Pam Cresswell on sun 16 oct 05
My throwing buddy has been making platters, and he wants to do surface
decorations with slip, where you glop on handfuls of slip and manipulate
with fingers and/or ribs. I have heard that casting slip is better for this
than plain slip made from your throwing body. Is this so? Is there
a magic ingredient in the casting slip, like maybe the sodium silicate, that
we could add to our
plain slip to make it crisper? Maybe borax? I seem to remember in the back
of my feeble brain that borax makes slip more fluid with less h2O. How much
would we need? We are working with ^10 stoneware, but I am also interested
in ^6 slips. If there is a good formula to follow, I would happily mix up a
few buckets :-)
Pam in crispy cool Kansas City, where I am recovering this morning from a
record breaking Raku party fundraiser at the clay guild last night. About
200 folks ate, drank, watched the shows, and went home with a couple of pots
Alisa Liskin Clausen on sun 16 oct 05
Dear Pam,
I work at cone 6. A combination of 50% Borax and 50% Zircopax yields a slip
that holds texture by brush or other, during the firing. I fire it to cone
6 and 7. This mixture, called Desert Slip by Stephanie Stevenson, can be
colored by oxides and stains.
You can use it either on green or bisque ware. I especially like the effect
on bisque wear, as scratching through it as I do, leaves interesting
patterns. I sometimes glaze over it, and the texture is still apparent
under the semi transparent or transparent glazes I use. You can see a photo
of how I have used it with oxides at my website www.alisapots.dk in the
glaze test section. It is under the texture glaze section, called oxide
wash. I use the mixture as is and scratch into it. Then I brush over
oxides. The oxides color the scratches. Then I use a wire brush to brush
off the oxides on the higher areas, revealing the white desert wash again.
I have not idea how high it can be fired before it melts smooth.
It is very hearty and needs a really thick application before it falls off.
I think the problem you may have with slips or engobes so thick that they
hold the texture of how you manipulate them, is that they may crack off.
Certainly adding a high amount of a refractory opacifier like Zircopax to an
ordinary clay slip can give you big peeling problems after the firing.
You do not need to mix a bucket of the Desert slip before you test it
thoroughly. Since it is 1:1 parts, you can mix as much as you need while
you are working.
Good luck,
Alisa in Denmark
Pam Cresswell on tue 18 oct 05
Thanks Alisa!
So your slip has no clay at all? Or do you mean you add zircopax and borax
to a clay body?
That would be one very white slip :-)
Pam
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Alisa Liskin
Clausen
Sent: Sunday, October 16, 2005 1:47 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: [CLAYART] slip for surface decorating question(s)
Dear Pam,
I work at cone 6. A combination of 50% Borax and 50% Zircopax yields a slip
that holds texture by brush or other, during the firing. I fire it to cone
6 and 7. This mixture, called Desert Slip by Stephanie Stevenson, can be
colored by oxides and stains.
You can use it either on green or bisque ware. I especially like the effect
on bisque wear, as scratching through it as I do, leaves interesting
patterns. I sometimes glaze over it, and the texture is still apparent
under the semi transparent or transparent glazes I use. You can see a photo
of how I have used it with oxides at my website www.alisapots.dk in the
glaze test section. It is under the texture glaze section, called oxide
wash. I use the mixture as is and scratch into it. Then I brush over
oxides. The oxides color the scratches. Then I use a wire brush to brush
off the oxides on the higher areas, revealing the white desert wash again.
I have not idea how high it can be fired before it melts smooth.
It is very hearty and needs a really thick application before it falls off.
I think the problem you may have with slips or engobes so thick that they
hold the texture of how you manipulate them, is that they may crack off.
Certainly adding a high amount of a refractory opacifier like Zircopax to an
ordinary clay slip can give you big peeling problems after the firing.
You do not need to mix a bucket of the Desert slip before you test it
thoroughly. Since it is 1:1 parts, you can mix as much as you need while
you are working.
Good luck,
Alisa in Denmark
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