beth on tue 24 aug 04
I was hoping that you expert slab rollers out there might share your slab
rolling technique with me. I have a Northstar 24-incher, and I've sorta
been on my own in figuring out the best way to use it. (If anyone can
point me to books or videos with slab-rolling instructions, please point
me there!) I keep looking for classes, but they always seem dedicated to
pots and wheel stuff.
Anyhoo...I've figured out a lot for a person who's never actually seen a
slab roller in use, and I can make a decent, yet smallish, slab. But I
hardly think that I'm efficient at it yet. I'd like to be able to make
bigger slabs more consistently and quickly.
Can anyone help? Spare no detail - some little thing you tell me might
click as something I'm not figuring out.
Thanks!!! :)
beth
Madrona Artist on wed 25 aug 04
Hi Beth,
I have used the North Star slab roller for a long time
and this is how I do it.
Align the two canvas sheets together and run 2-3" of
it through the rollers. Then flip the upper canvas
sheet over the top wheel. Now you need to place the
clay on the canvas laying on the table. Two methods
have worked for me for this. (I usually make my slabs
3/8"
You can slice the clay from the bag 3/4" and lay it on
the canvas. If putting more than one slice make sure
you smudge ur peices together by pounding it well. Lay
the canvas voer the roller on the clay and roll. This
method works well with fewer air bubbles. I have
realized though that this usually doesn't give me a
good square slab. Which leads to a lot of unused well
rolled slab when I am making squre tiles.
The second method I use more often for tiles. Cut out
clay from the bag in the form of a log and squish it
to form a log 10" long and 3/4" round. Just squeeze
with your hands till it is approximately that size. I
lay this thick coil parallel to the roller. repeat
again and now place it over laping the previous and
pound along the join with a fist. Continue for another
3-4 logs. Rolling this gives me a good square slab. It
does introduce some air bubbles at times. But after I
rolled it on one side, i squish the bubbles out and
added more clay to those areas and pass it for another
roll.
When rolling clay, move your wheel and tug slightly on
the canvas till the clay gets caught in the rollers.
I hope this helps.
Charan
=====
Madrona Artists Guild
3612 Center Street
Tacoma, WA 98409
http://www.madronaartistsguild.com
madronaartistsguild@yahoo.com
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Vince Pitelka on wed 25 aug 04
> Anyhoo...I've figured out a lot for a person who's never actually seen a
> slab roller in use, and I can make a decent, yet smallish, slab. But I
> hardly think that I'm efficient at it yet. I'd like to be able to make
> bigger slabs more consistently and quickly.
Beth -
The main thing is to remember that the slab roller primarily stretches the
clay in the direction of the rolling, rather than crosswise, so you need to
start with a flat pad of clay that is almost as wide as the slab you want.
Also, if you start with a pad of clay that is already slapped or beaten out
into a rectangle, then the slab roller will have an easy time expanding and
thinning it to the size and thickness you want.
You must always crossroll the slab. That means you need to either roll it
through one way, reduce the thickness setting, and then roll it through at
90 degrees to the first direction, or else you need to roll the slab, and
then crossroll it with a rolling pin. Otherwise you get a unidirectional
grain structure and corresponding extreme drying and firing shrinkage across
the grain, which can cause very serious problems. Personally, I like to use
the slab roller to roll my slabs to slightly thicker than the desired finish
size, and then cross roll them with a large rolling pin - that will
eliminate the unidirectional grain structure, and I can also get the slabs
as thin as I want.
Remember that after you roll the slab once, you will get better performance
from your slab roller if you separate the slab from the canvas before you
roll it again. Just peel off the top canvas, grasp both sheets of canvas at
the far side, lift and flip the slab, and then peel off the other canvas.
Then you can feed the slab through again, and it will expand easily.
For almost any slab roller, it is asking a lot to expect it to tackle a big
thick lump of clay. You are doing the slab roller a big favor if you beat
or slap the clay into a flat pad before you run it through the slab roller.
As mentioned above, the shape of the pad of clay will largely determine the
shape of the slab you end up with. It is hard on your wrists to slap or
beat the clay out with your fists or palms. You can form the pad of clay by
slapping it down on a heavy table or a clean spot on the floor. Also, the
Chinese make a large, broad "mallet" specifically for this purpose, and you
can purchase one from chineseclyayart.com and other sites. As another
option, those rolling pins with the fixed handles - the ones that are turned
out of a single piece of hardwood - they make poor rolling pins, but they
are great for beating lumps of clay to flatten them. The best approach is
to skin the bag off a full bag of clay, and cut it in half lengthwise, and
then beat one of those chunks out so that it is a large, flat rectangle
about an inch and a half thick. Taper it down thinner on one edge, and feed
that edge into the slab roller first.
Good luck -
- 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/
Mayssan Shora Farra on wed 25 aug 04
Hello Beth:
I make a lot of slab work, no formal training but, with a lot of help from
clayarters I seem to have very good luck with them.
I have the North star 24 inch too. I always like to start the slab at the 2
inch mark then turn a 90 degree and upside down at the 1" mark, then go to
the thickness I wnat my slab to be after again rotating and flipping.
If I don't want the texture I would go over the slab now with a wall paper
smoother (18" is what I use) like a rib, after it is all smooth I will add
whatever texture I want on the bottom of the pot including my signature.
Next I lay a smooth newsprint over it and then a masonite bat wider than
the slab and flip the whle thing together( bat,paper,clayslab,and the
canvas) thus I never get stretches in the slab.
I remove the canvas carfully, and if I want the top to be smooth I now will
rib with the wallpaper smoother and if I want any texture or want to press
anything like leaves or lace or rollers or stamps, this is the time I do
that.
If this is not going to be flat, then I will put it in a slump mold now
paper in place as you can remove that after it is leather hard.
I do let everything dry slowly, I will let it dry in the mold till leather
hard ( my favorite molds are shaped newspapers), I use a mini greenhouse to
dry the slabls because the shelves are wire so the slabs dry slowly from
all side at the same rate.
When I take the leather hard from the mold I would remove the paper and
smoothe any roughness, then return it to the green house until totally bone
dry.
I hope this helps, and feel free to ask if you need anymore specifics.
You can also see the results by going to my website:
http://www.clayvillepottery.com
All the Claybeings, the chip and dip sets and most the vases are made this
way.
Mayssan,
in finally getting some summer weather Charleston, WV, USA
Jo Smith on thu 26 aug 04
I use a Large Rubber Mallet that I stole out of my husbands'shop. You can
find them at hardware stores....Jo
>
> It is hard on your wrists to slap or
> beat the clay out with your fists or palms. You can form the pad of clay
by
> slapping it down on a heavy table or a clean spot on the floor. Also, the
> Chinese make a large, broad "mallet" specifically for this purpose, and
you
> can purchase one from chineseclyayart.com and other sites. As another
> option, those rolling pins with the fixed handles - the ones that are
turned
> out of a single piece of hardwood - they make poor rolling pins, but they
> are great for beating lumps of clay to flatten them. The best approach is
> to skin the bag off a full bag of clay, and cut it in half lengthwise, and
> then beat one of those chunks out so that it is a large, flat rectangle
> about an inch and a half thick. Taper it down thinner on one edge, and
feed
> that edge into the slab roller first.
> Good luck -
> - 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/
>
>
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Snail Scott on thu 26 aug 04
At 10:54 PM 8/24/2004 -0400, you wrote:
>...I've figured out a lot for a person who's never actually seen a
>slab roller in use, and I can make a decent, yet smallish, slab. But I
>hardly think that I'm efficient at it yet. I'd like to be able to make
>bigger slabs more consistently and quickly...
One common practice among beginners is to
start with a lump of clay and try to roll
it to its final dimension in one go. Instead,
use multiple passes to take it down in
increments. Some rollers are more forgiving
of doing it all in one pass, but multiple
passes will give you more control anyway,
since you can turn the clay and roll in the
other orientation to give a more even result.
You can also put your clay down as overlapping
pancakes about twice the thickness of your
intended slab. This will give you a shape
close to what you need, instead of the 'penny-
on-a-railroad-track' shape you get from
just running a big lump through. If you use
commercial clay or pugged clay, just slice
the pugs with a harp cutter and lay the
slices out on the roller as you go. If you
need a square result, start with a roughly
square layout.
-Snail Scott
Millard Balfrey on fri 27 aug 04
I hope this may help you avoid mistakes that I have made. I use my Northstar
Super 30 in hand building bonsai pots in plaster forms and for making bottoms
for extruded pieces. #1- purchase three sets of canvas, one for light colored
clay, a second for dark colored clay, and a third for black colored clay. (A
fourth for porcelain) Mark each on both sides with a bold black permenent
marker. I like to cut the clay off the block into thicknesses about twice the
finished thickness using 3/4" x 20" square wood guides. Varnish or polyeurthane
to seal the surface. This helps to avoid cross contaminating colored clay
bodies. For large slabs, overlap the clay about an inch, then I use a $1 thrift
store commercial meat tenderizer to even out the overlaps. I prefer to go slow-
run the slab thru the rollers once each way before adjusting the thumb screw
about 1/8"- flip the slab and remove the canvas to check for voids. Rotate the
canvas 90 degrees, flip again and rotate the canvas to cross roll. When the
slab gets close to finished thickness you can pop bubbles with a fetting knife. I
extruded some 8" round and octoganal cylinders recently, got called away-
covered them with plastic sheeting then slabbed the bottoms the next day. All six
pots cracked in drying due to uneven moisture content. A lesson remembered!
Good Luck- Millard
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