AKitchens on wed 11 oct 00
I've tried the archives to no avail. There was a post several months ago
about using a mixture of glycerin and oxides and/or mason stains and
water to use as an underglaze. The post mentioned that the artist didn't
measure the amounts. Anyone recall who posted tha? Was it Elizabeth or
Cindy??? Please email me on or offline about the proportions and the
effects.
Thanks,
Nan Kitchens
Mindless in Tennessee
Stephani Stephenson on wed 11 oct 00
Nan
RE: you question on using Glycerin and oxides as underglaze.
I have used glycerin mixed with oxides or stains and it semmed to work
fine.I have a small bottle of glycerine and I used it as a last minute
substitute for CMC to improve brushability( not sure that is a real
word), so haven't tested it thoroughly.
Usually I make underglazes with CMC in the following way
mix some powdered CMC into water ( I don't measure this, seems like a
1/8 cup CMC to a pint of water. I measure enough to impart a slightly
noticeable difference in water viscosity. I also add a couple of
pinches of bentonite to help float the frit.The CMC improves
brushability and imparts a more durable scuff resistant coat to the
unfired surface. I'm not sure if the glycerin has the same effect on
coat durability.
I mix the CMC and water with a submersible blender
then add Stain and Frit and blend again. I add frit because I work at
temperatures from cone 06 to cone 01
I often use Frit 3134. it seems to be a good melter with a wide melting
range and has a less harsh , break through gloss than other frits . The
only time I will not use 3134 is when I am working with warm tones in
over glazes. 3134 seems to bring out greenish tones rather than warm
tones. I usually use an iron laden clay so is often a concern.
Try starting with 50/50 frit/stain and go up or down from there. Or do
a simple line blend. Of course it depends what temp you fire to. At
cone 06 the ratio may be more like 70/30 frit /stain. You will get a lot
of information quite quickly this way.
The ratio also varies with the stain or the oxide ,as some are more
refractory than others.
How many grams of frit or stain you add to make a pint or a quart
depends on a number of variables, how strong of a color do you want, how
much opacity/translucency are you after, etc.
if you want additional opacity try adding zircopax or some white
casting slip. Again a line blend will tell you how much is right for
you.
I don't recall the post you refer to, but this question makes me want to
find out more about glycerin . what is it's make up? how is it
different than CMC?
Sincerely
Stephani Stephenson
Leucadia CA
http://home.earthlink.net/~mudmistress/
Jocelyn McAuley on wed 11 oct 00
Hi Nan (and anyone else interested),
Here are some of the emails that have recently mentioned mixing glycerin
with stains or oxides, plus a couple other related emails. Hope these
help!
Enjoy,
Jocelyn
______________
>From Cindy Strnad, Wed, 10 May 2000, re: Stains
Beth,
Yes. You can use the Mason or other stains in all the ways you mentioned.
For coloring glazes, you might add anything from less than one percent up
to
ten percent. That doesn't mean the stains won't leach out of the glaze.
That
depends upon the stain and the glaze.
For painting on pottery or glaze surfaces, it helps to mix the stains with
frit (I use Ferro 3134) or the ever more elusive gerstly borate, using
glycerin to wet the powders in place of water for ease of application.
Whether you're painting under or over a glaze, you'll want a glaze that
stays put, especially if you're decorating a vertical surface. Otherwise,
your brushwork will run down the pot with the glaze flow. Semi-matte or
matte glazes work best, usually.
Cindy Strnad
earthenv@gwtc.net
Earthen Vessels Pottery
___________
>From Paul Lewing, wed, 10 May 2000 re: Stains
Beth Christensen wrote:
>
> ----------------------------Original message----------------------------
> For cone 6 stoneware, can I use stains to paint designs on my pottery?
Yes
Does
> this mean the Mason Stains I see advertised in catalogs?
Yes, although there are other brands of ceramic stains than those made
by Mason. And you can also use the same coloring oxides that you use to
color glazes. They're what Mason stains are made from.
Do I paint them
> directly on greenware or bisque and then glaze over them with clear
glaze?
Yes, you can paint them directly on either greenware or bisque and put a
clear glaze over them. No need for a separate firing to set the stains.
I always preferred to apply them on bisque because I found I was less
likely to smudge them while I was loading and unloading them in the
bisque. You can also apply them on top of a raw unfired glaze, either a
clear glaze (if you're working with white clay) or a white glaze. Or a
colored glaze, for that matter. A lot of strong colored glazes can look
good with a stain drawing or wash over them. Of course, you would not
apply them under a dark glaze; they'd be wasted.
> Two firings or one? Or do I mix them with the clear glaze first? Or
white
> glaze?
Many people mix their stains with some clear glaze or with a flux such
as a frit or some Gerstley Borate. Some stains need this and some
don't. Most stains will need it more if they're aplied over a glaze
than if they're under. Try each stain alone first and see if you need a
flux. This will also depend on the thickness, clarity, and composition
of the glaze.
Can I use stains to make colored slips out of the clay body I am
> using?
Yes. For best and most consistent results, dry the clay first (trimming
scraps work best for this), crush it, strain it (80 mesh or so), and
weigh it, then add water to the consistency you like. That way you can
determine what percentage of stain you like best. It usually takes
about 6% stain to make a strong color in a glaze, and more to make a
strong colored clay. It will probably take 10% or so to get a
pronounced color in a slip.
Paul Lewing, Seattle
____________
from Deeclay@aol.com, Fri, 14 Jul 2000, Re: Using Mason stains dry
When I use Mason stains, I usually mix with water and a little clear
glaze.
That way they can melt right in. Just wipe excess off the high points.
Try mixing the colors, they can combine nicely. Even mix with colored
glaze. By adding the glaze you get a slight sheen on the high points.
Nice.
Have fun.
Diane in Miami
--
Jocelyn McAuley ><<'> jocie@worlddomination.net
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