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throwing out hard clay

updated sun 20 feb 05

 

Milla Miller on sat 29 jan 05


Having spent a good bit of time in the past at Penland and Arrowmont POTTERY
PROGRAMS I was also horrified at the amount of dryed out clay sent to the
landfill.I asked to have it to recycle myself, and they refused.
Margaret

dennis mclaughlin on sat 29 jan 05


I have a very fast efficient way of reprocessing clay scraps. Besides a 5'X7" canvas tarp, a heavy duty 20-30gal. container with moistened clay scraps (not excess water on top of the clay) and the clay body in a dry powdered form ( a similar clay body works too), one needs the energy to foot wedge it until it's ready to cut up into 10-15lb chunks and hand wedge. I produce about 350lbs of clay ready to throw in about an hour and one half. I never use a pug mill.

Milla Miller wrote:Having spent a good bit of time in the past at Penland and Arrowmont POTTERY
PROGRAMS I was also horrified at the amount of dryed out clay sent to the
landfill.I asked to have it to recycle myself, and they refused.
Margaret

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John Britt on sat 29 jan 05


Margaret,

I am sorry to hear about your experience, but when I was at Penland I
always allowed people to take their clay home and recycle. I cannot think
of any reason that you would be prevented from taking clay home to
recycle. (Now recycling on-site, in the mixer is a problem of safety.)
Also, everyone was provided a plaster bat to assist with hand recycling.
Much of the clay is saved by the CORE students but is true that there is a
lot thrown out.

The large volume of clay used (I think we used about 30 or 40,000 pounds a
year), as well as space and time constraints made large scale recycling
impossible. This is the same reason that they no longer make all the clay
they use at Penland on-site. It is simply too costly to have a person or
several persons make the clay, bag it and store it for each class. There
are quality and efficiency issues to be considered too. Then, there is the
contamination of high-fire clay with low-fire clay - that is simply
disastrous. Everyone is in favor of recycling and wants to recycle until
they have to be the one to do it on a large scale. The first hundred or
two hundred pounds are ok, but it is after the 10,000th pound that it gets
to be a chore.

There are also problems with recycling that no one has mentioned yet.
Don=92t know if anyone heard the lecture on clay at NCECA last year, but he
talked about the reason for bloating and gassing in recycled clay. (In
short, clay that is improperly mixed/ blunged will have particles of
feldspar which cling together in a group and disproportionately melt that
area, causing a bloat or pinhole. Probably Ron or someone can explain it
better.) So recycling does not always make better clay. Sometimes it makes
it worse, especially if you don=92t know what you are doing.

Also, when beginners throw they wash away more of the fine particles into
the water as the clay is on the wheel being sponged with water much longer
than with advanced students. This makes a very fine slip which, if
recycled, can cause cracking problems. Also, when people recycle a large
batch they often add a scoop of fire clay, ball clay, silica, feldspar and
grog to the recycling mix to help dry it out. This is often done with a
clay body that they don=92t have a recipe for so the recipe is constantly
changing. This can cause fit problems with glazes, as well as dunting (too
much silica) or pop- outs (because they don=92t sieve the raw materials) or
other many other unnecessary problems. Not to mention sponges, needle
tools and chamois getting in to the mix. If they have the recipe they
often take short cuts and just take a scoop of fire clay and two scoops of
ball clay, etc. (who know how much is in a scoop and if it is consistent
done). And they might wear the dust mask for a while and, then, after a
short time, decide it is too hot and take it off. Did I mention that the
workshop participants then have to wedge the fresh recycled clay longer
because we don=92t have a pug mill.

So if you put in all those considerations, time, machinery, space,
consistency, contamination, safety, complaints, workshop experience, etc.,
you can see why people don=92t always recycle in group situations.

Sorry but you can see I have endured a bit of physiological trauma around
this subject,

John Britt
www.johnbrittpottery.com

Ivor and Olive Lewis on sun 30 jan 05


Dear Margaret,
After you have prepared you clay by treading and wedging how long do
you let it rest before you reuse it? Is it "Firm" plastic or "Soft "
plastic. How do you store it?
Best regards,
Ivor Lewis.
Redhill,
S. Australia.

lynhunter on tue 15 feb 05


Dennis, I am relatively new at throwing pottery, and I have been studying
under a wonderful potter with 38 yrs. of experience, but I wanted to ask you
, to explain to me what you do to get the large hard lump of clay into a
powdered form. I bought a gas kiln recently and the man gave me some clay,
and I didn't know that the bag was ripped , so after a time it dried out. I
hate to throw clay away. Thanks, Lynn Hunter
----- Original Message -----
From: "dennis mclaughlin"
To:
Sent: Saturday, January 29, 2005 11:07 AM
Subject: Re: throwing out hard clay


> I have a very fast efficient way of reprocessing clay scraps. Besides a
5'X7" canvas tarp, a heavy duty 20-30gal. container with moistened clay
scraps (not excess water on top of the clay) and the clay body in a dry
powdered form ( a similar clay body works too), one needs the energy to foot
wedge it until it's ready to cut up into 10-15lb chunks and hand wedge. I
produce about 350lbs of clay ready to throw in about an hour and one half.
I never use a pug mill.
>
> Milla Miller wrote:Having spent a good bit of time
in the past at Penland and Arrowmont POTTERY
> PROGRAMS I was also horrified at the amount of dryed out clay sent to the
> landfill.I asked to have it to recycle myself, and they refused.
> Margaret
>
>
____________________________________________________________________________
__
> 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.
>
>
>
> ---------------------------------
> Do you Yahoo!?
> Yahoo! Mail - Find what you need with new enhanced search. Learn more.
>
>
____________________________________________________________________________
__
> 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.
>

Cindy in SD on thu 17 feb 05


Dear Lynn,

So, this clay is dry as a rock? I might get roasted for this, but my
advice is to toss it out. If you're determined, take a big hammer and
pound it down to smaller pieces, then put it in a bucket and add some
water, cover with a wet towel and some plastic and let it sit until it
softens. At this point, either add more water if it's too dry, or let it
sit until it firms up. Stir it once in a while. Once it gets to around
oatmeal consistency, you can wedge it in with new clay. It's messy, but
it does work. Just don't add too much at a time, or your new clay will
become too soft. It's easier to throw clay that is on the soft side of
workable, and most of the bagged clay I get seems a bit stiff for my
tastes, so I end up adding gloopy scraps. But I have a pug mill, so it's
no trouble.

Meanwhile, buy yourself some good clay so you can carry on having fun
while the rock slakes down. ;)

Best wishes,
Cindy in SD

Mike & Diane on sat 19 feb 05


For lack of a better term "reconsituting" hard clay is actually a snap!
Learned this from a gifted fourth grader and her science fair experiment.
It works best for large lumps or bricks of clay. Put it in a strong plastic
bag, pour a couple cups of water into the bag. Twistie tie the bag tight.
Immerse it in a bucket of water so the water fully covers the lump of clay
in the tightly tied bag. The optimum time is 12 hours. You can leave it
longer but the best results come out after 12 hours.

She called this "hydrostatic pressure" and I've used it consistently for
good results. The pressure from the water outside the bags pushes the water
evenly into the clay.

Diane Rae
Royal Thrown Pottery
Great Falls, Montana

Itchin' to get more use out of her new L&L Easyfire...what a joy!