Vince Pitelka on thu 14 apr 05
> Yeah! Like Jonathan says - ya gotta beat it with a hammer! If you are
> using a slab roller - quit it! In my opinion slab rollers suck. I've
> never met a slab worth its weight that came from a slab roller. If you
> insist on using a slab roller - say because you mistakenly invested in
> one and you just gotta use it, then get a good hefty ROLLING pin -
> those one piece jobbies won't do - and compress your slab in all
> directions. Sally Campbell taught me that. And get rid of those
> stupid slab thickness sticks, as with anything else, with a little
> practice you can roll an even slab with a ROLLING pin.
Dear Annie -
This is a bit extreme. Don't knock a good slab roller. They are great
pieces of equipment, and I wouldn't try to do my slab work without one if I
had any choice. In the past, I have often had to do without one, and I do
just fine, but a good slab roller properly used is a great time saver.
In the past on Clayart, I have discussed the problems of slab rollers and
unidirectional grain structure. That is a serious issue, and is the reason
for most of the warping problems that occur on rolled slabs. You hit the
problem dead-on above. When people roll slabs in one direction and then
build things from those slabs, they almost always run into problems with
warpage or separation. Imagine building furniture with green lumber, with
the grain pointing in random directions. The piece would yank itself apart
upon drying. Same with unidirectional slabs, except the wares build up
tension in the drying, and then really warp and/or tear themselves apart in
the firing.
So, as you suggest, a solution is to roll the slabs with a slab roller, and
THEN roll them in all directions with a stout ball-bearing rolling pin.
That eliminates the unidirectional grain structure, and the slab shrinks
evenly in all directions. There can still be problems with warpage because
of other drying and handling problems, but the grain structure is the
biggest culprit.
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/
Annie Chrietzberg on thu 14 apr 05
Yeah! Like Jonathan says - ya gotta beat it with a hammer! If you are
using a slab roller - quit it! In my opinion slab rollers suck. I've
never met a slab worth its weight that came from a slab roller. If you
insist on using a slab roller - say because you mistakenly invested in
one and you just gotta use it, then get a good hefty ROLLING pin -
those one piece jobbies won't do - and compress your slab in all
directions. Sally Campbell taught me that. And get rid of those
stupid slab thickness sticks, as with anything else, with a little
practice you can roll an even slab with a ROLLING pin. It's gotta
roll...
Another thing I've discovered is use the least water possible - water
is the culprit of many clay issues, specifically when the water is
trying to leave. If you are serious about your slab work, a regular
throwing body formulation won't do. If you are making your own clay -
use less water. If you are ordering a ton of a specific mixture, order
it 'ram press consistency.' You will have to beat it into a slab with
a mallet, but those slabs are less likely to warp because less water
has to escape. Go to chineseclayart dot com and splurge on the
hardwood model.
So, I've got a little project in mind that I will get to soon, and it's
in pursuit of the Ultimate Compressed Slab - and it involves some
jackassery with my favorite piece of production equipment - the Ram
Press. Soon, very soon, I'm going to start pressing my slabs with an
even 60 tons of pressure. Don't get arsy and whine about how not
everyone has the luxury of a Ram Press just lying around - I know that,
and I'm willing to share. If any Serious Slab Sculptor out there wants
to explore this with me this summer - contact me off list and maybe we
can work out a little time. I will want to see images of work and some
kind of proposal....
On Apr 13, 2005, at 1:24 PM, Conrad Krebs wrote:
> Hello,
>
> Can anyone tell me the best way to use these clay additives - that is,
> in
> what manner and in what amounts - to reduce warping? I am doing slab
> work
> using lowfire white clay with grog (Laguna EM101) and I am having a
> terrible time with warping. I've tried everything I can think of;
> covered
> the piece with plastic,kept it out of drafts, etc. and nothing seems to
> work. I thought I would try these additives next.
>
> Thanks, Conrad
>
> _______________________________________________________________________
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>
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>
Annie Chrietzberg on fri 15 apr 05
Vince,
slab-roller, schlab-moller. I start my slabs by throwing them. But we
have a slab-roller here for your use when you come for your workshop.
I can't promise not to tease you when you use it! But I'm also the
dork who prefers a kick wheel.
We'll see about the Ram-slabs - it's all conjecture right now, but by
the time your workshop at CDG rolls around, we might have changed the
world of slabs forever, which will also, of course, bring world peace.
anti-slab roller forever, but still your #1 fan,
Annie
On Apr 14, 2005, at 9:27 PM, Vince Pitelka wrote:
>> Yeah! Like Jonathan says - ya gotta beat it with a hammer! If you
>> are
>> using a slab roller - quit it! In my opinion slab rollers suck. I've
>> never met a slab worth its weight that came from a slab roller. If
>> you
>> insist on using a slab roller - say because you mistakenly invested in
>> one and you just gotta use it, then get a good hefty ROLLING pin -
>> those one piece jobbies won't do - and compress your slab in all
>> directions. Sally Campbell taught me that. And get rid of those
>> stupid slab thickness sticks, as with anything else, with a little
>> practice you can roll an even slab with a ROLLING pin.
>
> Dear Annie -
> This is a bit extreme. Don't knock a good slab roller. They are great
> pieces of equipment, and I wouldn't try to do my slab work without one
> if I
> had any choice. In the past, I have often had to do without one, and
> I do
> just fine, but a good slab roller properly used is a great time saver.
>
> In the past on Clayart, I have discussed the problems of slab rollers
> and
> unidirectional grain structure. That is a serious issue, and is the
> reason
> for most of the warping problems that occur on rolled slabs. You hit
> the
> problem dead-on above. When people roll slabs in one direction and
> then
> build things from those slabs, they almost always run into problems
> with
> warpage or separation. Imagine building furniture with green lumber,
> with
> the grain pointing in random directions. The piece would yank itself
> apart
> upon drying. Same with unidirectional slabs, except the wares build up
> tension in the drying, and then really warp and/or tear themselves
> apart in
> the firing.
>
> So, as you suggest, a solution is to roll the slabs with a slab
> roller, and
> THEN roll them in all directions with a stout ball-bearing rolling pin.
> That eliminates the unidirectional grain structure, and the slab
> shrinks
> evenly in all directions. There can still be problems with warpage
> because
> of other drying and handling problems, but the grain structure is the
> biggest culprit.
> 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/
>
> _______________________________________________________________________
> _______
> 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.
>
Ama Menec on tue 19 apr 05
Are the Chinese slab beaters people are talking about like the ones I saw 10
years or so ago in Aberystwyth? They were shaped like a long tom, (tall
flower pot, rim tapering to a narrow base, longer in proportion than your
average flower pot, no thicker rim), with a slice cut out of the side giving
a flat edge along the length. Made of solid wood and with a wooden handle
curving out of the centre of the wide end. These were being used by the
Xching potters and they said their clay was not throwable and that's why all
their pots, no matter how spherical, were slabbed, and that their clay was
unique.
I'd like to know if these beaters would work on less extraordinary clays,
and where do you get them? I could get one made up, but it'd be interesting
to know what weight they are, if they work scaled up for larger slabs, what
sort of wood to use? I'm at the casting stage of my large Cycladic
Goddesses, presently 3'8", and these I'm hoping to press mould with one
continuous slab per half, and I don't have a slab roller or the room for
one. I need to be able to produce a slab just about 4'6" by about 2' wide
pretty quickly before it dries out on my wooden work bench. I'm hoping these
beaters would compress the clay well and prevent warping, and be quick to
do. Any thoughts?
Ama Menec, Totnes, Devon, UK
Email: amamenec@lineone.net
Website: www.amamenec.co.uk
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Marek & Pauline Drzazga-Donaldson on thu 21 apr 05
Dear Annie,
got to disagree with you regarding many things you said regarding making =
slabs using a rolling pin. I agree with you vis-a-vis a slab roller - =
because of preference and space usage and not any other reaqson. I use =
guage sticks and a cutting harp, newspaper and WET CLAY! Heaven forfend!
I also "strike" once or twice across the surface (use a good edge of a =
wooden baten and pull - using the sharp edge only - across the surface. =
This tightens the surface making the use of a rolling pin and all that =
movement a thing of the past. Also you get flat slabs no matter what =
size or thickness. Have been using this method for 30 years, and the few =
warpage problems have been through my inept handling at times.
So Annie I suggest you throw away your rolling pin, save time effort and =
space use a Harp and Guage Sticks and Strike your way to warp free =
slabs. I make many, many slabs for all uses and would recommend it to =
anyone over any other method.
Kidding apart we all have our own methods, but I would serriously =
consider using the above method as the defacto way of making slabs.
happy potting from Marek www.no9uk.com www.moley.uk.com
Kate Johnson on fri 22 apr 05
Hi Marek...since much of my handbuilt stuff in fact begins life as slabs,
I'm very interested in your technique. I use a large rolling pin and spacer
sticks on a thick wooden cutting board for stability at present (I was
getting some flexing in my enamel tabletop that was producing uneven slabs),
and I'm still not entirely happy with my results.
> I use guage sticks and a cutting harp, newspaper and WET CLAY! Heaven
> forfend!
By this you mean the long rectangular sticks with grooves cut in them at
regular intervals, and a wire stretched taut between them? I've asked a
woodworking friend to make me similar sticks, but haven't received them yet.
Once you've cut your slab from the clay, how do you get the size you need if
you're going for larger? What I mean is, I buy boxed clay--even if I cut
slabs from the largest dimension, it's not big enough for my platters and
bigger plates, so I'm assuming cutting thicker and either mashing somehow or
joining slabs?
>I also "strike" once or twice across the surface (use a good edge of a
>wooden baten and pull - using the sharp edge only - across the surface.
>This tightens the surface making the use of a rolling pin and all that
>movement a thing of the past.
Still not seeing how you get large enough slabs, but perhaps that's not an
issue with the kinds of things you're making?
Always ready to try a new technique if it improves my finished product!
Best--
Kate Johnson
http://www.cathyjohnson.info/
Art, History, Nature and More at Cathy Johnson's Cafepress--
http://www.cafepress.com/cathy_johnson/
Graphics/Fine Arts Press--
http://www.epsi.net/graphic/
Susan Fox-Hirschmann on fri 22 apr 05
I roll the first time on the slab roller setting it at about 1/2"
thick....then I spray the canvas with water...both sides and re-roll the slab, but in the
opposite direction, resetting the roller to 1/4" thick , or less if it is
porcelain......and that works for me!
This avoids having to use a rolling pin, which in itself sometimes causes
"impressions"
or other variations...just gotta keep those canvases pretty moist to prevent
the clay from drying out.
Best of luck with "rolling your own!"
Susan
Annandale, VA
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