sdpotter@GTE.NET on wed 30 aug 00
Greetings,
I am seeking info regarding kaolin slips, recipes, application, etc.
I've read what I've been able to find, but I would like a little more.
My sources have not listed any recipes, so I thought I would check
with Clay Art.
Thanks,
Steve Dalton
Alisa and Claus Clausen on wed 30 aug 00
Dear Steve,
I work in the cone 6 range. If that is helpful to you, I will send you =
the two receipes I work with now for
both wet and bone dry/bisque ware. When you say kaolin slip, I am =
thinking you mean a receipe with
kaolin, but other ingredients as well? Decorative slips? Mine are =
pretty basic, clay=B4and flux plus colorant.
best regards,
Alisa in Denmark
Craig Martell on wed 30 aug 00
Steve Dalton wanted to know about Kaolin slips!
Hi:
If you are doing high fire, cone 10 and up the most basic recipe is:
Kaolin 50% by weight
potash spar 25%
silica 25%
To this brew you may also want to add some bentonite, veegum t or cer, or
some macaloid. You can also add colorants just as you would to a glaze.
Keep the clay around 50% for most slips and you can use any kaolin you
would like or a mix of kaolin and ball clay, or perhaps a small amount of
red clay for color.
A good start for wood fire flash slips is: Helmer Kaolin 70, Nepheline
syenite 30. Here, you want to keep the Si/Al ratio low for some orange
blush and the Neph is good because it's high in Al and low in Si. You can
also take a shino glaze and up the clay to 40% and higher for use as a wood
fire slip.
If you use Grolleg kaolin in any slips be aware of the viscosity when you
mix. I think that ECC uses a deflocculant when they mine this stuff with
water jets. It mixes up thick and is thin the next day. I mix a day ahead
and add about 1% dry weight of Epsom Salts and this thickens the slip to a
nice brushing consistency.
Any of these slips can be painted, poured, trailed, or sprayed. If you are
doing leather hard pots most raw slips will adhere well and stay on the
piece. If you apply bone dry or bisque, you may have to do some calcining
or adjust the non plastics in the slip to a higher % than the clay to cut
raw shrinkage.
It would be helpful to others that are willing to help you if you would say
what temp and atmosphere you want to use the slips at. They could then
zero in a bit tighter on the target. I'm just guessing that you want the
slips for high fire.
later, Craig Martell in Oregon
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