Dave Finkelnburg on fri 23 jul 04
Ben,
Yes, some of the rest of us noodle away on such clay equipment one
someone else's time. :-) It's a hazard with clay!
A filter press is designed the way it is for a reason. To be effective
a filter press needs to work with a large surface area for the volume of
clay slurry being filtered. A slurry of fine solids, such as a clay slip,
is basically impermeable to air. About all you can do is create a pressure
differential and wait for water to flow to the area of lower pressure. With
a filter press the first slurry to hit the filter cloth is really the
"filter." This first layer of filter cake filters all the slurry behind it.
Still, it only works for a limited thickness of clay slip.
Speaking of filters, you are planning to filter your fry oil, right?
Used oil, unlike home heating oil, will have lots of fine solids that will
plug your burner orifices otherwise.
Good potting!
Dave Finkelnburg
----- Original Message -----
From: "Ben Shelton"
Sent: Friday, July 23, 2004 12:35 PM
> I was reading Harry Davis's book and ran across the chapter on the vacuum
> operated filter press. Novel idea, especially for those with a good vacuum
> pump on their pugmill but I wondered if the vacuum could be applied to the
> clay to suck the water out rather than used as a means to squeeze the
water
> out.
> I had imagined a cloth lined frame of sorts, into which clay slurry could
> be poured. The vacuum applied to the underside and a trap or reservoir for
> the water to collect in.
> Anybody ever tried it?
> Does anybody else have these wierd ideas while at their "Day job"?
Ben Shelton on fri 23 jul 04
I was reading Harry Davis's book and ran across the chapter on the vacuum
operated filter press. Novel idea, especially for those with a good vacuum
pump on their pugmill but I wondered if the vacuum could be applied to the
clay to suck the water out rather than used as a means to squeeze the water
out.
I had imagined a cloth lined frame of sorts, into which clay slurry could
be poured. The vacuum applied to the underside and a trap or reservoir for
the water to collect in.
Anybody ever tried it?
Does anybody else have these wierd ideas while at their "Day job"?
Ben
Hank Murrow on fri 23 jul 04
On Jul 23, 2004, at 11:35 AM, Ben Shelton wrote:
> I was reading Harry Davis's book and ran across the chapter on the
> vacuum
> operated filter press. Novel idea, especially for those with a good
> vacuum
> pump on their pugmill but I wondered if the vacuum could be applied to
> the
> clay to suck the water out rather than used as a means to squeeze the
> water
> out. I had imagined a cloth lined frame of sorts, into which clay
> slurry could
> be poured. The vacuum applied to the underside and a trap or reservoir
> for
> the water to collect in.
>
> Anybody ever tried it?
> Does anybody else have these wierd ideas while at their "Day job"?
Dear Ben;
One of my teachers found that clay slurry left out to freeze developed
little upward growing stalagmites of ice, When he brushed off the
stalagmites and thawed the clay, he found that it was just right for
wedging and very plastic.
Cheers, Hank
murrow.biz/hank
Gary Navarre on sat 24 jul 04
Ben asked:
I was reading Harry Davis's book and ran across the chapter on the vacuum
> operated filter press. Novel idea, especially for those with a good vacuum
> pump on their pugmill but I wondered if the vacuum could be applied to the
> clay to suck the water out rather than used as a means to squeeze the
> water
> out.
>
> I had imagined a cloth lined frame of sorts, into which clay slurry could
> be poured. The vacuum applied to the underside and a trap or reservoir for
> the water to collect in.
>
> Anybody ever tried it?
> Does anybody else have these wierd ideas while at their "Day job"?
>
> Ben
>
Hay Ben and Crew,
Some years ago just before I dismantled the studio I wanted to make
some Porcelain to save just in case I found a way to work again, like
now. Not having the luxury of heavy equipment I decided to replicate
Cardew's process for dewatering/stiffening (pp. 84-86, "Pioneer
Pottery") and built a dewatering tray lined with canvas. It worked
great if one doesn't mind the wait. Within a couple of weeks I had a
few hundred pounds bagged and stored. Over the years I kept a small
portion with me and re-slacked it from time to time, even letting it
freeze up here when staying in Peter's farm house. It would get a
little chilly in there sometimes. After moving to this cabin I slacked
it again and wedged it up and it threw like a dream. I think the aging
helped a lot. I think I still have some in storage down state and plan
to pick it up soon.
When I get set more set up I'm getting some red brick and building
another dewatering tray so I can get bagged clay and mix the old
fashioned way. Nothin like a little stoop labor to make this old man
feel healthy again!
Keep going!
Gary Navarre
Navarre Pottery
Norway, Michigan
Hank Murrow on sat 24 jul 04
On Jul 24, 2004, at 4:07 PM, steve harrison wrote:
> Hi Ben,
> I worked with Harry and May Davis at Crewenna in New Zealand.
> The vacuum filter press worked very well, however The Davis's didn't
> make all their clay this way however, most of it was dried on an old
> fashioned drying bed on the ground during the hot dry months.
Dear Clay Dryer aficionadaos;
I use my solarium to dry polyester/canvas bags of slip. These produce
around 400# of plastic clay per frame in around a week in my solarium
in the winter.......faster in summer. You can pull handles right away
with this clay. Learned it from Harry.
Cheers, Hank in Eugene
> murrow.biz/hank
Hendrix, Taylor J. on sun 25 jul 04
Ben,=20
That sound essentially the same as Harry's idea. You merely have just
one half of one filter bag. I think you should try it and see how well
it works. The Davis press is something I want to try some day myself.
Taylor, in Waco=20
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ben Shelton
Sent: Friday, July 23, 2004 1:36 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: dewatering clay slip
I was reading Harry Davis's book and ran across the chapter on the
vacuum
operated filter press. ...
I had imagined a cloth lined frame of sorts, into which clay slurry
could
be poured. The vacuum applied to the underside and a trap or reservoir
for
the water to collect in.
...
steve harrison on sun 25 jul 04
>> I was reading Harry Davis's book and ran across the chapter on the
>> vacuum
>> operated filter press.
Hi Ben,
I worked with Harry and May Davis at Crewenna in New Zealand.
The vacuum filter press worked very well. It was very easy to build
because it didn't need to cope with high pressure. It was built out of
tin plate and a light wooden frame. It used the vac pump from the pug
which was from an old dairy.
The Davis's didn't make all there clay this way however, most of it was
dried on an old fashioned drying bed on the ground during the hot dry
months.
I was given an antique porcelain vacuum separator which I used to dry
out small samples of clay body in the early days. It was a large bowl
with colander holes in the bottom, sitting on a large bowl underneath.
These two have a ground flush surface which we sealed with a smear of
vaseline (petroleum jelly). There is a spigot towards the top of the
underneath bowl to connect the vacuum pump.
A sheet of cloth was placed in the bowl and the clay slip poured in.
The vac pump drew the water through into the collecting bowl underneath.
It worked well enough, but used electrical power where the sun did the
same job just as fast for nothing. It might be more useful over there
in the US where the weather is less suitable for air drying during the
winter.
I might still have some photos of the Harry's vacuum filter press
somewhere if you are interested.
Best wishes
Steve Harrison
Hot & Sticky Pty Ltd
5 Railway Pde
Balmoral Village
NSW 2571
Australia
http://ian.currie.to/sh/Steve_Harrisons_books.html
Ben Shelton on mon 26 jul 04
Of course I'd like to see the pics!!
How long did it take to dry out a batch of slip with the vacuum press?
Thanks, Ben
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