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monona - toxicity of mason stains

updated sat 14 mar 98


Vince Pitelka on thu 12 mar 98

>Get the ingredients from Mason--if they'll tell you--and avoid the highly
>toxic metals such as cadmium, lead, antimony, chrome, nickel, antimony, etc.
>If they wont tell you, you have no way to judge.

Monona -
I'm curious about this, and would like to hear your opinion. Since Mason
stains are all fritted mixtures, the toxic metals are to some extent
encapsulated in glass. With that in mind, knowing which materials are
present wouldn't necessarily tell us how toxic the raw stain is. To what
degree does this encapsulation shield us from toxic metals in raw Mason Stains?
- Vince

Vince Pitelka -
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166

Louis Katz on fri 13 mar 98

Hi Vince,
It is important to differentiate between fused, sintered, and melted.
I'll leave it up to someone else for final dictionary definition, but
Mason stains are far from being melted together and then ground up. They
are not frits, and most (all?) have too little silica to make good
glasses I believe.
Melting lead and tin together until they are melted and mixing them
gives you solder, depending on the mixture the lead remains anywhere
from soluble to very soluble in tap water. Most stains are not heated to
the point of being liquids and probably maintain more of the properties
of the individual components.
Sintering is just heating up two materials until they stick together.
Some of the material may melt to form the binder but the bulk of it
remains unchanged.
Fused as I use it refers to a more complete sintering. To be melted a
material must become liquid, although not necessarily very fluid.
I await more education