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reclaiming clay- small scale

updated fri 24 oct 03


Tamara Williams on sun 19 oct 03

I'm trying to figure out how to reclaim my clay. I have some Plaster of =
Paris that I bought from Michael's. Would that work to make plaster =
bats? Or do I specifically need #1 pottery plaster? Or any other =
ideas? Thanks


Alex Robinson on mon 20 oct 03

I'm also on a small scale and here's what I've done. Bear in mind I've made a couple of these things since I do agateware and need to keep various colors from contaminating each other.

I have an old cat litter bucket next my wheel for trimmings and other slop such as my very clayed throwing water once it's too thick.

Using standard plaster of paris (the el cheapo kind from the nearest hardware store) I made plaster containers. Here's how I made them.

I bought two paint mixing buckets, the plastic disposable kind from that same hardware store. I bought one about a foot wide and the other about 10 inches wide. Put something that's a couple of inches tall in the bottom of larger one then set the smaller one inside. Punch holes near the top so you can stick skewers through so it will hold the smaller one hanging in midair inside the larger one. The thing you had sitting at the bottom of the larger one was to create this measurement. You can now take it apart, empty the buckets, spray it all with cooking oil so the plaster doesn't stick, and put them back together so the little bucket is hanging inside the larger bucket.

Now pour plaster inside the larger bucket around the littler bucket. The skewers should keep the little bucket in place so it doesn't float up and the plaster will be forced to mold around it.

Once it has set and you get all the buckets pulled off the plaster, you should now have a small plaster bucket to recycle clay in. Dump your slop in this and let it sit for a day or two to get rid of most of excess moisture (the plaster will draw it out) but without over drying it like it might on a bat. Then dump it out on a bat and slice to let the insides get exposed to air for a couple of hours and it's ready to wedge.

I made my 2 buckets over a year ago and they are holding up pretty well. Might have to replace them soon. If you have extra plaster when you're pouring, you might want to pour into a tall cylinder. Then you can stick the tall cylinder of plaster into the middle of the slop to have one more thing pulling out moisture if you're in a hurry.

Good luck!

---------- Original Message -------------
Subject: Reclaiming clay- small scale
Date: Sun, 19 Oct 2003 12:52:36 -0400
From: Tamara Williams

I'm trying to figure out how to reclaim my clay. I have some Plaster of Paris that I bought from Michael's. Would that work to make plaster bats? Or do I specifically need #1 pottery plaster? Or any other ideas? Thanks


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M. Alex Robinson

Ann Brink on mon 20 oct 03

That will work fine. I would lay a piece of fabric on your plaster before
pouring your reclaim on it. If you work with several kinds of clay, have
fabric pieces dedicated to each kind. If you want to wash your piece of
cloth, let it get totally dry before soaking in a bucket for a while.

If you want to reclaim larger amounts at once, you can lay a large piece of
strong cloth right on the ground (I like polyester knit from thrift shops),
pour a bucketful of clay on it, pick up the sides to cover your clay for a
few days. The ground wicks the water. You will notice the edges get firm
first. At that point, you can sort of push the edges in to mix with the
softer clay. Just check for pill bugs before you bag it!

Rather than let it all get too firm, I sometimes pick it up when it's
fairly soft and let it finish firming in the studio, on a bat with a cloth
on it. I stand thick slabs on edge and cover them with another cloth, for
uniform slow drying. The reason for the cloth is my bats are particle board
and all have old clay residue on them, which I might not want in the new
clay. Hope this isn't a lot more than you wanted to know.

Ann Brink, Lompoc CA

----- Original Message -----
From: "Tamara Williams"

I'm trying to figure out how to reclaim my clay. I have some Plaster of
Paris that I bought from Michael's. Would that work to make plaster bats?
Or do I specifically need #1 pottery plaster? Or any other ideas? Thanks


Send postings to

You may look at the archives for the list or change your subscription
settings from

Moderator of the list is Mel Jacobson who may be reached at

Milla Miller on mon 20 oct 03

I have found for reclaiming clay on a small scale a huge plaster bowl, 2"
minimum thich on the sides works well.I make a hump of solid clay[if I don't
have a big flexible plastic bowl, from thrift or dollar store] and use scrap
plywood wiped with vaseline or sparyed wd40 held with clamps into a box shape
on a formica ,glass or smooth lubricarted surface with a fat coil pressed
about the outside base of the box shape wqith the upside down bowl shape inside.

I generally use the U.S.Gypsum calculator to figure the plaster mass based
on the box dimesnsion less the bowl dimension to get tthe ''exact'' quantity of
plaster needed.You can also ''guess-timate'' and use the over in smaller
plastic lubricated bowl forms for hump molds,poured to any depth leftover.

I make the plaster using water in a lubricated plastic pail with coolish
water in first and adding plaster sieving it thru my hand,to eliminate lumps,
until the peaks form then let it set a minute or so before stirring so it is
thoroughly wetted,then immediately pour over the inverted bowl shape until the
plaster is at least 2'' deep or more over the bottom of the inverted bowl clay
form.Tapping under the table with a soft rubber hammer helps eliminate
bubbles.Add more clay about the base if any leaks appear.

Wait until the plaster has gone thru the ''hot'' stage and cooled before
opening the clamped enclosed form.Remove the board sides and invert and remeove
the clay and allow to dry over level slats or open mesh or wire shelving to
allow the inside to dry evenly.I try to allow it to dry a week.It can also
be used as a form for handbuilding when not drying clay.Clean up the edges with
a rasp while it is still wet but hardened.

More than one is nice also if one is too wet.It can be used right next the
wheel to pour the throwning slops . I pour the slops over the trimming scraps
and will wedge the results when the mix reaches a managable stage.

The clay used to make the ''model'' bowl I keep in a heavy plastic bag and
clearly label for use for ''model making only'' due to the fact that the
plaster may have contaminated it for throwing /handbuilding as it would explode
them out in a firing.

This system is easy to use if you are able to still wedge your clay and have
rooom for the ''bowls'',and wish to mix plaster.Mix the plaster outside ,if
possible, and hose down .The plaster is ok that you mention but more expensive
that way.Check your building suppliers to inquire about a better source #1
Pottery Plaster or even moulding plaster will work and make sure the supply is
fresh and dry and keep plaster in a plastic outer bag or even additionally a
dry covered barrel.It is not well kept for more than close to 6 months
varying by environment and humidity.Old plaster will not set up satisfactorily and
often may have lumps in the dry form.
If you cannot make the ''box'' over the plaster you could make the plaster
mix and when it starts to slightly thicken just scoup ti over the inverted clay
bowl form to a 2'' thickness.You could reinforce the structure by adding
plaster soaked strips of cotton sheeting-like fabric or those medical cast
plaster bandages craft stores sell for sculptural uses onto the outer surface of
the bowl form..however this is just for added strength not necessary.

Have fun.Hope this helps.

Eleanor on tue 21 oct 03

Dear Tamara,

Years ago, BC (Before Clayart), when I didn't know there were
different kinds of plaster, I bought a bag in my local hardware
store, followed the mixing directions on the bag and made a bunch of
bats by pouring the mix into metal pie plates. The bats are still
useable except for an occasional chip which gets into the clay if I'm

I collect cuttings, bits and pieces of clay, sometimes even larger
bone dry pots which I've decided not to fire (I break these up) in a
big old-fashioned basin (enameled metal bowl). When the bowl is about
half full, I add throwing water which has become very slippy, making
sure to scrape out the stuff which has settled to the bottom of the
throwing water bowl---I understand that clay loses some of its
components during throwing, they wind up in the throwing water, so
this method restores them.

The clay is now quite wet. I wait until it has dried out to a very
soft consistency at which point I squoosh it around with my hands to
"blend" it and empty it onto one end of my wedging board where I
leave it to dry out some more--this takes a day or two or three
depending on the humidity. When the clay is ready to handle, I scrape
it up and begin to knead it. After a while, the clay becomes smooth
and even, a little too soft for throwing maybe, but it can be formed
into balls, left to dry out a bit more, and re-used. My clay
(Tuckers) is very good for throwing right out of the bag, but
sometimes I think the reclaimed clay is even better.

My wedging board is a 19.5x19.5x1.75 inch concrete paving stone,
which sits on top of a storage cabinet with a cutting wire installed
next to it. The surface is smooth and it is just about as absorbent
as plaster. A bench knife, used in bread baking to scrape up dough
from the kneading surface, makes an excellent clay scraper.

I find that rather than spending time, money and effort constructing
something which may eventually break or chip, my method works and
gives me more time to make pots.

Eleanor Kohler
Centerport, NY
small-scale potter AKA dabbler

william schran on tue 21 oct 03

Tamara wrote:>I'm trying to figure out how to reclaim my clay. I
have some Plaster of Paris that I bought from Michael's. Would that
work to make plaster bats? Or do I specifically need #1 pottery

I have a wedging board with a 2x4 frame and 1x2 slats on the bottom
(used solid piece of plywood when I poured the wet plaster into the
frame, then replaced plywood with slats when plaster dried), that's
about 30"x30" and 3&1/2" deep. I also use this to reclaim my slurry.
At school I poured plaster into disposable aluminum foil roaster
pans. Students can sandwich scrap clay & slurry between 2 of these
and reclaim the clay by end of class.
Depends on how much clay you plan to reclaim to determine size, but
I'd recommend #1 pottery plaster over plaster of paris which I think
you'll find to be too soft, thus easily nicked getting plaster into
your clay.

Derrick Pottery - owner - Wesley Derrick on wed 22 oct 03

I purchased one of those "see-thru" storage bins from WalMart...the
kind with the snap-on plastic lid (mine's green ;P) and this lid happens
to have a small raised box on top of it for venting...??? not sure what it's
intended use is but works great for keep a little movement of fresh air but
not so much that it dries out too fast.
All my trimmings from footing pots go directly into this bin. Larger pcs.
that I have in my wheel trays after throwing I put in a dish (whatever
kind) to dry as well I put all my large scraps from slab work etc. in this
dish until they are dry enough to crush into smaller pcs. and then they are
added right on top of the existing "sludge" in the bin. I keep it wet with
the throwing water I have left over after it's too thick to be of use for
throwing...empty off most of the top water and then two quick stirs and
pour it on...I keep it the consistancy of pudding almost with just a little
water standing here and there ....mix it ever day or two to keep the smell
down...if the smell becomes too bad...2 or 3 drops of bleach will fix it
Once I'm ready to "reclaim" it I scoop it up and spread it out on a plaster
slab I made of local harware store plaster poured in a frame I made. I took
an old plastic laminate counter top material, glued (4) 1" high strips of
wood into a rectangle shape (2 X 3-1/2 feet) on top of it, took about 4
boxes, and then poured the wet prepared plaster in the frame..let it
dry...turned upside down to release it and presto...a super nice plaster
slab with a fine smooth surface to harden up the clay on. If the slab is
bone dry it only takes me 2-3 hours to have 10 to 15 pounds of wedgeable
clay. Nice plastic clay too~~!!
This system has worked GREAT for me a small time raku potter. Total
material / supplies mentioned takes up only about 3 cubic feet: A plus for
Be careful to not get any plaster in your clay ..wait until the edges are
good and non-tacky and when the whole slop that you put on the plaster slab
can be lifted at the corner and picked or rolled up and off without it
tearing badly....usually this is a perfect consistancy for wedgeing.
Hope all this helped a little.
Good luck.
......and -- please---forgive any spelling's late and I'm not
re-reading this rambling idiot.

Wesley in Raymond MS.
Derrick Pottery

Susan Fox-Hirschmann on wed 22 oct 03

I found that kitty litter trays are just the right size to make a plaster
slab to dry clay on....removes easily, and cleans up easily, just work quickly
with the #1 Pottery Plaster and shake, shake to get those air bubbles out. If
you have not worked with this before, Frith/s book on mold making will be
helpful. (Great instructions of slaking, mixing and proper proportions of water
to plaster)
Good luck!
Annandale, VA

Alycia Goeke on thu 23 oct 03

hi tamara,
if my clay has gotten too hard in the bag, or i have a bunch of scraps, i
fill up a clay sack full, add a cup of water, close the bag tightly, and submerge
it in a five gallon bucket of water overnight. next day, i pull the bag out
and bang it around on the floor to kind of condense everything and then i open
the bag. i use my wire to cut 2-3" slices of the clay and i place those on
some plaster bats i have from an old kick wheel. as i work in my studio, i
occasionally turn the clay and within a few hours, it is ready to wedge and use.
make sure if you use plaster that your surface area is in good condition so you
don't have to worry about getting chips of plaster in your clay body.
happy potting,