David Hendley on mon 28 sep 09
First of all, only a few stains, those with cadmium, are
encapsulated, which means only high-fire reds, oranges,
and yellows.
Fooling with cadmium is serious business. The manufacturers
state that they are safe because of the encapsulation, as long
as they are not ball milled.
If the glaze covering your colored slips is a craze-free glossy
and technically good glaze, that should also make for a
safe combination.
So, bottom line, theoretically, your fired pieces should be
perfectly safe for the user of the piece. To be absolutely
assured that all is OK, the only proof positive thing to do is have
the slip-glaze combination tested at a ceramics testing lab.
I have been using the encapsulated stains for many years, but
choose to only use them on outside, non-food bearing surfaces.
I would rather not worry or submit samples to testing.
Also remember that there is also the health of the potter to
be concerned about, so practice excellent studio hygiene
if you use the cadmium stains. Do not allow any spills to dry
and create dust, wash your hands after using, etc.
David Hendley
david@farmpots.com
http://www.farmpots.com
----- Original Message -----
Through the little bit of research I have done today concerning my glaze, I
have started thinking about whether the Mason stains I use in my colorful
slips might be toxic to the consumer.
I have always thought that since the Mason stains are encapsulated, and
should therefore be safe or safer than chemicals in free form, and because =
I
use a glaze on top of the stains, it would be OK.
How safe are Mason stains on a fired, glazed piece (assuming the glaze is
good)? I am especially worried about those that contain cadmium.
Elisabeth Maurland on mon 28 sep 09
Through the little bit of research I have done today concerning my glaze,=
=3D
I
have started thinking about whether the Mason stains I use in my colorful=
=3D
slips might be toxic to the consumer.=3D20
I have always thought that since the Mason stains are encapsulated, and
should therefore be safe or safer than chemicals in free form, and becaus=
=3D
e I
use a glaze on top of the stains, it would be OK.
How safe are Mason stains on a fired, glazed piece (assuming the glaze is=
=3D
good)? I am especially worried about those that contain cadmium.
Anne Elisabeth Maurland on tue 29 sep 09
Hi David,
I am going to send a sample to a ceramics lab. I believe the glaze I'm
using is not so good, so I am going to try new glazes and do the
necessary testing.
Most of the time, I use the Mason stains on outside surfaces, but I
have sometimes been tempted to use them on the insides as well. I can
stop doing that without changing my style too much.
I have always been more careful with the cadmium stains than with the
others - using a mask and gloves when handling.
Thank you for your informative post!
Elisabeth
On Sep 28, 2009, at 11:39 PM, David Hendley wrote:
> First of all, only a few stains, those with cadmium, are
> encapsulated, which means only high-fire reds, oranges,
> and yellows.
> Fooling with cadmium is serious business. The manufacturers
> state that they are safe because of the encapsulation, as long
> as they are not ball milled.
> If the glaze covering your colored slips is a craze-free glossy
> and technically good glaze, that should also make for a
> safe combination.
>
> So, bottom line, theoretically, your fired pieces should be
> perfectly safe for the user of the piece. To be absolutely
> assured that all is OK, the only proof positive thing to do is have
> the slip-glaze combination tested at a ceramics testing lab.
>
> I have been using the encapsulated stains for many years, but
> choose to only use them on outside, non-food bearing surfaces.
> I would rather not worry or submit samples to testing.
> Also remember that there is also the health of the potter to
> be concerned about, so practice excellent studio hygiene
> if you use the cadmium stains. Do not allow any spills to dry
> and create dust, wash your hands after using, etc.
>
> David Hendley
> david@farmpots.com
> http://www.farmpots.com
>
>
>
> ----- Original Message ----- Through the little bit of research I have
> done today concerning my glaze, I
> have started thinking about whether the Mason stains I use in my
> colorful
> slips might be toxic to the consumer.
> I have always thought that since the Mason stains are encapsulated, and
> should therefore be safe or safer than chemicals in free form, and
> because I
> use a glaze on top of the stains, it would be OK.
>
> How safe are Mason stains on a fired, glazed piece (assuming the glaze
> is
> good)? I am especially worried about those that contain cadmium.
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