Paul Lewing on sun 30 apr 06
on 4/30/06 4:28 PM, John Rodgers at inua@CHARTER.NET wrote:
> For the SG-12 - it made a nice red-brown that I liked better than the
> Mason stain. And it was made from typical shop chemicals. Rio, Chrome
> Ox, Zinc Ox. Question is, how much does one mix, and how does one add
> it to a glaze. The chemicals have their own proportions in the stain -
> totaling 100%. Then it has to be added to water, glaze or slip. So how
> do you figure how much when applying a calculation. For the mason stain
> it was easy because the stain is uniform throughout. Not so with SG-12
> which is made of three different chemicals.
John, I don't see how the SG-12 would be different from the Mason stain.
I'm sure the Mason red-brown stain also has RIO, chrome and zinc in it.
They just don't tell you the proportions. I'm sure that in both cases all 3
oxides are calcined and milled together. Unless the SG-12 is completely
different from any stain I've ever used, and I'm missing something in your
description, you'd use it exactly like a Mason stain.
Paul Lewing, Seattle
John Rodgers on sun 30 apr 06
I am trying to work out a stain for my project and I have found two -
one Mason Stain, and one from Chappell - SG-12.
The Mason Stain I understand. Add it to a glaze as a percentage of the
total glaze dry weight. The Mason stain is ok, but the SG-12 looks better.
I mixed up some Mason Stain in water, and applied with a brush to a
plate. Very flat when fired. Definitely need something to give it some
life. I needed some glaze or something to go with it to give it
something other than that oh-so flat look. I'm open to suggestions as to
what to do with it to improve the appearance.
For the SG-12 - it made a nice red-brown that I liked better than the
Mason stain. And it was made from typical shop chemicals. Rio, Chrome
Ox, Zinc Ox. Question is, how much does one mix, and how does one add
it to a glaze. The chemicals have their own proportions in the stain -
totaling 100%. Then it has to be added to water, glaze or slip. So how
do you figure how much when applying a calculation. For the mason stain
it was easy because the stain is uniform throughout. Not so with SG-12
which is made of three different chemicals.
Any suggestions?
Thanks,
John Rodgers
Chelsea, AL
David Beumee on mon 1 may 06
Dear John,
I've always found stains to be a very colorful way of working because of the concentration of coloring oxides, but I've never used many commercial stains because they are loaded with opacifiers, and I prefer the classic coloring oxides of iron and cobalt, copper and chrome, etc. I can't tell from your post if you're using stains over or under a glaze, but because you got a dry look from the Mason, I'm guessing you're using them as overglaze.
First, to get an even mix of the RIO, Chrome, and Zinc, add the colorants and alkali to a plastic bag and tie off the top, leaving air inside the bag, and mix thoroughly. If you want to be absolutely sure of an even mix, you can also dry screen the mixture.
I've had the best luck adding percentages of a stain to dried and screened clay body trimmings, usually in the range of 18 to 24% stain mixture. It's possible to add 3 - 24% of a colorant or combination of colorants all in one operation if you have a studio blender.
I apply stains fairly thin and watery at the leather hard stage, just after I've trimmed the pots, and because there is some clay content in the stain mixture, it's less likely to rub off after the bisque. Then, after the bisque, and having waxed the foot, I apply a clear or white glaze over, and fire. Depending on the composition of the glaze and application thickness, you can get some very beautiful effects, particularly on porcelain. Using a fairly thin and watery mixture, you can also use stain mixtures as overglaze, and again, its a matter of testing and experience as to the effects that you want, both for the endless variety of stain mixtures and the particular glazes that you like.
David Beumee
Lafayette, CO
-------------- Original message ----------------------
From: John Rodgers
> I am trying to work out a stain for my project and I have found two -
> one Mason Stain, and one from Chappell - SG-12.
>
> The Mason Stain I understand. Add it to a glaze as a percentage of the
> total glaze dry weight. The Mason stain is ok, but the SG-12 looks better.
>
> I mixed up some Mason Stain in water, and applied with a brush to a
> plate. Very flat when fired. Definitely need something to give it some
> life. I needed some glaze or something to go with it to give it
> something other than that oh-so flat look. I'm open to suggestions as to
> what to do with it to improve the appearance.
>
> For the SG-12 - it made a nice red-brown that I liked better than the
> Mason stain. And it was made from typical shop chemicals. Rio, Chrome
> Ox, Zinc Ox. Question is, how much does one mix, and how does one add
> it to a glaze. The chemicals have their own proportions in the stain -
> totaling 100%. Then it has to be added to water, glaze or slip. So how
> do you figure how much when applying a calculation. For the mason stain
> it was easy because the stain is uniform throughout. Not so with SG-12
> which is made of three different chemicals.
>
> Any suggestions?
>
> Thanks,
>
> John Rodgers
> Chelsea, AL
>
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