powder while mixing or sanding.

The recommendations for use on their site are about the predictability of color results in each situation.

 

As to the encapsulated stains .. like anything else, they must be fired and glazed properly.

 

Mason stains are widely used in all manufacturing areas because they are stable and can be fired to high temperatures without fading.

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The reason a stain is safer in the clay than in a glaze is that the clay will help to encapsulate any colorant. I do agree with you encapsulated or not, I'm not a fan of cadmium.

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The Ceramic Supply of NY & NJ catalog is one of the best resources I’ve ever seen for a wide selection of the Mason stains and glazes. The catalog is on line and is an encyclopedia of ceramic making information. They also list which of the Mason stains is suitable for body stains. This is a gem of a reference. Here is the link to the catalog it is a .pdf file and is 138 pages it is a good idea to save it to a flash drive and/or in your documents file for quick reference. http://www.7ceramic....y%20Catalog.pdf

 

As with all catalogs double check information listed as there maybe typos.

 

The Ceramic Supply of NY & NJ's website is http://www.7ceramic.com

 

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i will bookmark these links and look thru them to familiarize myself. i called the people at mason stains yesterday and they were really helpful, as well. the lab tech i talked to there said the same--they are all food safe--just do not inhale the powder form. thanks for all the great info!

regards,

rach

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Another thing to note is that the stains designated as "body stains" are the ones Mason guarantees will work in clay bodies. There are many others that also do well in some clay bodies but you have to buy small amounts and test fire them. The reason they cannot guarantee all of them is that clay contains materials that will react and change the final color. I once had a pink stain fire to a nice pale green ... You always have to test.

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i will bookmark these links and look thru them to familiarize myself. i called the people at mason stains yesterday and they were really helpful, as well. the lab tech i talked to there said the same--they are all food safe--just do not inhale the powder form. thanks for all the great info!

regards,

rach

 

 

I'm doubtful about them all being food safe. Even though Mason says they are, I would test them. I've seen metallic oxides, such as copper as cobalt, migrate from a clay body through a glaze and render it unsafe for food. It's all going to depend on the amount of stain used in the body, as well as the formula of the glaze. Just because the oxides in the stain are already fired together, it doesn't mean that they are no longer dangerous. Copper can still be leached from a glaze even if it's part of a stain, and many oxides will migrate from the body into the glaze. Test!

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