iandol on mon 29 jan 01
I have a quantity of clay that needs to be reclaimed and I was wondering =
which is the best water to use, bearing in mind that our municiple =
supply is heavily contaminated by salt and additives used to stabilise =
and sterilise it.
When you mix plastic clay for throwing, extrusion or other processes, =
what are the qualities you should seek in the water that you use.
For example, is rain water or water derived directly from snow better =
than spring water or river water? Does water from a deep well have any =
advantages?
Does the underlaying geology influence bore, well or spring water in =
ways which benefit the development of plasticity? Has water which runs =
out of limestone caves properties that make it superior to water derived =
from sandstone aquifers?
What happens to the chemistry of a clay as it weathers under the =
influence of rain, snow and ice?
What are your opinions about these ideas. Or am I thinking nonsense =
again, in that the quality of water is immaterial.
Looking forward to your discussion.
Ivor Lewis. Redhill, South Australia.
Les Crimp on mon 29 jan 01
Ivor -
I find this interesting as I have often wondered about water and clay, too.
One of my pottter friends ( my mentor, really) advised me to keep all the
water that surfaced in my slip buckets that I keep to reclaim the clay from.
When there is enough water separated from the clay I pour it into a separate
bucket and set it aside.
When I smash up dried clay (trimmings, etc.) and put it in a bucket to slake
I use the used clay water to slake the clay with. As to any scientific
reasons for doing this I have no answers as I am not a scientist - but I
seem to get very good plastic clay each time I dry and wedge and then knead
the clay.
Strictly a laymans approach and results. I am also looking forward to
discussion on this matter.
Best regards,
Les Crimp in Nanoose Bay, B.C. (on that Island in the Pacific)
lcrimp@home.com
Autumn Downey on mon 29 jan 01
Hello Ivor,
I'm a little obssessive about water and will read replies that you get with
interest.
In Yellowknife (NWT) the water is quite soft and relatively free of
minerals. Where I pot in Saskatchewan, the water has lots of Ca and Mg
(though not much iron).
I do notice that the slip formed from throwing pots in Sask is very thick
and flocculated. And I decided that this slip was quite useless for
attaching handles to pots - practically repelled them. I started using
water with some trisodium phosphate in it for handles and this seemed to
work better.
Also the plaster batt that I dry this slip in grows furry crystals and
looks like a chia pet.
In Yellowknife, the only difficulty is with porcelains or a white stoneware
that must have some of the same materials as porcelain. Slip from this
clay deflocculates and becomes cement-like in our water buckets unless we
add a little Epsoms salts. Other clays seem fine.
Anyway, the difference in water is quite noticeable, though perhaps more so
in glazes.
I'd think that purer water in clay might be less trouble over all.
Autumn Downey
Yellowknife, NWT
At 01:26 PM 2001-01-29 +1030, you wrote:
>I have a quantity of clay that needs to be reclaimed and I was wondering
which is the best water to use, bearing in mind that our municiple supply
is heavily contaminated by salt and additives used to stabilise and
sterilise it.
>When you mix plastic clay for throwing, extrusion or other processes, what
are the qualities you should seek in the water that you use.
>For example, is rain water or water derived directly from snow better than
spring water or river water? Does water from a deep well have any advantages?
>Does the underlaying geology influence bore, well or spring water in ways
which benefit the development of plasticity? Has water which runs out of
limestone caves properties that make it superior to water derived from
sandstone aquifers?
>What happens to the chemistry of a clay as it weathers under the influence
of rain, snow and ice?
>What are your opinions about these ideas. Or am I thinking nonsense again,
in that the quality of water is immaterial.
>Looking forward to your discussion.
>Ivor Lewis. Redhill, South Australia.
>
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Autumn Downey on tue 30 jan 01
>but I was always discouraged when
>trying to recycle porcelain scraps (no pugmill). Always end up with cement
>in the bottom of the bucket, and then after drying the slip and wedging up,
>get dry crumbly bits in the plastic clay.
Hi Jean,
I'm pretty sure this would work for you. We add about 1/2 tsp of the E S
solution to half an ice cream bucket of throwing water and this is enough
to keep the clay from caking.
If your scaps are small and completely dry , they might dissolve ok in the
slip (throwing water) - or you could add water with ES to them when they
are dry.
It ought to work, although I suppose too much ES from much recycling might
change the throwing qualities of the clay slightly.
For mixing, Robert Fournier's book suggests 3 parts water to 1 part salts,
but we do it by weight at our Guild and I think that the solution is more
concentrated.
Good luck.
Autumn Downey
(Yellowknife, NWT)
Jeanne Stolberg on tue 30 jan 01
(excerpt from: Autumn Downey
Yellowknife, NWT)
In Yellowknife, the only difficulty is with porcelains or a white
stoneware that must have some of the same materials as porcelain. Slip from
this
clay deflocculates and becomes cement-like in our water buckets unless we
add a little Epsoms salts.
Sorry, I'm going off on a tangent here, but I was always discouraged when
trying to recycle porcelain scraps (no pugmill). Always end up with cement
in the bottom of the bucket, and then after drying the slip and wedging up,
get dry crumbly bits in the plastic clay. Spent much time
scraping the cement-like mass and trying to make it homogenous with the
water with scrapers and fingers. Before wedging, would spread out the clay
on my plaster wedging table and try to mix in (squish and smear) any
remaining little bits (Even though the scraps had soaked for several weeks)
to try to avoid finding them later when throwing. So would adding epsom
salts to the bucket solve this problem? It was so time-consuming and
frustrating that I gave up on porcelain. Will have to try it. Anybody out
there have some suggestions? BTW, our water supply is rain water collected
off our roof, stored in a 3000 gal.cistern (swimming pool) under the house,
since we're not hooked up to town water supply. We get plenty of rain - no
shortage here.
Thanks,
Jeanne S. in Sunny Sitka by the Sea. (Ha Ha, the joke is, it's hardly ever
sunny here, the words just go together well), Alaska, USA
Milton Markey on tue 30 jan 01
Hi Ivor!
I've used water from all sorts of sources, including rivers, lakes, and other
fresh water sources. I've also mixed glazes, made slips, and mixed clay in
regular tap water, and brackish water. There seems to be no difference in the
outcome. Water is water, unless, of course, you're too close to a nuclear
waste site, or an ocean tainted with oil from a tanker collision, or water
unusable due to identified contaminents.
Milton NakedClay@AOL.COM
Yucca Valley, CA
iandol on wed 31 jan 01
Dear Milton Markey=20
Thank you for your response. I suggest we agree to disagree. Having =
washed in water from a limestone district as well as being brought up =
where water was filtered through beds of gritstone I know there Water =
and Water. Washing in Hard Water is a pain. Mineral content can vary and =
some human deficiency problems come about because of the absence of some =
elements.
That said, it is interesting to learn that the Sodium content of =
brackish water, here I assume you mean river water mixed with sea water, =
has no effect on the plasticity of your clays.
Again, thank you for your information. Best regards,
Ivor
iandol on wed 31 jan 01
Dear Les,
I do much the same thing, regarding the water which has been in contact =
with clay as having better lubrication qualities than fresh water. So =
far I cannot explain it.
There is some information which has come into my hands and this is a way =
of following the ideas through. But I think the Clay Makers have to come =
in on the discussion because it is the water which they use which is the =
most influential when the clay is first mixed. I know some of them will =
dig clay which is already moist and just pan mill that, with the =
additions of sand, grog, fluxes and so on before they pug and bag it.
It may take a while to sort my thoughts out on this but any information =
about the water being used and its mineral salt content would be =
helpful.
Good to hear from you again.
Best regards,
Ivor Lewis. Redhill, South Australia=20
Ron Roy on thu 1 feb 01
Hi Ivor,
Here are my preferences and the reasons.
Rain water first - it will probably be slightly acidic and have some
"starter" in it if it's off a roof and has some organics like bird
droppings. The clay will get "aged" faster.
Distilled would theoretically add nothing but at least you would know what
you started with - little or no mineralogy. You can then add some throwing
slurry to hurry up the aging. Adding some well aged clay to fresh clay
alway helps the aging go faster - just like starter in a compost heap.
Depending on the quality of the well water - if it's alkaline I would not
recommend it - works against the aging process. Well water usually has
minerals and sometimes they change with the season. I would want to know
what minerals are present at any given time.
Limestone would effect aging and plasticity in a negative way I would think.
RR
>I have a quantity of clay that needs to be reclaimed and I was wondering
>which is the best water to use, bearing in mind that our municiple supply
>is heavily contaminated by salt and additives used to stabilise and
>sterilise it.
>When you mix plastic clay for throwing, extrusion or other processes, what
>are the qualities you should seek in the water that you use.
>For example, is rain water or water derived directly from snow better than
>spring water or river water? Does water from a deep well have any
>advantages?
>Does the underlaying geology influence bore, well or spring water in ways
>which benefit the development of plasticity? Has water which runs out of
>limestone caves properties that make it superior to water derived from
>sandstone aquifers?
>What happens to the chemistry of a clay as it weathers under the influence
>of rain, snow and ice?
>What are your opinions about these ideas. Or am I thinking nonsense again,
>in that the quality of water is immaterial.
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
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