Kate Johnson on thu 23 sep 04
>
> Stretched clay always shrinks more than compressed clay - usually the out
> side part of a slab is stretched and the inside compressed - if you can
> compress the outside clay between rolling it you will help solve the
> problem.
Hi Ron...I haven't had this problem much yet (knock wood), but how should
one compress the outside clay without changing the thickness? I don't have
a slab roller and do all my work with wooden spacers and a straight rolling
pin. I turn the clay 90 degrees so I roll it in both directions, and
usually flip it over once during the process, too. Before I start rolling
at all, I flatten in by hand, pushing and patting it till it's near the
final thickness needed. Is there something else I should be doing?
The only real problem I had with warpage was in making a fairly deep
bowl...may have been too much uneven compression needed to make the slab fit
the depth of the press mold, or I may have removed it too soon/handled it
too much. Anyway, I'd like to avoid the problem in the future, because I'd
like to be able to offer more deep bowls!
Regards,
Kate Johnson
Graphics/Fine Arts
http://www.cathyjohnson.info/
http://www.epsi.net/graphic/
http://www.ebsqart.com/Artists/cmd_1494_profile.htm
Ivor and Olive Lewis on fri 24 sep 04
Dear Kate Johnson,
I learned to roll slabs as you describe (1964 with Bob Mason), between
Thicknessing Sticks on Calico. Turned it through 90=BA between passes
and flipping over after each rotation. For small slabs, up to about
one square foot I only rolled one way but for anything larger I start
the rolling pass from the centre, with a push away and then a pull
towards my body. When I flip the clay I place a spare calico sheet on
the clay then a spare rolling board so the slab never gets bent or
stressed in any way.
I believe this process stretches and thins Clay Flocs, inducing a fine
grained interleaved laminate structure which is almost stress free. So
any distortion due to stress relief may be accountable to stress
induced while you are manipulating your clay in the mould.
Hope you solve this one.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
----- Original Message -----
From: "Kate Johnson"
To:
Sent: Friday, 24 September 2004 12:17
Subject: Re: warping slabs
> >
> > Stretched clay always shrinks more than compressed clay - usually
the out
> > side part of a slab is stretched and the inside compressed - if
you can
> > compress the outside clay between rolling it you will help solve
the
> > problem.
>
> Hi Ron...I haven't had this problem much yet (knock wood), but how
should
> one compress the outside clay without changing the thickness? I
don't have
> a slab roller and do all my work with wooden spacers and a straight
rolling
> pin. I turn the clay 90 degrees so I roll it in both directions,
and
> usually flip it over once during the process, too. Before I start
rolling
> at all, I flatten in by hand, pushing and patting it till it's near
the
> final thickness needed. Is there something else I should be doing?
>
> The only real problem I had with warpage was in making a fairly deep
> bowl...may have been too much uneven compression needed to make the
slab fit
> the depth of the press mold, or I may have removed it too
soon/handled it
> too much. Anyway, I'd like to avoid the problem in the future,
because I'd
> like to be able to offer more deep bowls!
>
> Regards,
> Kate Johnson
> Graphics/Fine Arts
> http://www.cathyjohnson.info/
> http://www.epsi.net/graphic/
> http://www.ebsqart.com/Artists/cmd_1494_profile.htm
>
>
______________________________________________________________________
________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your
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> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Mike Martino on fri 24 sep 04
I don't think I've seen this mentioned yet (though I haven't followed the
thread from the beginning), but I paddle my slabs, in to out, out to in, all
four directions. I make sure they are compressed. They never warp. I also
use a rather open clay, and I'm sure this doesn't hurt.
I've heard the guys up around the Seto area (who use fine, plastic clays)
paddle their slabs as well, after wrapping the slab in cloth or mesh. That
way the clay doesn't just spread out, but moves back in when it reaches the
limits of the wrapping. I personally have never done this but my sources are
good.
Another way to create slabs is to coil build a large (usually 15 - 25inches)
cylinder, paddle it from top to bottom to compress the wall, then slice
vertically into as many slabs as I need. This also gives a nice pattern to
the slab depending on the paddle(s) used. Of course, if you don't want a
pattern just scrape it off later.
Cheers,
Mike
in Taku
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Kate Johnson
Sent: Thursday, September 23, 2004 11:48 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: warping slabs
>
> Stretched clay always shrinks more than compressed clay - usually the out
> side part of a slab is stretched and the inside compressed - if you can
> compress the outside clay between rolling it you will help solve the
> problem.
Hi Ron...I haven't had this problem much yet (knock wood), but how should
one compress the outside clay without changing the thickness? I don't have
a slab roller and do all my work with wooden spacers and a straight rolling
pin. I turn the clay 90 degrees so I roll it in both directions, and
usually flip it over once during the process, too. Before I start rolling
at all, I flatten in by hand, pushing and patting it till it's near the
final thickness needed. Is there something else I should be doing?
The only real problem I had with warpage was in making a fairly deep
bowl...may have been too much uneven compression needed to make the slab fit
the depth of the press mold, or I may have removed it too soon/handled it
too much. Anyway, I'd like to avoid the problem in the future, because I'd
like to be able to offer more deep bowls!
Regards,
Kate Johnson
Graphics/Fine Arts
http://www.cathyjohnson.info/
http://www.epsi.net/graphic/
http://www.ebsqart.com/Artists/cmd_1494_profile.htm
____________________________________________________________________________
__
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.
Ron Roy on sat 25 sep 04
Hi Kate,
Tricky question to answer - I can be the clay and it can also be the way
you make slabs - or both - or as you say - how you use em.
I don't have a roller - I make my slabs by throwing them onto the table -
which tends to even out the density. I finish them off with a few rolls of
a rolling pin.
What is required is to try and imagine - where is the clay compressed and
where is it stretched.
Using rails on the sides will help keep the stretch out of the sides - if
the clay is forced up against the rails - and you can - as someone else
suggested - paddle the sides and ends to recompress the clay. You can also
draw a tool around the slab to recompress the edges - maybe the inside part
of a piece of split bamboo - which would compress and round at the same
time. Same idea as recompressing the rim of a thrown pot.
If a slab roller is used - recompress the sides and ends of the slabs and
then roll it again.
Just keep in mind - if parts of the slab are stretched and other parts not
- the stretched parts are going to shrink more during drying and firing.
Anything you do to counter the uneven stretching will improve the
situation.
RR
>> Stretched clay always shrinks more than compressed clay - usually the out
>> side part of a slab is stretched and the inside compressed - if you can
>> compress the outside clay between rolling it you will help solve the
>> problem.
>
>Hi Ron...I haven't had this problem much yet (knock wood), but how should
>one compress the outside clay without changing the thickness? I don't have
>a slab roller and do all my work with wooden spacers and a straight rolling
>pin. I turn the clay 90 degrees so I roll it in both directions, and
>usually flip it over once during the process, too. Before I start rolling
>at all, I flatten in by hand, pushing and patting it till it's near the
>final thickness needed. Is there something else I should be doing?
>
>The only real problem I had with warpage was in making a fairly deep
>bowl...may have been too much uneven compression needed to make the slab fit
>the depth of the press mold, or I may have removed it too soon/handled it
>too much. Anyway, I'd like to avoid the problem in the future, because I'd
>like to be able to offer more deep bowls!
>
>Regards,
>Kate Johnson
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Vince Pitelka on sat 25 sep 04
I have been following most of the posts about this thread, including the
"stretched clay versus compressed clay" and I believe that that is far less
of a problem than the linear grain structure created by the slab roller
stretching the original chunk of clay primarily in one direction. I have
been making almost all of my work from slabs for the last twenty years, and
I am pretty sure that I understand the forces involved. A slab roller
widen's the original lump only minimally. Also, the clay generally sticks
to the canvas below and above pretty uniformaly, and I do not believe there
is much difference in compression from the center to the edges. Mostly, the
slab roller lengthens the original chunk of clay, as described in my post on
this subject a few weeks ago. The problem is that the shrinkage is far
greater across the grain than along the grain. I see no reason to compress
the edges and ends of the slab more than the middle, because the slab gets
longer very evenly as the original lump is rolled through the slab roller.
Speaking of which, you can do a lot to equalize the stresses, while also
making things easier for your slab roller, by slapping the lump on a table
or the floor to make a rectangular wedge-shaped mass, with the sharp edge of
the wedge pulled into the slab roller first. The shape of the lump you feed
into the slab roller has a great deal to do with the shape of the slab you
produce.
There seems to be lots of conjecture about variable shrinkage of slabs, but
it is really very simple, as explained above and in my previous post. If
you just cross-roll with a rolling pin to get rid of the linear grain
structure, there will be no problem. In my slab work, I do not ever
experience strange cracking or separation due to uneven shrinkage of slabs.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Rhonda Kale on sat 25 sep 04
Quote-
".......it is really very simple, as explained above and in my previous post. If
you just cross-roll with a rolling pin to get rid of the linear grain
structure, there will be no problem. In my slab work, I do not ever
experience strange cracking or separation due to uneven shrinkage of slabs.
Best wishes -
- Vince"
It suddenly struck me after I read Vince's post that he was describing how to make a really good pie crust-the technique is the same!
Vince-you make pies too? :-)
Rhonda Kale
31.23595 N, 85.40529 W
Potters Council Member
qndivauniv@earthlink.net
Kate Johnson on sun 26 sep 04
Hi Vince...
>I have been following most of the posts about this thread, including the
> "stretched clay versus compressed clay" and I believe that that is far
> less
> of a problem than the linear grain structure created by the slab roller
> stretching the original chunk of clay primarily in one direction.
We were actually talking about two different ways of producing slabs...I
think some of the answers regarding compression were speaking to the fact
that I asked about hand rolling, with a rolling pin and spacer sticks--I
don't have a slab roller,, but I've put your helpful post in my "Answered
Questions" file in case I ever do, thank you!
Best--
Kate
Kate Johnson on sun 26 sep 04
> Hi Kate,
Hi Ron! (Why does this suddenly sound like an AA meeting...not that I'd
know...)
>
> Tricky question to answer - I can be the clay and it can also be the way
> you make slabs - or both - or as you say - how you use em.
>
> I don't have a roller - I make my slabs by throwing them onto the table -
> which tends to even out the density. I finish them off with a few rolls of
> a rolling pin.
How, "throw"? Hard, enough to make them reasonably flat to begin with, do
you wedge them first or just cut from boxed clay (which is what I do)?
>
> What is required is to try and imagine - where is the clay compressed and
> where is it stretched.
>
> Using rails on the sides will help keep the stretch out of the sides - if
> the clay is forced up against the rails - and you can -
Hmmm, never thought of doing that, I just use the spacer sticks (A wondrous
variety of thicknesses that a friend made for me) to rest the rolling pin on
to equalize thickness. (I do find that I STILL manage to get some slabs of
an uneven thickness and cannot for the life of me figure out how!)
as someone else
> suggested - paddle the sides and ends to recompress the clay. You can also
> draw a tool around the slab to recompress the edges - maybe the inside
> part
> of a piece of split bamboo - which would compress and round at the same
> time. Same idea as recompressing the rim of a thrown pot.
Will give this a try, thanks!
> Just keep in mind - if parts of the slab are stretched and other parts not
> - the stretched parts are going to shrink more during drying and firing.
> Anything you do to counter the uneven stretching will improve the
> situation.
I think perhaps the problem lies in what I am trying to do with the slab
after it's made. I haven't had problems with warping in most of the things
I make, but trying to fit a flat slab into a deep, round bowl as a press
mold may just be expecting more than one can expect from a slab. There's a
fair amount of stretching and fitting going on, and although I tried to do
it evenly, I'm guessing that areas that formed themselves to the mold more
quickly got less manipulation. Perhaps this is a place to use the coil
method, instead...
Thanks for your help--
Regards,
Kate Johnson
Graphics/Fine Arts
http://www.cathyjohnson.info/
http://www.epsi.net/graphic/
http://www.ebsqart.com/Artists/cmd_1494_profile.htm
Kate Johnson on sun 26 sep 04
> Another way to create slabs is to coil build a large (usually 15 -
> 25inches)
> cylinder, paddle it from top to bottom to compress the wall, then slice
> vertically into as many slabs as I need. This also gives a nice pattern to
> the slab depending on the paddle(s) used. Of course, if you don't want a
> pattern just scrape it off later.
>
Thank you, Mike, this one goes into my Pottery Answers file as well...sounds
interesting! I am, unfortunately, rather lousy at making coils...MORE
PRACTICE needed...
Regards,
Kate Johnson
Graphics/Fine Arts
http://www.cathyjohnson.info/
http://www.epsi.net/graphic/
http://www.ebsqart.com/Artists/cmd_1494_profile.htm
Kate Johnson on sun 26 sep 04
Good morning, Ivor--catching up on the list here, as you can tell!
> Dear Kate Johnson,
I learned to roll slabs as you describe (1964 with Bob Mason), between
Thicknessing Sticks on Calico. Turned it through 90º between passes
and flipping over after each rotation. For small slabs, up to about
one square foot I only rolled one way but for anything larger I start
the rolling pass from the centre, with a push away and then a pull
towards my body.
Thanks, good sir, will try that too--I think I instinctively do something
similar, but the pull towards the body is not as emphatic as the other...
>When I flip the clay I place a spare calico sheet on
the clay then a spare rolling board so the slab never gets bent or
stressed in any way.
Another excellent tip, thank you...
>I believe this process stretches and thins Clay Flocs, inducing a fine
grained interleaved laminate structure which is almost stress free. So
any distortion due to stress relief may be accountable to stress
induced while you are manipulating your clay in the mould.
Yep, that's what I'm afraid of...I love the deep bowl form, but it isn't a
natural fit with slab building, perhaps...
> Hope you solve this one.
ME TOO, I'd like to make more of these large bowls! I have a commission to
do one, but happily they want it made up of differentiated spiralled coils
(does that make sense?), which is much, much easier, if a bit more
time-consuming...(and since the spirals are small, if I get the coils uneven
I just break them off and use the uniform parts!)
Again, thanks all...
Best--
Kate
J Lutz on sun 26 sep 04
All this discussion about making slabs has me wondering if I've stumbled
onto a great solution or again just doing something really stupid.
When I first encountered a slab roller it was one with boards to adjust the
thickness. I would grab a fist full of clay and lay it on the canvas
covered board and then continue lining up wads of clay to cover about a
foot square. I'd then mush (technical term) it down by pounding with my
fist to smooth off the higher pieces. This would then be compressed by
rolling it through the slab roller. I never turned the clay and didn't take
care not to stretch it or fold it. I knew nothing at the time and the
instructor apparently didn't either. In any event I was making slab plates
and I don't recall ever having much of a warping problem. Maybe it was
beginners luck.
Later when I acquired my own slab roller (a North Star) I began to use it
differently. It was probably because of the difference is construction and
the way it -the North Star is used in that the clay moves instead of the
roller.
I started by cutting off a slab of clay from the bagged clay and laying it
near the roller and rolling it through. This would result in a rectangular
shaped slab with ragged edges. In an attempt to eliminate the ragged edges
I started folding the rectangle and putting that through the roller. That
soon developed into a habit of folding the clay with the fold perpendicular
to the roller then lifting the folded piece of clay and laying it on the
canvas with the fold so it would enter the roller first. (turning it
90deg.) I might do this fold procedure 3 or 4 times on one slab before
getting it the way I want. If I'm careful from that point to not bend the
slab I rarely have significant warping problems.
I started out using grogged clay like Calico and now use only B-Mix - no
grog. Don't know if the different type of clay with the different technique
is significant or not. I didn't know enough in the beginning to keep notes.
In any event, with the discussion of lining up the clay particles etc. I'm
wondering what I'm doing to the clay by layering it so many times and
putting it through the rollers several times in both directions. Thinking
about it is like trying to remember what fold you're on when making puff
pastry.
Jean Lutz
Prescott, AZ
Vince Pitelka on sun 26 sep 04
> I started by cutting off a slab of clay from the bagged clay and laying it
> near the roller and rolling it through. This would result in a rectangular
> shaped slab with ragged edges. In an attempt to eliminate the ragged edges
> I started folding the rectangle and putting that through the roller. That
> soon developed into a habit of folding the clay with the fold
> perpendicular
> to the roller then lifting the folded piece of clay and laying it on the
> canvas with the fold so it would enter the roller first. (turning it
> 90deg.) I might do this fold procedure 3 or 4 times on one slab before
> getting it the way I want. If I'm careful from that point to not bend the
> slab I rarely have significant warping problems.
Jean -
I think you have invented "plyclay' (like plywood). Since you are turning
the slab 90 degrees wiht each pass, you are eliminating any dominant
directional grain structure.
And regarding your earlier experience with the Brent slab roller, you might
have been using a more refractory claybody, less prone to warpage. That is
a major factor in slab work.
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Ron Roy on mon 27 sep 04
Hi Kate,
I always work with wedged clay but if you clay comes in good shape then I
don't see why it would not work right out of the box. Throwing clay tends
to overcome the results of a pug mill.
I knew I would have to answer this but I'm not sure I can - maybe someone
else can jump in here.
Throwing slabs - and I have done it by throwing cylinders and cutting them
open - it works but its not so easy to get em even.
Making slabs by throwing clay on a table is fast, easy and fun. The trick
is - never throw them down - the clay sticks to the table and that is not
what you want.
Start with a thick but flattened piece of clay - round - square - whatever.
Throw it horizontally across the table so the trailing end contacts the
table before the leading edge. The clay stretches each time - a little
practice is all it takes.
If the sound at contact is loud you have a problem - it means you did not
get any stretching - what you want is to be able to lift the slab off the
table easily each time. As you get better at it you can throw the clay
quite hard - reducing a slab from two inches to a half inch is possible in
3 to 4 throws. When you get close to the thickness you want you can simply
throw it easy.
Part of the problem can be getting the clay too thin too fast - you can
make very thin slabs this way very easily by the way - with all kinds of
interesting texture.
You can throw towards you or to one side - in between those two extremes is
probably what you will end up doing - I thrown mine towards my left side.
The trick is to stop just before you get the thiness you want - then finish
with the rolling pin and rails.
You are going to enjoy making slabs this way - as I said - it's fun.
When I am mixing hard and soft clay - I layer hard and soft - then throw
the stack which makes the layers thiner - restack - and throw again. Doing
that about 7 times mixes the clay very well and not much wedging is
necessary to get the clay perfectly mixed.
RR
>How, "throw"? Hard, enough to make them reasonably flat to begin with, do
>you wedge them first or just cut from boxed clay (which is what I do)?
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Url Krueger on mon 27 sep 04
I believe the first mention of this problem was
in relation to using a slab to create a deep bowl.
In doing that wouldn't there be lots of folds or
overlaps unless one cut gussets out of the slab and
rejoined edges.
I don't believe anyone has said anything about the
varying thickness of these folds. Might not this
be the cause of the warping?
--
Earl K...
Bothell WA, USA
"You may be disappointed if you fail,
but you are doomed if you don't try."
Beverly Sills (1929 - )
Vince Pitelka on mon 27 sep 04
Ron -
Sorry if it seemed like I was dismissing yours or anyone else's approach to
dealing with slab warpage. That was not my intention. I was simply trying
to explain a tried and true method that has worked very well for me for
twenty years. When I first started working with slabs I had significant
problems with cracking and warpage, and I tried everything I could think of.
One thing I did was to work on rolling-pin technique that compresses the
slab all over - rolling out from the center, and then rolling along the
edges. By varying the pressure at one end of the rolling pin or the other
when rolling along the edge, I was able to roll the slab to achieve very
even thickness and compression over all, with no taper at the edges.
Here is something else I discovered. If a slab is rolled very many times
while stuck to canvas on one side, it introduces uneven stresses on the two
faces of the slab that can compound warpage problems. I roll with the
rolling pin as described above, and as soon as the slab stops moving, it
indicates that it is well-stuck to the canvas beneath the slab. I smooth
down another piece of canvas over the upper surface, grasp both pieces of
canvas on the far side of the slab, lift it, and flip it over towards me. I
peel off the stuck sheet of canvas, and roll some more, expanding the slab
further, until it is stuck again, and repeat this process as many times as
necessary. When one gets used to this method it is very fast, and the
resulting slabs are pretty reliable.
You are right, Ron, I do not make tiles, and I do not know much about the
problems involved. But the original questions was in reference to slab
plates, and I have made plenty of those. As always, I am just speaking
from my own experience.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/
Kate Johnson on tue 28 sep 04
>I believe the first mention of this problem was
> in relation to using a slab to create a deep bowl.
> In doing that wouldn't there be lots of folds or
> overlaps unless one cut gussets out of the slab and
> rejoined edges.
>
> I don't believe anyone has said anything about the
> varying thickness of these folds. Might not this
> be the cause of the warping?
Hi Earl...I think it was my question, originally, that started the
discussion, and all I can tell you is that I pushed and stretched very
slowly and carefully, trying to keep the walls of the bowl of a uniform
thickness. No folding, no gussets, just more than my normal amount of
patience.
I'm guessing as other have suggested that it was the combination of
stretching some areas and compressing in others that caused the problem...if
I do more deep bowls without a wheel, I'm thinking the slab method is not
the best to try, at least not the way I did it...
And also still wondering if handling it too soon (taking it out of the mold
before it was fully leather hard) didn't make it worse. Clay DOES have a
memory, as Ivor noted, and I impressed it's little flocculated "brain cells"
with being somewhat out of shape. Patting it back INTO shape wasn't
sufficient to make it "forget."
Regards,
Kate Johnson
Graphics/Fine Arts
http://www.cathyjohnson.info/
http://www.epsi.net/graphic/
http://www.ebsqart.com/Artists/cmd_1494_profile.htm
Ron Roy on tue 28 sep 04
Hi Vince,
Yes - thanks for mentioning that - I left that part out. I always lift the
slab between rollings - and stretch it a little as I do.
I also ment to stess the working on wood part - throwing slabs on canvas is
an excellent way to raise the airbourn silica levels in a studio.
I have always worked on plywood - you can work on just about any surface
but it sometimes takes time to figure out how.
RR
>Here is something else I discovered. If a slab is rolled very many times
>while stuck to canvas on one side, it introduces uneven stresses on the two
>faces of the slab that can compound warpage problems. I roll with the
>rolling pin as described above, and as soon as the slab stops moving, it
>indicates that it is well-stuck to the canvas beneath the slab. I smooth
>down another piece of canvas over the upper surface, grasp both pieces of
>canvas on the far side of the slab, lift it, and flip it over towards me. I
>peel off the stuck sheet of canvas, and roll some more, expanding the slab
>further, until it is stuck again, and repeat this process as many times as
>necessary. When one gets used to this method it is very fast, and the
>resulting slabs are pretty reliable.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Marcia Selsor on fri 23 sep 05
I didn't see the original post..only Stephanie's and Lisa's reply.
Both were good responses and as always in clay there are many answers.
One thing I learned from Kurt Weiser over two decades ago... wax the
edges before they dry. I wax the edges with liquid wax from
Aftosa..that green wax. I dilute it a little and wax two inched
around the edge of my larger (24 inch slabs. Then I dry them slowly
on sheet rock..just the bottom is on sheet rock and the whole ware
rack of slabs is wrapped in plastic. Since it is paper clay it takes
a few weeks to dry..even in Montana.
Marcia Selsor
Potters Council Charter Member
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