Celia Littlecreek on sat 31 mar 01
I had a happy accident that I need to duplicate. I stored my white =
crackle glaze in a bucket that was labeled 04 slip from my local ceramic =
supplier. I taught a workshop and left my glazes to be used by the =
students. Someone (unbeknownced to me) thought the bucket needed to be =
filled and (I think) filled it with slip. I glazed my pot, but strangly =
my glaze did not mature. Disgustedly, I threw it on the shard pile. =
When it landed, the slip chipped off in places and I had my favorite =
pot of the year. I used everything in the bucket and now I need to know =
how to make a slip that "falls away" Mine did not fall away, I think =
because there was white crackle glaze in the bucket. I had to work some =
to get the slip/galze off my pots. I called these pots, egg shell pots, =
because you had to peel them to get the pot out. Any recipes or hints =
for a "fall away slip"? My guess is that it has to mature at a higher =
temperature than the ware it is applied on. All help gladly accepted.
Lewis J Crittenden on sat 31 mar 01
I have applied slip to bisque fired pot and then done a raku firing. The
slip cracked in the raku firing and smoke entered at the cracks and
became very dark at the cracked area then went to light gray where there
were no cracks. After firing, the slip shell easily came off the pot. The
slip would not bond to a bisque fired pot. It is not too often one tries
to have slip not bond, but it can make for some interesting results.
Helen Bates on mon 2 apr 01
This is a technique used to beautiful effect by the Canadian potter
Michael Sheba. He does week-long courses in Haliburton, Ontario, in
the summer. I've taken only his introductory course, which does not
get as far as applying such a technique, but he showed us the work,
and described the technique to us briefly. Amazing work. I can't
find any web links to pictures of his work, but there is text about
him at the Haliburton site:
http://www.flemingc.on.ca/noindex/cf/calendar/PTS/Biography.cfm?InstructorCode=M%2E%20Sheba
Helen
> Date: Sat, 31 Mar 2001 22:14:12 -0600
> From: Lewis J Crittenden
> Subject: Fall Away Slip
>
> I have applied slip to bisque fired pot and then done a raku firing. The
> slip cracked in the raku firing and smoke entered at the cracks and
> became very dark at the cracked area then went to light gray where there
> were no cracks. After firing, the slip shell easily came off the pot. The
> slip would not bond to a bisque fired pot. It is not too often one tries
> to have slip not bond, but it can make for some interesting results.
--
===========================
Helen Bates
mailto:nell@quintenet.com
===========================
Lynne Berman on mon 2 apr 01
Here are some recipes for resist slips, most are used under a glaze in raku.
Many have been gathered from others on Clayart.
Lynne Berman in downtown Philadelphia
NAKED RAKU
Resist Slips and Glazes To Go With Them
David Roberts resist slip
(EPK)Kaolin 3 parts by volume
Flint 2 parts by volume
Copper Oxide 10% (or none)
use with the following glaze
Raku Crackle Glaze
(by David Roberts in Sawdust Firing)
High Alkali Frit 45%
Soft Borax Frit 45%
China Clay 10%
Fire to 1562-1652F.
Glaze Marie-Claire in the Netherlands
90% Borax frit
10% kaolin
____________________________________________________
Resist Slip Marie-Claire
2 parts kaolin
3 parts flint or silica
works with
Glaze
Frit 3110 65%
Gerstley Borate 35%
don't use this glaze with the Roberts slip
__________________________________________________
Jacobsons' Slip and Glaze
Slip
40% Lincoln 60 fireclay
30% 6-Tile clay
20% Ione 412 Grog
10% Custer feldspar
or this variation used without glaze
Chip n Slip
40% Hawthrone Bone or A-P Fireclay
30% Kaolin
20% Pyrotol (or grog)
10% Custer Feldspar
Glaze
60% Ferro Frit 3110
40% Gerstley Borate
Bisque to Cone 012-010
Fire to cone 014 (1540F.), smoke, water-quench, peel
___________________________________________________________
Gordon Hutchens Slip
used without glaze
Fire Clay 50
EPK 30
Alumina Hydrate 20 (or 10% for easier removal)
Marci Masterson
(From Sharon in Fort Worth)
#1
Fire Clay 40 grams
#6 Tile 30 grams
Custer 10 grams
Grog (28 mesh) 20 grams
#3
Fire Clay 50 grams
EPK 40 grams
Soda Spar 10 grams
(Add 5 - 15% grog)
#4
Fire Clay 50 grams
EPK 35 grams
Nepheline Syenite 15 grams
(add 5% grog - no more)
#5
Fire Clay 45 grams
EPK 35 grams
Flint 10 grams
Nepheline Syenite 10 grams
(add 5% Grog - no more)
Notes:
(can't find #2)
#1. If fire clay is gritty, don't need grog (or need less grog).
Interesting small
design w/o grog. Marcie uses 10% grog. Apply one thinned coat crubbed.
Removes very
easily.
#3. Similar to #1. Marcie uses 10% grog.
#4. Semi straight edge design. Applies 4 even coats. Thinner and smaller
design.
Removed easily.
#5. Fairly straight edge design (almost geometric). Hard to remove. Apply
like #4.
Used w/o grog is good but small.
Additional notes: Every thing with talc "fused". Try other fluxes; try
other clays.
Almost all recipes will work with 25-50% raku claybody w/grog or sand. Mix
slip to a
consistency where it will just "pour" not "plop" off a spoon.
The following is the glaze recipe which is applied over the slip:
70% Ferro Frit 3110
30% Gerstly Borate
Mix "milk" thin and apply thinly.
Bruce Girrell on mon 2 apr 01
I've tried a number of these recipes for resist slip, nearly always with the
same result: I never get to fire the piece because the resist slip shells
off just sitting there drying. I have increased/decreased alumina and
fireclay with very little difference in results.
1) What is the consistency of your resist slip?
2) How thick does it end up being on the pot?
3) This may sound stupid, but - Do you allow the slip to dry completely
before firing?
4) Do you always use the glaze overcoat and at what point is it applied?
What am I missing here?
Bruce "trying to get naked" Girrell
craig clark on mon 2 apr 01
Celia, I've recently had a pretty good run with what I believe you are
calling "fall away slip." In my queries and comments to the thread I've used
the term "refractory slip" for the technique. The result is a high contrast
black and white pot with wonderfully shifting and illusive shades of grey
where the flame has burned through the cracks in the slip.
After trying out a few suggestions I ended up going back to what I had
originally done. I take the slip from one of my buckets, thoroughly mix it
to a cake batter like consitency, and brush it onto the pot. If you don't
want a lot of smoking effect brush on several coats, lthis will lead to a
more clearly defined (high contrast) surface. If you're after what I refer
to as the dampening or ghosting of the surface just put on a single layer.
Play with it and see what you get.
The slip that I use comes from my clay body. The clay body is mixed in a
soldner mixer as follows, 100 lbs Hawthorn Bond, 50 lbs Kenntucky Ball Clay,
50 lbs Gold Art, and grog to taste (mine usually runs about 15%.)
After the slip has dried put the pot into your kiln and fire it as you
would a normal raku firing, to a certain point. The difference is in the
temperature to which you fire. Since there is not any glaze to worry about
you don't need to fire that high. I fire by sight, so all I can really tell
you is to look for a dull orange glow in the kiln atmosphere. Sorry I can't
be more specific.
What I have discovered is that the pots don't have to get all that hot.
Just enough to cause a nice healthy combustion when you place them into
reduction (I use newspapers in a garbage can for this purpose.) Infact, the
higher I fire my pots, the more difficult it is for me to remove the slip.
When you reduce the pots don't let them burn to long. I usually look at
the foot ring or the rim to determine where things are going. It's probably
not much more than 10 seconds or so, depending on the size of the piece.
Once again, this is something you'll have to play with a bit until you get a
feel for it. Keep in mind as you're reducing that there is a trade off. If
you're after high contrast you can't burn very long or you'll end up with
considerable smoking, which while nice, dampens the effect.
Play with the thickness of the slip, the application of the slip
(remembering that you're basically using it as a resist), the temperature to
which you fire (not that high. Considerably less than bisque), and the
length of your burn time. Additionally vary the amount of paper that you put
into your can. You don't need that much.
A problem that I'm having, and am working on, is that the slip has a
tendency to peel away completely from tiles and larger heavier forms. It has
been suggested that my slip isn't plastic enough. I'm really not sure. It
may be something as simple as the increased wall thickness in the larger
pieces wicking too much water to quickly from the slip. I actually have
enough time to work on this over the next several days and will let you know
what the results are. I'm almost clueless about the tile problem. It may
have something to do with the burnishing that I do on some of them. Like I
said, I'll let you know.
The technique that I've described has been around in various forms for
quite some time. There are probably a number of people on the list that have
used the refractory slip technique before I even knew that it existed. I'm
using something that works pretty well for me. I'm sure there are others
that do it quite differently. Good Luck!
If you have any further questions, or comments, drop me a note off the
thread or call me. Craig Dunn Clark
619 East 11 1/2 st
Houston, TX 77008
(713) 861-2083
mudman@hal-pc.org
-----Original Message-----
From: Celia Littlecreek
To: CLAYART@LSV.CERAMICS.ORG
Date: Saturday, March 31, 2001 10:10 PM
Subject: Fall Away Slip
I had a happy accident that I need to duplicate. I stored my white crackle
glaze in a bucket that was labeled 04 slip from my local ceramic supplier.
I taught a workshop and left my glazes to be used by the students. Someone
(unbeknownced to me) thought the bucket needed to be filled and (I think)
filled it with slip. I glazed my pot, but strangly my glaze did not mature.
Disgustedly, I threw it on the shard pile. When it landed, the slip chipped
off in places and I had my favorite pot of the year. I used everything in
the bucket and now I need to know how to make a slip that "falls away" Mine
did not fall away, I think because there was white crackle glaze in the
bucket. I had to work some to get the slip/galze off my pots. I called
these pots, egg shell pots, because you had to peel them to get the pot out.
Any recipes or hints for a "fall away slip"? My guess is that it has to
mature at a higher temperature than the ware it is applied on. All help
gladly accepted.
____________________________________________________________________________
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Lewis Crittenden on mon 2 apr 01
Bruce:
When I have done it, I took the same clay as the body and put a small
amount in a blinder and added water. I made it rather thin and applied it with a
brush on the bisque pot. I did several coated very, very thin. It didn't come
off until after it was fired.
--- Lewis Crittenden
--- theoblue44@earthlink.net
--- EarthLink: It's your Internet.
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