Cindy Strnad on tue 6 jun 00
Jenny,
Mixing commercial stains into glazes of all firing ranges does work. Some
glaze components do not always agree with the color development of some
stains, though. It sounds like you're mixing stains into pre-made commercial
glazes. That is going to be a somewhat hit and miss proposition, but you can
certainly give it a shot.
If you're starting from scratch, experiment with adding up to 10 percent
colorant into your glaze tests. On the low end, this can go to as little as
0.25% stain. Ten percent is pretty high, but is needed for some intense
colors such as blacks. Glaze stains fired metallic oxides, and can leach out
into food if the glaze is not stable, just like raw metallic oxides.
Cindy Strnad
earthenv@gwtc.net
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
Paul Lewing on tue 6 jun 00
Jenny Lewis wrote:
>
So I was wondering - if I mix a colour stain into a clear or
> a white glaze will this produce a colour glaze?
Yes. However, it will be hard to quantify. Keep careful notes if you
want to reproduce an effect.
Will it affect the
> firing temperature?
Maybe. It depends on the chemistry of the glaze, the particular stain
you're using, and the concentration.
I go to a community workshop and don't want to
> be the one to cause glaze puddling all over the kiln shelves.
You're more likely to make the glaze more matt, as some stains are very
refractory. Some colorants are fluxes, it's true, but I doubt you'd be
putting in enough to make them run. You may notice differences in the
glossiness or the fit of some glazes, though.
> I use high-fired stoneware, which goes into an electric kiln. Would
> it be better to try this with low-fire earthenware?
Not necessarily. When people tell you that many stains will not work at
high temperature, they fail to take into account that most people who
fire low-fire do oxidation and most people who fire high-fire do
reduction. It's actually the reduction that kills most of the colors,
not the temperature. Very few colors of stains burn out, some
exceptions being antimony yellows and non-encapsulated cadmium, both
very poisonous, by the way.
Happy testing,
Paul Lewing, Seattle
Earl Brunner on tue 6 jun 00
Years ago I remember that cobalt went through the roof cost
wise, for awhile we substituted underglazes that we got at
discount because off their age or due to stock rotation or
something. Anyway they were marked down as clearance items.
As I recall they didn't mess up the glazes much and we got
blue.
YOu should be able to do it, but you might have to mess
around with it.
If you are careful on the tests, shouldn't be much risk.
Jenny Lewis wrote:
>
> Hi all
>
> I've looked through the archives, and rummaged in the books, but
> can't find quite what I'm thinking about. I recently bought some
> underglaze colours in a moment of enthusiasm, thinking I would
> decorate stuff. Tried, didn't like, probably won't do again for a
> while. So I was wondering - if I mix a colour stain into a clear or
> a white glaze will this produce a colour glaze? Will it affect the
> firing temperature? I go to a community workshop and don't want to
> be the one to cause glaze puddling all over the kiln shelves. I will
> test of course, but I wanted to check first to make sure I'm not
> doing something completely daft. I thought I'd stir in about a
> teaspoonful of the colour into a half pint of glaze to begin with.
>
> I use high-fired stoneware, which goes into an electric kiln. Would
> it be better to try this with low-fire earthenware?
>
> I've tried in the past mixing commercial stains into clay, so vaguely
> thought it should work in a glaze. Very vaguely.
>
> Thank you in advance for any thoughts.
>
> Jenny Lewis
> overlooking Regents Park
> early June and it feels like winter
> brrrr
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Jenny Lewis on tue 6 jun 00
Hi all
I've looked through the archives, and rummaged in the books, but
can't find quite what I'm thinking about. I recently bought some
underglaze colours in a moment of enthusiasm, thinking I would
decorate stuff. Tried, didn't like, probably won't do again for a
while. So I was wondering - if I mix a colour stain into a clear or
a white glaze will this produce a colour glaze? Will it affect the
firing temperature? I go to a community workshop and don't want to
be the one to cause glaze puddling all over the kiln shelves. I will
test of course, but I wanted to check first to make sure I'm not
doing something completely daft. I thought I'd stir in about a
teaspoonful of the colour into a half pint of glaze to begin with.
I use high-fired stoneware, which goes into an electric kiln. Would
it be better to try this with low-fire earthenware?
I've tried in the past mixing commercial stains into clay, so vaguely
thought it should work in a glaze. Very vaguely.
Thank you in advance for any thoughts.
Jenny Lewis
overlooking Regents Park
early June and it feels like winter
brrrr
Paul Taylor on wed 7 jun 00
Dear Jenny
They will work.
It does worry me that you are nervous of trying. If you blunge the
stained glaze that's good, grinding is better for a more even look but it
is not necessary. just a sieving will do. The only disadvantage is that it
would not necessarily be the cheapest way of coloring a glaze or conversely
it may be cheaper that depends on how the stain behaves a stain designed for
slips may do a better job in a matt glaze.
I think there is to much paranoia driven by the safety police as long as
you stay away from lead the only real concern. if you insist on using it.
use it only in silicate form with the stains and additives the supplier
recommends.
Any thing else. Do what you like. I expect some worrier some where will
be concerned with leaching of lithium or boron cobalt etc. I am concerned
that their worries, which many potters believe are disproportionate to real
health dangers, are affecting beginners sense of adventure.
And while I think of it one kiln shelf that you have written off.
painted with thick bat wash for crazier experiments, is good for the nerves.
Regards Paul Taylor.
> From: Jenny Lewis
> Organization: London Business School
> Reply-To: Ceramic Arts Discussion List
> Date: Tue, 6 Jun 2000 11:34:32 BST
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: commercial stains in glazes?
>
> Hi all
> I've tried in the past mixing commercial stains into clay, so vaguely
> thought it should work in a glaze. Very vaguely.
>
> Thank you in advance for any thoughts.
>
> Jenny Lewis
> overlooking Regents Park
> early June and it feels like winter
> brrrr
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
Sharon31 on wed 7 jun 00
Hello Jenny!
You can add up to 10% commercial stain to glaze, low and medium ( I don,t
work higher then ^6 so I cannot tell you ). I do it as the last choice, or
to some of the glazes to my students at all ages as they love GLOSS and
COLOR. For yourself, you can use it in combination with an oxide, Red iron
oxide is good, may be some rutile, powder or granular, in order to lose some
of the "GLOSS and COLOR" which is very boring.I give you here a recipe,
from Pottery Making Illustrated,The way I do with a colorant.
For ^5- ^6
Speckles----- Gray
==================
GERSTLEY BORATE..... 20.00 18.78%
NEPHELINE SYENITE... 20.00 18.78%
FRIT 3110........... 15.00 14.08%
BALL CLAY........... 15.00 14.08%
QUARTZ.............. 30.00 28.17%
IRON OXIDE RED...... 1.50 1.41%
TITANIUM DIOXIDE.... 5.00 4.69%
========
For ^6 you can change the NEPHELINE SYENITE To potash Feldspar.It looks
better above glaze with low alumina.
The Gerstly Borate on this amount can easily substitute for a borax frit
through a software.
...Time to go and mix the glaze of the week
Ababi
sharon@shoval.org.il
http://www.israelceramics.org/main.asp?what=gallery.htm
http://www.milkywayceramics.com/cgallery/asharon.htm
----- Original Message -----
From: Jenny Lewis
To:
Sent: Tuesday, June 06, 2000 01:34
Subject: commercial stains in glazes?
> Hi all
>
> I've looked through the archives, and rummaged in the books, but
> can't find quite what I'm thinking about. I recently bought some
> underglaze colours in a moment of enthusiasm, thinking I would
> decorate stuff. Tried, didn't like, probably won't do again for a
> while. So I was wondering - if I mix a colour stain into a clear or
> a white glaze will this produce a colour glaze? Will it affect the
> firing temperature? I go to a community workshop and don't want to
> be the one to cause glaze puddling all over the kiln shelves. I will
> test of course, but I wanted to check first to make sure I'm not
> doing something completely daft. I thought I'd stir in about a
> teaspoonful of the colour into a half pint of glaze to begin with.
>
> I use high-fired stoneware, which goes into an electric kiln. Would
> it be better to try this with low-fire earthenware?
>
> I've tried in the past mixing commercial stains into clay, so vaguely
> thought it should work in a glaze. Very vaguely.
>
> Thank you in advance for any thoughts.
>
> Jenny Lewis
> overlooking Regents Park
> early June and it feels like winter
> brrrr
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
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