David Hendley on fri 1 jan 99
The yellow in your glaze probably comes from titanium dioxide,
which will turn creamy-yellow in high proportions. 12% titanium
in a glaze is extremely high, and I'm surprised you don't have
problems with pin-holeing with that much titanium.
The only way I know of to get a true primary yellow at cone 10
reduction is with a yellow inclusion stain. Regular yellow stains
burn out at ^10R, and rutile and iron will give you an earthy
yellow-ish to gold color, not true primary yellow.
These iron-rutile colors also work best in matt-type glazes, which are
not a good choice for dinner ware sets.
The inclusion stain is reliable, but costs about $40 a pound and
you need about 6-12% in a glaze. I haven't used it in a high lithium
glaze like yours, but it seems to work in any base glaze.
The stain is made be Cerdac, and is available from Trinity Ceramic
Supply in Dallas.
The color in the inclusion stain comes from cadmium. It is
advertised as food-safe, but I would sure want to have the glaze
tested for cadmium release before making a dinner set with it.
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
At 09:20 AM 12/30/98 EST, you wrote:
>----------------------------Original message----------------------------
>I am searching for a 100%reliable bright yellow matt glaze to be used in
cone 10
>gas reduction over miller 900 clay(buff stoneware). I do not want to use any
>glaze that has barium or lead, as this is for a dinner ware set. The best
I have
>come up with is the following
>
>Caramel Yellow
>
>PETALITE 46
>Nepheline syenite 36
>Titanium dioxide 12
>Dolomite 9
>EPK 9
>
>but it is to pale. here are my questions?
>
>1. Where does this glaze get its color from? none of the ingredients seem
to be
>colorants.
>
>2. What can I increase to make the glaze a brighter yellow? can this be done?
>
>3. Can I add something else to make it more yellow? R.I.O.
>
>4. Do you have a better glaze to start off with?
>
>help!!!!
>
>Xavier
>
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