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Joseph F

Mason Inclusion/encapsulated Stains Containing Cadmium For A Glaze

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I did a forum search and many google searches, but I could only find things about putting them into the clay body, which is very different.

 

Does anyone use these? There is an orange one that I really would like to tinker with for the outsides of some of my pots as a highlight color. 

 

I haven't convinced myself that I need the color enough to risk using the stain. I have been reading everything I can about encapsulated stains and apparently they are used by industry. I am no where near........ confident enough to think I am producing the exact results as industry does, so it makes me nervous. I have a hard time understanding that even industry is using them. However I have seen a lot of ceramics lately with really brilliant bright colors like these. I also have seen many commercial glazes that have brilliant oranges like this. So I have to presume they are using some type of encapsulated stain to achieve these colors?

 

My other idea was just to buy a pint of a bright orange commercially and use it for my surfaces. I don't like doing this as much because of course I don't know what is in the glaze and I can't tinker with it to make it play nicely with my firing schedule etc. However I feel more confident that they have formulated a glaze and provided proper instructions for firing it correctly that I can do and verify pretty confidently with orton cones.

 

Whats the verdict? 

 

1. Stay away. 

2. Mix and test, then send away the result I want to use for testing.

3. Not worry about it since its not on a food surface. Do people eat off the side of mugs?

 

So far I have always used food safe liner glazes, and even on the outside of my pots I use very low amounts(.5-2%) of metallic oxides like copper or cobalt.

 

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Joseph,

 

According to William Carty (Alfred glaze guru) the encapsulated cadmium stains like the Cerdec one have the cadmium well "tied up".  So that will allow the production of some bright red based colors at just about all firing ranges and atmospheres.  And without significant release.  I am not sure what he thinks the risk to the POTTER is in handling the dry material though.  He did not comment on that.  Just fired product.

 

The stains are relatively new.  So not much time to do employee occupational health studies on it.  Ask for an MSDS.

 

Here is an issue to consider. 

 

The US laws (FDA and State of California) are very specific about the presence of cadmium in ceramic wares.  They do not take into account HOW the cadmium is in the glazes, under-glazes, enamels, slips, and so on.  Just that it is there.   If you are making wares for sale with cadmium compounds in the production, the laws apply.  Which means to be legal, you have to follow the standards.  To follow the standards you HAVE to know the release numbers, and you have to do formal lab testing to know that.  And you need to keep records.

 

Anything that is used for food or reasonably CAN be used for food is covered.  Otherwise... you need a fired on specific statement..... or a hole in the bottom that prevents it holding any liquid-y stuff.

 

You are correct that you are seeing bright reds and the like all the time lately... and I am guessing that about 95% of the studio artist people using them are NOT following the laws.  Some because they do not have a clue about the laws, some because they do not know cadmium compounds are in the things they are using, some because they think because it is in an under-glaze or slip it is not regulated, and some because they know and simply don't care.  Some say "governmental over-reach".  Some poo-poo the toxic question altogether.

 

So if you do it, to be fully legal.... you have to understand the laws and comply.

 

Will you get "caught" if you don't?   Who knows.  Likely small risk.  But............... (Some day I'll talk about the lead glaze studio potter witch-hunt the FDA went on here in NH about 20 yeas ago.) 

 

Informed consent. ;)

 

best,

 

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

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John

 

As always thanks for the perfect response. I will continue to not use these encapsulated stains. I have no intentions of breaking any law and worrying about any of this just seems absurd considering how many other beautiful colors can be made without using this specific stain. I will look else where for a less bright red orange color and just make due. 

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Double check the number on the stain, but some of the yellows and oranges are praseodymium or yttrium based.

https://digitalfire.com/4sight/material/stains.html

My IRL supplier has a phamphlet from Mason that categorizes the stains by the colourants used to make them (so you can use them in an optimal base glaze), but I can't find the same thing on their website. It may be available upon request.

 

Edit: here's the encapsulated praseodymium- based yellow at cone six, cut with gerstley borate and washed thinly onto a white slip. It sadly burns out in reduction at cone 10, or id be buying stock in the company.

post-63667-0-34387100-1453611485_thumb.png

post-63667-0-34387100-1453611485_thumb.png

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Joeseph, Diesel;

I am currently working on adding colour to my glazes as well. Not thinking an entire red glaze, just high lights. See my gallery for a chicken plate with a nice red comb. I know the inclusion stains from U.S. pigment work at cone 10 reduction, but I don't know if I want to spend the money for something that may or may not work for me.The red on the plate is a Mason stain with Gerstly applied to the unfired white glaze.

There was talk in a previous post about a low-fire yellow underglaze that went to cone 10 applied on top of the glaze;

Amaco intense yellow V-308, or also V-391.

These came from Mark Cortnoy's assistant.

Sadly for me, they are both lead based, and I am a functional dude.

Let me know how far you get on your research.

I will dig up the name of that Mason stain red.

TJR.

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Joseph,

 

According to William Carty (Alfred glaze guru) the encapsulated cadmium stains like the Cerdec one have the cadmium well "tied up".  So that will allow the production of some bright red based colors at just about all firing ranges and atmospheres.  And without significant release.  I am not sure what he thinks the risk to the POTTER is in handling the dry material though.  He did not comment on that.  Just fired product.

 

The stains are relatively new.  So not much time to do employee occupational health studies on it.  Ask for an MSDS.

 

Here is an issue to consider. 

 

The US laws (FDA and State of California) are very specific about the presence of cadmium in ceramic wares.  They do not take into account HOW the cadmium is in the glazes, under-glazes, enamels, slips, and so on.  Just that it is there.   If you are making wares for sale with cadmium compounds in the production, the laws apply.  Which means to be legal, you have to follow the standards.  To follow the standards you HAVE to know the release numbers, and you have to do formal lab testing to know that.  And you need to keep records.

 

Anything that is used for food or reasonably CAN be used for food is covered.  Otherwise... you need a fired on specific statement..... or a hole in the bottom that prevents it holding any liquid-y stuff.

 

You are correct that you are seeing bright reds and the like all the time lately... and I am guessing that about 95% of the studio artist people using them are NOT following the laws.  Some because they do not have a clue about the laws, some because they do not know cadmium compounds are in the things they are using, some because they think because it is in an under-glaze or slip it is not regulated, and some because they know and simply don't care.  Some say "governmental over-reach".  Some poo-poo the toxic question altogether.

 

So if you do it, to be fully legal.... you have to understand the laws and comply.

 

Will you get "caught" if you don't?   Who knows.  Likely small risk.  But............... (Some day I'll talk about the lead glaze studio potter witch-hunt the FDA went on here in NH about 20 yeas ago.) 

 

Informed consent. ;)

 

best,

 

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

 

Before I started using prepared underglazes I looked into the MSDS sheets from various manufacturers. Speedball ug's were one of the lines I was looking at. Nothing on the MSDS listed cadmium (encapsulated). It took a few emails but I talked to their lab person and was told orange, yellow orange, melon, red, burgundy, violet, pink and purple contain it. So 8 out of 24 of their ugs contain it and nothing on their MSDS about cadmium. Under the hazardous ingredients section of the it it states “noneâ€. Hard to comply with the laws when the manufacturers hide the ingredients. (Speedball)

 

http://www.speedballart.com/cms_wfc/uploads/54.pdf

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Before I started using prepared underglazes I looked into the MSDS sheets from various manufacturers. Speedball ug's were one of the lines I was looking at. Nothing on the MSDS listed cadmium (encapsulated). It took a few emails but I talked to their lab person and was told orange, yellow orange, melon, red, burgundy, violet, pink and purple contain it. So 8 out of 24 of their ugs contain it and nothing on their MSDS about cadmium. Under the hazardous ingredients section of the it it states “noneâ€. Hard to comply with the laws when the manufacturers hide the ingredients.

 

http://www.speedballart.com/cms_wfc/uploads/54.pdf

 

 

Common story I hear.

 

The overview of the accuracy of MSDSs is lax to say the least.  If you check around with the various manufacturers/suppliers, you can find ones that are totally laughable (if it weren't serious business). 

 

They often look for every loophole to NOT show what is in there.

 

Stuff like the AP Nontoxic labels are also often laughable in how they are applied.  Yes.... wet clay is not readily respirable... so the non-toxic label can certainly apply... as long as you ONLY look at the material in the wet state.  let it dry out and get it airborne... and it is a known human carcinogen ... due to the free silica.

 

So yup... does not surprise me in the least.

 

So use your knowledge of ceramic chemistry to help guide you along.   Blood or fire-engine red at cone 9 (other than copper in reduction)?  It is a great guess cadmium is involved.  Ditto at cone 6.  Getting down to 04.......... probably.  If not cadmium there.... probably has lead.  Getting down to 015... maybe could come from gold chloride... but that is a muddy red.  Maybe iron... but then for sure lead.

 

The important point for people who SELL work is that (legally) YOU are responsible for YOUR wares.  The glaze materials supplier is NOT. ( They do not indemnify.)  If you ever had a liability issue, folks will be going after YOU.  It is only later that you could try to make a case against the supplier.

 

Best reason to mix your own glazes, slips, and so on.  At least some control over what might be in there.

 

best,

 

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

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Totally agree John. I think the concern lies with people who are just starting out who don't know what they don't know. Also, the cadmium inclusion stains are turning up in glazes that are getting more difficult to just look at and know they contain it. An example would be Coyote's Butterscotch Shino.

mbg086.jpg

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The "good news", if you want to call it that, is that.......

 

A. the encapsulated stains are supposedly stable

 

B. the less obviously red the glaze is, the lower the percentage of cadmium compounds

 

Of course if it is there...... the laws apply.  So it is a Catch 22 for the potter.

 

best,

 

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

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Do the yellows that contain cadmium have less of it than the bright reds? Mason's 8479 Sunshine (yellow) has the same range of cadmium sulfide  as the Mason reds. (8-15%). So would the yellow be on the low end of that range?

 

Moot question I know, just curious.

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Min, my understanding of the variation in colour is that it's not from concentration of the pigment itself, but the variation of the pigment's chemical makeup.  It's not just cadmium sulphide (which is yellow by itself), but also sulfoselenides (orange to red), and selenides (red).

Min and JBaymore like this

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Tyler, sorry I was just trying to make a complicated question simple. Selenium range is the same (1-10%) for all of the Mason Cd stains, again just pointing to John's comment about the usefulness of MSDS. In fact all the ingredients in the "Composition / Information on Ingredients" section have the exact same range for all the Mason Cd stains.

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Tyler has it on the color development issue.  So ... can't really say.  Not enough info available from the makers.  They don't want to give out TOO much information.... proprietary formulations.

 

Sometimes for the MSDSs a company puts out, they just lump together ALL of the products in a "line" as some sort of "generalized" sheet that covers them all.  When that is done, the sheets can be quite misleading.  Don't know if mason is doing that.  Also see if MASON is the people listed as preparing the sheets you have (top of form or extreme bottom of form).... sometimes I've seen the supplier make them up... not the manufacturer (which seems to be not the way it should be).

 

best,

 

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

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I don't know if it is still the case, but when I first read about the encapsulated stains I remember that there was advice:

- on things to avoid in the base glaze (to reduce the solubility of the encapsulation)

- that the base glaze should contain at least a certain amount of zircon (ditto)

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