Simon on wed 16 may 01
I'm 'battling' with Naked Raku techniques , also known as Resist Slip.
=20
Has anyone had any luck with Hutchinson's Slip?
I've fiddled and messed about with the alumina content until i got the =
closest i could....
Fireclay 54%
China Clay 34%
Alumina Hydrate 12%
Any less Alumina and the slip fuses to my pots, any more and it falls =
off before it gets out of the raku kiln.
But even now, sometimes my slip just falls off during firing or for no =
apparent reason at all, fuses solidly to the pots and refuses to come =
off at all!!
I'm concentrating focus now, on the water content of the slip, on the =
basis that too much water will result in a thin slip that will not =
craze- and too little will give a thick slip which would crack and fall =
off to easily.
... So, any shared experiences with this one, or any similar i'd be glad =
to hear of !!
Obviously i will post results after this weekend's trials if anyone's =
interested.
Marcia Selsor on thu 17 may 01
Please keep us posted. I have done some "naked raku" and hope to do more
sometime. I had the same type of problems you describe. Too busy to go
in that direction right now. But it is an intriquing technique.
Good luck.
Marcia in Montana
Simon wrote:
>
> I'm 'battling' with Naked Raku techniques , also known as Resist Slip.
>
> Has anyone had any luck with Hutchinson's Slip?
> I've fiddled and messed about with the alumina content until i got the closest i could....
>
> Fireclay 54%
> China Clay 34%
> Alumina Hydrate 12%
>
> Any less Alumina and the slip fuses to my pots, any more and it falls off before it gets out of the raku kiln.
>
> But even now, sometimes my slip just falls off during firing or for no apparent reason at all, fuses solidly to the pots and refuses to come off at all!!
> I'm concentrating focus now, on the water content of the slip, on the basis that too much water will result in a thin slip that will not craze- and too little will give a thick slip which would crack and fall off to easily.
> ... So, any shared experiences with this one, or any similar i'd be glad to hear of !!
> Obviously i will post results after this weekend's trials if anyone's interested.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/Tuscany2001.html
http://www.imt.net/~mjbmls/Gallery.html
craig clark on thu 17 may 01
Simon, I've never used Hutchinson's slip but I do and have done "naked
raku" and occassionally have a problem that is similar to yours. At times
the slip will inexplicably peel off the pot before I put it into the kiln.
This is infrequent and primarily happens on pieces that I have burnished or
that are flat.
One thing that has worked for me is to change the thickness of the slip
a bit. If it is thinner and applied in several coats it doesn't crack as
much, nor does it have a tendencey to pull away as much.
The slip that I use is the slurry from my splash pan and recycle barrel.
It believe it works well because of this. I don't need to adjust for
shrinkage.
Another thing that may pertain to the alumina problem is that the slip
is extremely difficult to remove post firing if the pot is fired to high.
The first coupla times I experimented the pieces were fired to an 06 or so
and it seemed like much of the slip had become fused to the pot. The
solution was to fire to a much lower temperature. I'm talkin not much past
red heat. Just get the pots hot enough to ensure that there is enough
residual heat in them to produce a decent burn. Also, be careful about how
long you let the actual burning occur, if this goes on for much time you may
notice a ghosting type of effect under the overall surface of the slip that
results in a dull grey rather than the high contrast black and white.
As you adjust your resist keep in mind that the peeling is probably due to
excess shrinkage. Snail Scott suggested that I add a bit of calcined kaolin
to the slip inorder to correct for the shrinkage. I believe that he is
correct in his thinking, though I've just relied on thinning my slip a bit
since the problem doesn't occur that much with the slip I'm using.
I have two pots sitting on the shelf that shed the slip. They've just
been sitting there for a few months. I'll try your slip on one of them and
fire lower and apply my slip with a bit of calcined kaolin in it on the
other. Will let you know how things work out.
Craig Dunn Clark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
-----Original Message-----
From: Simon
To: CLAYART@LSV.CERAMICS.ORG
Date: Thursday, May 17, 2001 6:49 AM
Subject: Hutchinson's slip - aka "Naked Raku"
I'm 'battling' with Naked Raku techniques , also known as Resist Slip.
Has anyone had any luck with Hutchinson's Slip?
I've fiddled and messed about with the alumina content until i got the
closest i could....
Fireclay 54%
China Clay 34%
Alumina Hydrate 12%
Any less Alumina and the slip fuses to my pots, any more and it falls off
before it gets out of the raku kiln.
But even now, sometimes my slip just falls off during firing or for no
apparent reason at all, fuses solidly to the pots and refuses to come off at
all!!
I'm concentrating focus now, on the water content of the slip, on the basis
that too much water will result in a thin slip that will not craze- and too
little will give a thick slip which would crack and fall off to easily.
... So, any shared experiences with this one, or any similar i'd be glad to
hear of !!
Obviously i will post results after this weekend's trials if anyone's
interested.
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
kruzewski on fri 18 may 01
Dear Craig,
I sent a long reply to Craig Off list about this but thought I'd sumarise very
quickly on list as this may be of interest.
I was taught a resist slip to use on burnished pots in a smoke firing, either over
masking tape - the smoke burns into the pot from the tape- or scratching a pattern
through it while still wet. The firing was in flaming material and the pot had to
be moved around to catch the flame. If you banged it about enough the slip would
sometimes chip off in the fire.
The ingredients are simple - slip from the wheel and sand in roughly equal parts
daubed on nice and thick.Any sand will do - I used it straight out of the ground,
organic material and all.
If the slip completely covers the pot it will peel like eggshell, if you've
scratched a pattern into it, it needs water and a green scrubber sometimes - but it
does not weld itself to the surface.
I don't know how this would work in the heat of raku kiln, I sometimes got my pots
pretty hot on the fire - hot enough to burn out the carbon if I wasn't careful, and
I'm not sure it would work on an unburnished surface.
Jacqui, North Wales
craig clark wrote:
> Simon, I've never used Hutchinson's slip but I do and have done "naked
> raku" and occassionally have a problem that is similar to yours. At times
> the slip will inexplicably peel off the pot before I put it into the kiln.
> This is infrequent and primarily happens on pieces that I have burnished or
> that are flat.
> One thing that has worked for me is to change the thickness of the slip
> a bit. If it is thinner and applied in several coats it doesn't crack as
> much, nor does it have a tendencey to pull away as much.
> The slip that I use is the slurry from my splash pan and recycle barrel.
> It believe it works well because of this. I don't need to adjust for
> shrinkage.
> Another thing that may pertain to the alumina problem is that the slip
> is extremely difficult to remove post firing if the pot is fired to high.
> The first coupla times I experimented the pieces were fired to an 06 or so
> and it seemed like much of the slip had become fused to the pot. The
> solution was to fire to a much lower temperature. I'm talkin not much past
> red heat. Just get the pots hot enough to ensure that there is enough
> residual heat in them to produce a decent burn. Also, be careful about how
> long you let the actual burning occur, if this goes on for much time you may
> notice a ghosting type of effect under the overall surface of the slip that
> results in a dull grey rather than the high contrast black and white.
> As you adjust your resist keep in mind that the peeling is probably due to
> excess shrinkage. Snail Scott suggested that I add a bit of calcined kaolin
> to the slip inorder to correct for the shrinkage. I believe that he is
> correct in his thinking, though I've just relied on thinning my slip a bit
> since the problem doesn't occur that much with the slip I'm using.
> I have two pots sitting on the shelf that shed the slip. They've just
> been sitting there for a few months. I'll try your slip on one of them and
> fire lower and apply my slip with a bit of calcined kaolin in it on the
> other. Will let you know how things work out.
> Craig Dunn Clark
> 619 East 11 1/2 st
> Houston, Texas 77008
> (713)861-2083
> mudman@hal-pc.org
>
> -----Original Message-----
> From: Simon
> To: CLAYART@LSV.CERAMICS.ORG
> Date: Thursday, May 17, 2001 6:49 AM
> Subject: Hutchinson's slip - aka "Naked Raku"
>
> I'm 'battling' with Naked Raku techniques , also known as Resist Slip.
>
> Has anyone had any luck with Hutchinson's Slip?
> I've fiddled and messed about with the alumina content until i got the
> closest i could....
>
> Fireclay 54%
> China Clay 34%
> Alumina Hydrate 12%
>
> Any less Alumina and the slip fuses to my pots, any more and it falls off
> before it gets out of the raku kiln.
>
> But even now, sometimes my slip just falls off during firing or for no
> apparent reason at all, fuses solidly to the pots and refuses to come off at
> all!!
> I'm concentrating focus now, on the water content of the slip, on the basis
> that too much water will result in a thin slip that will not craze- and too
> little will give a thick slip which would crack and fall off to easily.
> ... So, any shared experiences with this one, or any similar i'd be glad to
> hear of !!
> Obviously i will post results after this weekend's trials if anyone's
> interested.
>
> ____________________________________________________________________________
> __
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Charlie and Linda Riggs on sun 20 may 01
We use the Hutchinson slip all the time but you are right, there is a adjustment problem.
I solved this by using two different fire clays.
Not all fire clays are "created" equal. Some are very plastic and will then shrink when fired. Some are not so plastic and shrink less.
Our current formula is:
Cedar Heights Fire Clay (fine and fairly plastic) 25%
Paco Fire Clay (coarse/sandy and not plastic) 25%
EPK 30%
Alumina Hydrate 20%
You might try calcining some of your fire clay to take the shrinkage out of it and then substituting it for 10-50% of the original fire clay.
We also mix the slip resist VERY thick. Almost at the sludge stage. One slow dip deposits a third of an inch thick coat. The thicker the slip the easier it comes off and the greater the contrast, black and white. Also
the higher the burnish on the pot the easier the slip will shell off.
Bailey Ceramics has a great catalogue that lists ingredients and gives descriptions of their properties. They carry four different fire clays and one is North American Fire Clay which is non plastic.
Good luck
Charlie Riggs
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