ASHPOTS@AOL.COM on wed 15 oct 03
OK , i have some slip. Its from my the clay i use. Its Wonder White cone 10
from Highwater.
My question is what should i use to make a white and a dark slip. I was
thinking whiting and also manganese for the dark or red iron oxide.
Mark
Alisa Clausen on thu 16 oct 03
> OK , i have some slip. Its from my the clay i use. Its Wonder White cone
10
> from Highwater.
> My question is what should i use to make a white and a dark slip. I was
> thinking whiting and also manganese for the dark or red iron oxide.
>
Dear Mark,
Usually I use my own clay to make a slip base. It is a white clay. From
there I color it with oxides, so it is a slip with additives. Introducing a
slip in between the clay and glaze can present a host of potential problems
to tackle.
To whiten a slip can be a challenge. I usually add 10-15% Zircopax.
However, this makes the slip more refractory, and you can experience
crazing. You need to test this of course with the clay you are using.
To darken a slip is a much easier assignment.
In %
Black
1.0 Cobalt ox.
4.5 Copper ox.
4.5 RIO
Brown
10 RIO
or
40% red clay
stains also work fine.
regards from Alisa
Vince Pitelka on thu 16 oct 03
> OK , i have some slip. Its from my the clay i use. Its Wonder White cone
10
> from Highwater.
> My question is what should i use to make a white and a dark slip. I was
> thinking whiting and also manganese for the dark or red iron oxide.
Mark -
It is not practical to try to make a slip lighter in color than the clay you
are using. In other words, you cannot use whiting to "lighten" the color of
a darker stoneware clay. Is your "Wonder White" really white? If so, just
add some zircon opacifier (8%) to make it opaque even if it is applied
thinly.
You can add iron oxide to your stoneware claybody to get a dark slip, but if
you want a very dark slip, I would mix up a special base clay just for this
slip - start with any good reliable porcelain recipe, but then reduce the
feldspar content in proportion to the iron addition, in order to prevent
over-fluxing of the slip in reduction firing. This has always worked well
for me. You can get a good dark brown with an addition of 8% iron oxide.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Office - wpitelka@tntech.edu
615/597-6801 x111, FAX 615/597-6803
http://iweb.tntech.edu/wpitelka/
Bruce on mon 23 jan 06
I just found this list (or it found me) and have enjoyed it. I searched
the archives and have read the posts on slips.
I want to use a porcelain clay body and fire Cone 6 and Cone 10 decorated
with colored slip.
First question, can I fire a Cone 10 porcelain at Cone 6?
Second question, if I use slips made from the clay body in use what
colorant would you suggest to fire to Cone 10?
I plan to cover the slips with a amber glaze.
Thank you in advance.
Bruce
Chris Campbell on mon 23 jan 06
Bruce ..
The problems occur when a Cone 6 clay
is fired at Cone 10 ... not vice versa.
You can fire any clay lower than the
designated temperature. Many people
do this for smoke fired or raku pieces
since under fired clays are more porous
and take the colors well.
However, the finished piece is more
fragile than a properly fired, vitrified body.
The piece will not be functionally safe...
might even seap water.
But, if it is only decorative there is no problem.
Mason Stains fire well to Cone 10. Check with
your clay supplier for a list of all the colors that
are suitable for clay slips and start experimenting.
I mix mine in a small blender using my scraps
of leftover clay. Mix them to a yogurt like state
then apply them with a brush, syringe or even a
baggie with a small hole cut in one end!
Have fun
Chris Campbell - in North Carolina - had a flock of
about 20 Guinea Fowl feeding in my yard this morning
... no idea where they came from ... noisy bunch!
Chris Campbell Pottery LLC
9417 Koupela Drive
Raleigh NC 27615-2233
Fine Colored Porcelain since 1989
1-800-652-1008
Fax : 919-676-2062
website: www.ccpottery.com
wholesale : www.wholesalecrafts.com
Gretchen Mottet on tue 24 jan 06
Bruce - mason stains are very predictable and easy to determine desired
color in slips at cone 6, most to cone 10. I wouldn't fire a cone 10 clay to
cone 6 and expect it to be fully vitrified.
Gretchen Mottet
Art Process Studios
Tacoma, WA 98446
_www.artprocessstudio.com_ (http://www.artprocessstudio.com/)
| |
|
