Lesley Alexander on sun 17 jul 11
Great to get warm tones using cadmium inclusion stains, but what is their
record so far? For food, I've been timid, only using stains under a good
clear glaze. However, now I am using 6% to 8% for some wall tiles, and woul=
d
love to use the glaze for dishes with food. (Very pretty in a clear glaze
with 4% copper carb) Of course I'd have it tested.... but what about
repeated exposures to heat and dishwashers? Lesley Alexander
Birgit Wright on mon 18 jul 11
Hi Lesley=3D3B I had that same question in the spring=3D2C this is what =
I as=3D
ked=3D2C
=3D20
Hello Claybuds=3D3B I have a question about red slip on plates
> and bowls under clear glaze. It is 20 grams red mason stain to 100
> grams dry clay from my white cone six stoneware plus a lot of water=3D2C
> it is lightly washed over a textured area and then wiped off the
> surface and covered with MC6 transparent liner glaze.=3D20
> >
> What=3D2C if any=3D2C are the problems with this if it is covered with
> glaze? How should I test it besides the vinegar and dishwasher test.
=3D20
I got a lead to send a sample to BSC labs=3D2C Brandywine Science Centre=3D=
2C =3D
=3D20
http://www.bsclab.com/ My test came back <0.01> for cadmium leaching=3D2C=
t=3D
hat is effectively zero=3D2C for all intents and purposes=3D2C and the lowe=
st t=3D
hat is tested for=3D2C because in industry they can never say never.
It was pretty cheap for peace of mind=3D2C about $18.00 for each sample an=
d =3D
my shipping expense=3D2C which was about $8.00.
I had also called the mason stain company http://www.masoncolor.com/Home.=
=3D
htm and talked to one of their lab tech guys=3D2C they explained about the=
e=3D
ncapsulated stains=3D2C this is what they say in their FAQ's.
=3D20
Q. What are "encapsulated" pigments? Are they safe to use?
A. Encapsulation is a special=3D2C patented=3D2C manufacturing process desi=
gned=3D
to incorporate certain metallic oxides into the crystals of zirconium oxid=
=3D
e. They are also referred to as "inclusion" pigments. They are safe to use=
=3D
=3D2C and are now widely used in ceramic manufacture around the world. Obvi=
ou=3D
sly=3D2C as with all finely dispersed powders=3D2C care should be taken to =
keep=3D
operations as dust-free as possible.=3D20
He also said that the cone six that I use is a better temperature for the c=
=3D
olour because higher temps. burn out more.
If you go down about 2/3rds. of the first page on my blog their are picture=
=3D
s of the sample I used.
http://birgitspots.blogspot.com/
Good luck and I would be interested to know what you learn as well.
Cheers=3D2C Birgit Wright=3D20
> Date: Sun=3D2C 17 Jul 2011 20:37:44 -0700
> From: lja9999@GMAIL.COM
> Subject: Chemical question=3D2C inclusion stains
> To: Clayart@LSV.CERAMICS.ORG
>=3D20
> Great to get warm tones using cadmium inclusion stains=3D2C but what is t=
he=3D
ir
> record so far? For food=3D2C I've been timid=3D2C only using stains under=
a g=3D
ood
> clear glaze. However=3D2C now I am using 6% to 8% for some wall tiles=3D2=
C an=3D
d would
> love to use the glaze for dishes with food. (Very pretty in a clear glaze
> with 4% copper carb) Of course I'd have it tested.... but what about
> repeated exposures to heat and dishwashers? Lesley Alexander
=3D
Ron Roy on mon 18 jul 11
Hi Lesley,
Make sure the covering glaze is stable and keep in mind - copper
degrades any glaze - 4% is a lot and the glaze will have to be quite
durable.
RR
Quoting Lesley Alexander :
> Great to get warm tones using cadmium inclusion stains, but what is their
> record so far? For food, I've been timid, only using stains under a good
> clear glaze. However, now I am using 6% to 8% for some wall tiles, and wo=
uld
> love to use the glaze for dishes with food. (Very pretty in a clear glaze
> with 4% copper carb) Of course I'd have it tested.... but what about
> repeated exposures to heat and dishwashers? Lesley Alexander
>
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