Stephen Sell on sat 21 dec 96
I have been wedging clay on a canvas covered board for quite a while and am
tiring of kneeling on the floor to do so. I would like to make myself a
wedging / drying table and wanted to solicit suggestions on an effective
design. I have used a plaster wedging table at school that, over the years,
has developed severe cracks but otherwise works well for wedging and drying
excessively wet clay. Is there an optimum depth that the plaster should be
poured? Reinforcing material? Is there other mediums that work well.
Stephen R. Sell
Pittsburgh, PA
"For every lie I unlearn, I learn something new" -- Ani Difranco
Tadeusz Westawic on sun 22 dec 96
Stephen Sell wrote:
>
> ----------------------------Original message----------------------------
> I have been wedging clay on a canvas covered board for quite a while and am
> tiring of kneeling on the floor to do so. I would like to make myself a
> wedging / drying table and wanted to solicit suggestions on an effective
> design. I have used a plaster wedging table at school that, over the years,
> has developed severe cracks but otherwise works well for wedging and drying
> excessively wet clay. Is there an optimum depth that the plaster should be
> poured? Reinforcing material? Is there other mediums that work well.
>
> Stephen R. Sell
> Pittsburgh, PA
>
> "For every lie I unlearn, I learn something new" -- Ani Difranco
I found some broken architectural marble slabs (pink). They are about
3/4 inches thick. I've been wedging on them for 3 years now and they are
great! I can clean them with the spackle knife and they don't get scored
or scratched. I've managed to break one of them when slamming a heavy
chunk of clay on it. I think this happened because the marble slab was
not fully supported underneath. It sits on a welded steel table frame
with the marble forming the table top. I'm going to repair it in the
Spring by putting a plaster and sand bed underneath the slab.
There is also the "tilt" thing for wedging tables that is important to
avoid carpal tunnel. I don't know much about it, but I'm sure someone
else will comment.
Tadzu with a frozen studio in SW New Mexico.
Robert Kittel on sun 22 dec 96
At 02:43 PM 12/21/96 +0000, you wrote:
>----------------------------Original message----------------------------
>I have been wedging clay on a canvas covered board for quite a while and am
>tiring of kneeling on the floor to do so. I would like to make myself a
>wedging / drying table and wanted to solicit suggestions on an effective
>design. I have used a plaster wedging table at school that, over the years,
>has developed severe cracks but otherwise works well for wedging and drying
>excessively wet clay. Is there an optimum depth that the plaster should be
>poured? Reinforcing material? Is there other mediums that work well.
>
>Stephen R. Sell
>Pittsburgh, PA
>
>"For every lie I unlearn, I learn something new" -- Ani Difranco
Stephen
Plaster, generally is like concrete and cracks will appear no matter what
you do. This is usually from drying. You can slow down plaster drying by
adding sugar, about a teaspoon for a 5 gallon bucket mixed. I remember the
plaster wedging tables at school, they were about 3 1/2-4" thick and seemed
to work just fine.
Bob
Marcia Selsor & Matt Benacquista on sun 22 dec 96
Stephen Sell wrote:
>
> ----------------------------Original message----------------------------
> I have been wedging clay on a canvas covered board for quite a while and am...
"For every lie I unlearn, I learn something new" -- Ani Difranco
Dear Stephen,
I use Potter's plaster and made several frames for the campus shop
from 4x4"s for weight and sturdiness. I used a 3 1/2" thickness about
18" x 36" > We've been using it for years. Made it so the plaster can be
flipped over after wear depressions get too deep. No cracks yet.
I think some cracks can develop (saw this years ago on our old table)
when students slam clay down on the plaster. Somewhere this slam type of
wedging is being taught(?). I am unfamiliar with the idea behind it.
Make sure you mahke the height right for your body.
Marcia in Montana.
--
Marci Selsor
Matt Benacquista
http://www.imt.net/~mjbmls/
mjbmls@imt.net
Numo Jaeger and Michael Miller on sun 22 dec 96
Hello Stephen,
I would suggest making the the plaster wedging table thickness around 3
inches deep. Get the specks on the different kinds of plaster. You might
want to use a harder plaster so the wedging table lasts longer...if it is a
harder plaster it won't absorb as much water...
There is an interesting version of a wedging table in the book called
"Building Pottery Equipment" by Roger Harvey and Sylvia and John Knob
It is a wedging table that calls for the use of a 25 x 25 piece of 18 to 24
gauge aluminum sheet and a 30 x 30 piece of aluminum insect screening.
Page 160 of the book.
Numo
jaegmil@ccnet.com
At 09:43 AM 12/21/96 EST, you wrote:
>----------------------------Original message----------------------------
>I have been wedging clay on a canvas covered board for quite a while and am
>tiring of kneeling on the floor to do so. I would like to make myself a
>wedging / drying table and wanted to solicit suggestions on an effective
>design. I have used a plaster wedging table at school that, over the years,
>has developed severe cracks but otherwise works well for wedging and drying
>excessively wet clay. Is there an optimum depth that the plaster should be
>poured? Reinforcing material? Is there other mediums that work well.
>
>Stephen R. Sell
>Pittsburgh, PA
>
>"For every lie I unlearn, I learn something new" -- Ani Difranco
>
>
Tom Buck on sun 22 dec 96
Bob: Sometimes it is worthwhile to include in the middle of the plaster
wedging form a layer of chiken wire (say 15 -25 mm mesh). One afixes the
wire tightly to the wooden form for the table such that it will end up in
the middle of the set plaster. The wire helps to prevent cracks in the
form when clay is slammed onto it.
Cheers TomB Hamilton ON Canada URL http://digitalfire.com/magic/tombuck.htm
Carl Ross on sun 22 dec 96
In a message dated 96-12-22 11:01:41 EST, mjbmls@imt.net (Marcia Selsor &
Matt Benacquista) writes:
<< Somewhere this slam type of wedging is being taught(?) >>
Dear Marci,
I've always been tuaght to slam it down a few times while wedging, but only
on the corner of the table where the sturdy leg is. It's to "get the
molecules moving" after its long sitting.
Also, I've recently been told be careful with clay around plaster as plaster
will explode in the firing. How do you protect your wares from getting
plaster in them while preserving the absorbance of the surface? I would think
with a cracked surface would come small fragments of plaster which would
pollute your clay and make it dangerous to fire with other peices. Are there
ways of containing the plaster in the wedging surface so it doesn't get out?
Are there alternatives to plaster that are still quite absorbant?
Confused in Phillips,
Carl
Would a thick bisque slab work or woul the clay
Gavin Stairs on mon 23 dec 96
Concerning wedging tables:
I too am about to construct a wedging table, and I'm grateful for the
discussion. The use of plaster on a wedging plate seems to be more a
question of hallowed usage rather than any form of rational design. The
main properties of plaster that make it useful in clay work are:
castability, slight expansion on curing, porosity and ability to absorb
water, and a moderate amount of strength and durability. Plaster seems to
be irreplacable for forms, moulds and drying slabs. Wedging tables,
especially those used to slam the clay down on, need to be rather more
durable than plaster mormally is. It seems that all plaster wedging tables
break sooner or later.
Is there any need for the wedging surface to be water absorbent? I suspect
not. Rather, there is need of a durable, massive, smooth surface which
releases clay easily and which doesn't shed spinters or plaster bits. I
suspect that the closest to this that I have seen in the discussion so far
was the marble slab. However, it too broke. The plan to back it up with
plaster seems perfectly sensible to me. In Quebec, where I grew up, there
were some granite quarries. The stone they were quarrying was dense,
polishable and very strong and durable, being mostly quartz and feldspar
(orthoclase). Sort of clay in waiting. It strikes me that a granite slab a
couple of inches thick on a sturdy stand, perhaps with a tiltable top, would
be just about perfect. You could slam and scrape and wedge to your heart's
content on that.
Failing the granite slab (easy to get in Vermont, for instance), I guess a
marble or other facing stone slab from any monument maker or stone mason
would serve. Or even a piece of kitchen counter top. If it were not quite
thick enough, a backing of a couple of inches of plaster would help. Then
the plate (it would be quite heavy) could be mounted on a sand bag to permit
it to be set to the right angle, and the whole thing mounted on a sturdy
stand or bench. The sand would also help to absorb shock from the slammers.
The greatest virtue in such a table is probably its mass. The clay mass
will experience the greatest deformation and mixing as it is slammed into a
mass much greater than it. Hence the thick slab and surdy stand: you can't
get much more massive than Mother Earth! I bet that such a wedging table
would serve as long as most of us will be wedging, and would be efficient
and easy to use as well.
Maybe I'll try to pick up a piece of granite when I go home for Christmas...
Bye, Gavin
R Wuetherick on mon 23 dec 96
Cover your wedging table with Canvas Carl!
> Also, I've recently been told be careful with clay around plaster as
plaster
> will explode in the firing. How do you protect your wares from getting
> plaster in them while preserving the absorbance of the surface? I would
think
> with a cracked surface would come small fragments of plaster which would
> pollute your clay and make it dangerous to fire with other peices. Are
there
> ways of containing the plaster in the wedging surface so it doesn't get
out?
> Are there alternatives to plaster that are still quite absorbant?
Steve Williams on mon 23 dec 96
Carl Ross wrote:
>
> ----------------------------Original message----------------------------
> In a message dated 96-12-22 11:01:41 EST, mjbmls@imt.net (Marcia Selsor &
> Matt Benacquista) writes:
>
> << Somewhere this slam type of wedging is being taught(?) >>
>
> Dear Marci,
>
> I've always been tuaght to slam it down a few times while wedging, but only
> on the corner of the table where the sturdy leg is. It's to "get the
> molecules moving" after its long sitting.
>
> Also, I've recently been told be careful with clay around plaster as plaster
> will explode in the firing. How do you protect your wares from getting
> plaster in them while preserving the absorbance of the surface? I would think
> with a cracked surface would come small fragments of plaster which would
> pollute your clay and make it dangerous to fire with other peices. Are there
> ways of containing the plaster in the wedging surface so it doesn't get out?
> Are there alternatives to plaster that are still quite absorbant?
>
> Confused in Phillips,
>
> Carl
>
> Would a thick bisque slab work or woul the clay
Carl,
I use 4 concrete pavers (14x14x3 +or-)butted together edge
to edge to form a larger square. A frame around them keeps
them together. This arrangement has worked for ten years or so
and appears to be ready to go another ten.
Steve Williams
In beautiful downtown Matney NC USA where we used to have a store but it
closed, and nobody pays much attention to that stop sign.
Happy Holidays everybody!
Marcia Selsor & Matt Benacquista on tue 24 dec 96
Carl Ross wrote:
>
> ----------------------------Original message----------------------------
> In a message dated 96-12-22 11:01:41 EST, mjbmls@imt.net (Marcia Selsor &
> Matt Benacquista) writes:
>
> << Somewhere this slam type of wedging is being taught(?) >>
>
> Dear Marci,
>
> I've always been tuaght to slam it down a few times while wedging, but onlyon
That is an interesting theory. Thanks for the info on the origing of the
idea. I think it is a bit of a myth, though and some big Montana ranch
kids can really slam it down.
>
> Also, I've recently been told be careful with clay around plaster as plaster
I know that plaster can blow up clay because it absorbs the moisture
from the clay. That is its blessed quality. I instruct the students
to avoid gouging the large plaster molds (slump molds) as well as the
wedging table. I sponge off the wedging table after classes although the
students use a plastic scraper to clean off dry flakes before wedging. I
tell them to throw out any clay that gets a little plaster in it or to
get the plaster out of it. We have a very high success rate with rare
blow ups few to none/per semester.
>
Are there alternatives to plaster that are still quite absorbant?
In Spain where I teach a summer workshop, there is a low concrete slab
weding table with a very smooth surface. It is cemented into place.
I liked this surface. It was absorbant, too. I have used the concrete
floor in the shop a la Reitz style wedging large lumps.
>
> Would a thick bisque slab work or woul the clay
I don't think a bisque surface would be very sturdy. I personally like
plaster. Plaster and clay work well together for many purposes. Just
keep chips out of the clay.
> Confused in Phillips,
>
> Carl
-- Marcia in Montana
Marci Selsor
Matt Benacquista
http://www.imt.net/~mjbmls/
mjbmls@imt.net
KDrescherg on tue 24 dec 96
I have made a wedging table with only 2 1/2" of plaster 24"x24" at a
heigth of about 30". the base is made as solid as I could get it- 2x4
construction. This has lasted me about 4-5 years.
I now have it outside and it has molded I'm wondering if this mold is good
mold or bad mold-- what effect wil it have on my clay. Also I have always
suspected that plaster can leak through my canvas covering though I have
no proof. Plaster does work well as a wedging surface you can feel the
moisture level drop in your clay as you wedge- which I am sure is the
point.
Bob Freitas on tue 24 dec 96
I've been lurking around quietly for awhile, enjoying all the info and
comments, but I'll throw my two cents in on this subject. At college, we
had some minimal contamination from the wedging table and tried a piece
of heavy canvas over it. The result was smaller bits of plaster worked
into the clay. Popouts quite near the surface, small, but bothersome.
When I set out on my own, I built a table with a three by two box at the
top, and filled this with stucco mix trowled smooth. It's a bit heavy,
but has served for about 15 yrs with no great wear, no popouts, and has
been moved to four different houses. Was even left outside in the
weather (in Calif.) for a couple of years. I may never make another!
Happy Holidays!
Bob
in soggy central California
DABBERT@aol.com on thu 26 dec 96
We have never used plaster, in our 25 years working with clay, for a wedging
table because of all the problems associated with it. We found that slate
works well. Use a slab about 1 1/2" to 2" thick. The slate is the same
stone used in pool table tops and it also absorbs water like plaster.
Phil Davenport on tue 31 dec 96
Concerning plaster and clay, you could cover the plaster with canvas and
wedge clay on the canvas.
Another solution is to have a top made out of cement and cover that with
canvas.
In either case the canvas will protect the clay from contamination.
Phil Davenport
Garland, Tx
On Mon, 23 Dec 1996, R Wuetherick wrote:
> ----------------------------Original message----------------------------
> Cover your wedging table with Canvas Carl!
>
> > Also, I've recently been told be careful with clay around plaster as
> plaster
> > will explode in the firing. How do you protect your wares from getting
> > plaster in them while preserving the absorbance of the surface? I would
> think
> > with a cracked surface would come small fragments of plaster which would
> > pollute your clay and make it dangerous to fire with other peices. Are
> there
> > ways of containing the plaster in the wedging surface so it doesn't get
> out?
> > Are there alternatives to plaster that are still quite absorbant?
>
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