Toni Hall on fri 4 sep 98
I saw a recipe for Warren #3 cone 5 glossy green, on page 30 of Sept. 98,
Clay Times. It refers to "good results over crackle white slip". I did not
know there was a slip that crackled. Is there such a thing, and would anyone
be willing to share that recipe?
Thanks in advance. Toni
Donn Buchfinck on sat 5 sep 98
This is the slip recipe that I used through undergrad and grad school. It is
Jeff Oestriecks recipe "I know I can't spell his name right"
he has said that it is a leather hard slip recipe from Rhodes book and that he
tried it on bisque and it worked great.
when you mix it, mix the borax in hot water in a blender to dissolve it or you
will have clumps.
and the last little trick is not to mix anymore than what you plan to use for
the day, the slip stops cracking after awhile, it still works as a bisque
slip but won't crackle.
the calcined kaolin can be picked up at the clay supply store under the name
glomax or some approximation of that, if you are going to make your own
calcined kaolin, take the kiln that it is in up to cone 1.
This recipe has a hard time sticking to porcelain, and for me it peals up and
makes real ugly.
so just use it for stoneware
you can dip it thick, Joseph Bennion uses a slip like this quite thick and it
is really nice. Or thin.
let it dry a little and dip your favorite glaze over it. shino works well,
amber celedon, even 1,2,3,4, celedon works great.
I like to use different kaolins in the recipie, if you calcine grolleg kaolin
and use grolleg in the recipie then use grolleg in the celedon recipie then
you get a great chun like blue over crackle slip.
as a good experiment to try, try making your favorite celedon recipie with
tile 6 as the kaolin, then make the same glaze with grolleg china clay, the
results will be quite different and fun
good luck and keep on potting
White Crackle slip
Borax 5%
zircopax 5%
custer 20%
ball 15%
calcined kaolin 20%
kaolin 15%
flint 20%
P.S. has anyone ever told someone that they are a potter, and you can see it
in their eyes, "is that a legal"
millie carpenter on wed 9 sep 98
Donn or anyone who knows
what is the purpose of having calcined and uncalcined Kaolin in the same
recipe?
Millie in Md, where it is fall
>
> ----------------------------Original message----------------------------
> This is the slip recipe that I used through undergrad and grad school. It is
> Jeff Oestriecks recipe "I know I can't spell his name right"
> he has said that it is a leather hard slip recipe from Rhodes book and that he
> tried it on bisque and it worked great.
> when you mix it, mix the borax in hot water in a blender to dissolve it or you
> will have clumps.
>
> White Crackle slip
>
> Borax 5%
> zircopax 5%
> custer 20%
> ball 15%
> calcined kaolin 20%
> kaolin 15%
> flint 20%
>
douglas gray on fri 11 sep 98
The calcining process removes some if not all of the chemically combined water
and in simple terms allows the Kaolin to begin its process of shrinkage.
The slip needs to shrink enough to form the crackle pattern, but not so much to
make it peel off the surface of the pot. By having both calcined and uncalcined
kaolin in the same batch you are attempting to controll the amount of shrinkage
that occurs in the slip. So you add the uncalcined kaolin to aid in the
shrinkage and the calcined to controll the shrinkage so that it doesn't crackle
too much.
The exact ratio will be determined by the other ingrediants in the recipe and of
course by the clay body the slip is applied to. The key is to find a good match
so that the slip fits almost but not quite like a glove.
In message millie carpenter writes:
> ----------------------------Original message----------------------------
> Donn or anyone who knows
>
> what is the purpose of having calcined and uncalcined Kaolin in the same
> recipe?
>
> Millie in Md, where it is fall
> >
> > ----------------------------Original message----------------------------
> > This is the slip recipe that I used through undergrad and grad school. It
> > is
> > Jeff Oestriecks recipe "I know I can't spell his name right"
> > he has said that it is a leather hard slip recipe from Rhodes book and that
> > he
> > tried it on bisque and it worked great.
> > when you mix it, mix the borax in hot water in a blender to dissolve it or
> > you
> > will have clumps.
> >
> > White Crackle slip
> >
> > Borax 5%
> > zircopax 5%
> > custer 20%
> > ball 15%
> > calcined kaolin 20%
> > kaolin 15%
> > flint 20%
============================================================================ =)
Douglas E. Gray, Assistant Professor of Art
P.O. Box 100547
Department of Fine Arts and Mass Communication
Francis Marion University
Florence, South Carolina 29501-0547
dgray@fmarion.edu
843/661-1535
Tony Hansen on sun 13 sep 98
douglas gray
>make it peel off the surface of the pot. By having both calcined and uncalcine
>kaolin in the same batch you are attempting to controll the amount of shrinkage
>that occurs in the slip. So you add the uncalcined kaolin to aid in the
>shrinkage and the calcined to controll the shrinkage so that it doesn't crackle
>too much.
This suggestion really hits the nail on the head.
Slip recipes need to be tuned to each clay body so they match both the
fired and drying shrinkage. Slips are stuck-on with a glassy bond like
glazes are, we owe it to our customers to minimize the chances of them
flaking off. I see a slip recipe as a mix of calcined/raw clays, frit
and some silica. Tune the frit to maximize maturity to get a good fired
bond with the body, tune the mix of clays to get a good match in drying
shrinkage, tune the flint to get a good match in fired shrinkage.
--
T o n y H a n s e n thansen@digitalfire.com
Don't fight the dragon alone http://digitalfire.com
Calculation/Database Software for Ceramic Industry
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