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mixing one's own "underglazes"

updated thu 4 oct 07

 

Lili Krakowski on tue 2 oct 07


Leigh tells us:


"I'm thinking about trying to make my own underglazes or colored slips (not
sure what the difference is). I have been looking at the Mason Stains
available and I've searched the archives and found some underglaze recipes."


As Snail explained there is not such thing as an "underglaze" only something
sold in little jars and called that.
This use of a name for something it is not can be seen daily on TV--where
people run around in what I, and my generation, call "underwear" but which
now is called outerwear even formal outerwear!

Glaze colorants are different oxides or carbonates (sometimes sulphates)
that in combination with a glaze of a particular composition will achieve a
certain color. Many colorants will react or interact with the materials in
the glaze and give a diversity of hues. Oxidation or reduction firing also
affects final color.

These colorants cannot be mixed together like paints!

So what are these stains and underglazes?

They are prepared mixes of these colorant oxides, made up very carefully
under lab conditions. As the individual potter rarely has the facilities
for testing and fine tuning, she is better off to buy a stain or underglaze
for the hard to get shades. They can be applied under a transparent or semi
transparent glaze, mixed into a glaze, painted atop the unfired glaze. They
can be put into slips, or engobes....

They are--because the ingredients are--quite costly. And I certainly would
urge you to read some books and gain an understanding of what the different
colorants are capable of. I also would urge you to limit yourself to one of
two colorants to begin with and practice your decoration with them till you
have a feeling for the whole thing. (Of course if you are a skilled painter
or calligrapher, apologies....)

As to the difference between slips and underglazes. As a rule what is sold
as underglaze is very concentrated colorant. Slips contain far less. Again
a book will explain.
























Lili Krakowski
Be of good courage

Elizabeth Priddy on tue 2 oct 07


So what are these stains and underglazes?

They are prepared mixes of these colorant oxides, made up very
carefully
under lab conditions. As the individual potter rarely has the
facilities
for testing and fine tuning, she is better off to buy a stain or
underglaze
for the hard to get shades. They can be applied under a transparent or
semi
transparent glaze, mixed into a glaze, painted atop the unfired glaze.
They
can be put into slips, or engobes....
--___________________________________

The underglazes I use respnd badly to glazes with zinc.

So if you are using commercial underglazes UNDER a
clear glaze, be sure it has no zinc, which makes a cloudy
film over your lovely painting.

Other than that caveat, I strongly recommend Amaco
Reward Velvet Underglazes, as the color remains true
through blending and are not that expensive.

I don't know where it comes from that they are expensive.
A small 4 oz jar is about $4, and it would last me a month
and all I do is paint things.

Perhaps that is relative as well. In terms of getting great
color efficiently and without loss due to misapplication due
to inability to see the color as you apply it, it is dirt cheap.

My 2 cents on it. To see my use of velvets look at the galleries
on the website below.


E


Elizabeth Priddy
Beaufort, NC - USA

Natural Instincts Conference Information:
http://downtothepottershouse.com/NaturalInstincts.html
http://www.elizabethpriddy.com
http://www.flickr.com/photos/7973282@N03/

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Jeanie Silver on wed 3 oct 07


It Depends on what you want, and one size definitely does not fit all.
As, with many issues in clay, there is a conceptual continuum along which
you can engage your energies, depending on your nature.
At one end of the continuum is the idea of using materials that are at hand,
or most convienient. If you start with exploring what the materials can do,
you will end up learning a lot about what You can do. I think of this as
the 'love the one you're with' approach....many people have utilized
commercial underglazes like the velvets, in this way. The consistency and
convieniance of these materials have cleared the way for them to wrassle
with the nitty gritty of making. (There's no right or wrong along this
continuum-its just a case of learning what fits your working nature)
But some people have a precise sense of what they seek. I think of this as
the 'if you can't be with the one you love, build a car and go there'
approach. So in a sense, they are working exactly backwards and opposite
from folks at the other end of the continuum. I like thinking about it like
this because it mirrors the craft/art experience in a way that doesn't
denigrate either extreme....I'm more that kind of nature, so this was how I
arrived at the materials I use...
My thinking was like this: I want to control my imagery exactly. But I want
the surface of my pots to be so clayish that it seems the image has floated
to the surface from the central volume of the pot. So it was a no brainer
to realize that I needed to make my images with slip-with clay itself. The
clayish aspect of the image is more important than nuanced or descriptive
color, so I didn't need the consistency and mixability of commercial
underglazes. But a lot of different, good saturated colors was important.
So I work with a slip that I got from the sculptor Judy Moonelis about 25
years ago, and have tinkered with since. It belies conventional wisdom
about slip in that it will work well on wet, leatherhard, grren or(thinned
somewhat) on bisque. To this I add 2-3 Tbl. of Mason stains,mixed well with
a little water and added wet to one cup of wet,creamthick slip. The Mason
stain Co. puts out an excellent chart with all kinds of info keyed to a
code. Learn the code! Then you will have a good tool to make the color you
want, to go under the glaze that you have...
I didn't mean to go on like this,but I hope it will help someone to realize
that you Can be with the one you love-one way or another..
Jeanie in Pennslyvania(whew! long word...)