Priscilla Wilson and/or Janice Lymburner on thu 6 jul 00
I'm trying to figure out a way to pump the slip out of my molds but am =
not ready/able to invest in one of those machines yet. I tried a =
portable oil pump without success. Has anybody tried a shop-vac? I'm =
thinking of trying it with PVC pipe and/or some kind of smooth, flexible =
hose instead of the corrugated hose. Any better/additional ideas would =
be appreciated!
In case anyone else is slipcasting on a shoestring, I've hit on a pretty =
good and easy way to store and dispense the slip - an old Igloo cooler =
with spout at the bottom for draining off liquid! =20
Thanks-
Priscilla Wilson
Donald Burroughs on fri 7 jul 00
Dear Priscilla
I used a shop vac when I first started slip casting in art
school. It is effective, but only for limited castings, I would not suggest
this method if you are planning production runs because you would probably
burn out the motor rather quickly because the viscosity of the slip will put
tremendous strain on the bushings in the vac motor while sucking up large
amounts of slip. The wet vac though is effective at eliminating any pooling
of casting slip. It also is a handy process for casting with multi coloured
slips in the same mould where layers of colour are desired in a piece- you
pour slip carefully to a certain level with out splashing the upper wall of
the mould- let set to form a wall- then vac the excess out- let this layer
firm up, but not to the stage of release then pour the next coloured slip et
al.
Donald Burroughs
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of amy parker
Sent: July 7, 2000 1:17 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: CHEAP ways to pump casting slip
Priscilla - I recently acquired a lot of slip-casting stuff from a friend
whose mother did this for 35 years...one of the items was a "slip sink",
which is almost identical to the cooler, but it is a lightweight fiberglass
thing with a spigot so that you can shut it off. In order to drain the
molds, you just upend them over the slip sink. There is supposed to be a
slatted shelf on top of this but it has gotten lost over the years - I am
using one of those extra-large cooling racks for cakes & cookies over it. I
never heard of pumping the slip back out of the molds, but I haven't done
slipcasting in 30 years, so maybe times have changed! I know you can pump it
in, but I thought you had to turn them over & let them drain until the slip
stopped running out, rather than trying to suck it dry. It is tough with
the larger molds my kids want one each of!!! Giant piggy banks! (They can
put on the glaze themselves! - summer projects.)
I like the idea of the cooler because it has a lid - I turned my back on the
slip sink, which is outside, to cook dinner and came back to find a tiny
bird mired up in it! We put it in the bird bath, literally, and it flopped
around and rinsed off. Unfortunately, it did not survive. Poor Little
Bird!!! I now have an improvised cover.
I am in the Atlanta area and have access to hundreds of slip molds, most in
very good to excellent condition, selling from $5 to $10 each, if you are
interested.
Amy
At 11:56 PM 7/6/00 -0400, you wrote:
>I'm trying to figure out a way to pump the slip out of my molds but am not
ready/able to invest in one of those machines yet. I tried a portable oil
pump without success. Has anybody tried a shop-vac? I'm thinking of trying
it with PVC pipe and/or some kind of smooth, flexible hose instead of the
corrugated hose. Any better/additional ideas would be appreciated!
>
>In case anyone else is slipcasting on a shoestring, I've hit on a pretty
good and easy way to store and dispense the slip - an old Igloo cooler with
spout at the bottom for draining off liquid!
>
>Thanks-
>Priscilla Wilson
amy parker Lithonia, GA
amyp@sd-software.com
____________________________________________________________________________
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John Rodgers on fri 7 jul 00
Pumping slip OUT of a mold may be done somewhere, but I have never seen it.
Even very large molds are usually set up do that they drain, either by turning them over or by having specific drain openings in the molds. One of the problem areas you can get into with drainging is maintaining a clay wall of uniform thickness in the greenware. This requires a fairly steady, smooth, fairly rapid filling, and then at the appropriate time, a smooth,
fairly rapid emptying of the mold. If not done correctly uneven wall thickness occurs with resultant warping and cracking.
Some years ago, I saw a film of the operation of a toilet fixture manufacturing plant in the northeast USA, and the bowls and tanks were cast in huge molds. The molds were suspended on an overhead conveyer system. At the appropriate station porcelain slip was pumped into the molds from an overhead delivery system. As the molds moved along the system, there was
sufficient travel time to allow the slip to set up an appropriately thick clay shell, and at the appropriate station, with mechanical assistance, the molds were turned up, draining the slip from the molds. The toilet tank was cast as a single piece, but the toilet bowl was cast in a right and left half. After sufficient setting time the two halves were removed
from their respective molds, an then slip applied to the edges, and the halves joined together. When all work was completed, they were fired in a huge train kiln that looked to be a city block long. It was enormous, and the kiln cars were about like boxcars, with toilet bowls stacked high. The film was an education to me about industrial applications of clay work
and mold use. I relate this story to you hoping it may help with ideas about how to deal with your big molds.
You might want to contact Jeff Lawrence, a member of this list, and speak to his expertise in this matter. He runs a production facility in northern New Mexico and uses large molds for which draining is a problem, and on some has worked out some unique methods of dealing with the problem.
Good luck.
John Rodgers
Birmingham, AL
Priscilla Wilson and/or Janice Lymburner wrote:
> I'm trying to figure out a way to pump the slip out of my molds but am not ready/able to invest in one of those machines yet. I tried a portable oil pump without success. Has anybody tried a shop-vac? I'm thinking of trying it with PVC pipe and/or some kind of smooth, flexible hose instead of the corrugated hose. Any better/additional ideas would be appreciated!
>
> In case anyone else is slipcasting on a shoestring, I've hit on a pretty good and easy way to store and dispense the slip - an old Igloo cooler with spout at the bottom for draining off liquid!
>
> Thanks-
> Priscilla Wilson
>
> ______________________________________________________________________________
> 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.
amy parker on fri 7 jul 00
Priscilla - I recently acquired a lot of slip-casting stuff from a friend
whose mother did this for 35 years...one of the items was a "slip sink",
which is almost identical to the cooler, but it is a lightweight fiberglass
thing with a spigot so that you can shut it off. In order to drain the
molds, you just upend them over the slip sink. There is supposed to be a
slatted shelf on top of this but it has gotten lost over the years - I am
using one of those extra-large cooling racks for cakes & cookies over it. I
never heard of pumping the slip back out of the molds, but I haven't done
slipcasting in 30 years, so maybe times have changed! I know you can pump it
in, but I thought you had to turn them over & let them drain until the slip
stopped running out, rather than trying to suck it dry. It is tough with
the larger molds my kids want one each of!!! Giant piggy banks! (They can
put on the glaze themselves! - summer projects.)
I like the idea of the cooler because it has a lid - I turned my back on the
slip sink, which is outside, to cook dinner and came back to find a tiny
bird mired up in it! We put it in the bird bath, literally, and it flopped
around and rinsed off. Unfortunately, it did not survive. Poor Little
Bird!!! I now have an improvised cover.
I am in the Atlanta area and have access to hundreds of slip molds, most in
very good to excellent condition, selling from $5 to $10 each, if you are
interested.
Amy
At 11:56 PM 7/6/00 -0400, you wrote:
>I'm trying to figure out a way to pump the slip out of my molds but am not
ready/able to invest in one of those machines yet. I tried a portable oil
pump without success. Has anybody tried a shop-vac? I'm thinking of trying
it with PVC pipe and/or some kind of smooth, flexible hose instead of the
corrugated hose. Any better/additional ideas would be appreciated!
>
>In case anyone else is slipcasting on a shoestring, I've hit on a pretty
good and easy way to store and dispense the slip - an old Igloo cooler with
spout at the bottom for draining off liquid!
>
>Thanks-
>Priscilla Wilson
amy parker Lithonia, GA
amyp@sd-software.com
Jonathan Kaplan on sat 8 jul 00
We pump slip both in and out of our molds, as well as pump slip all over
the casting area.
We also sometimes use buckets.
Lehman Manufacturing in Kentland Indiana is the numero uno source for slip
equipment. You will find that they have a large selection of stock items
and they are also custom designers and manufacturers. In fact, Chuck
Lehman's dad invented the first slip pump using a rotor and a stator. Call
Chuck and I am sure he can help you.
Regarding pumping slip....
The best way to pump slip is with a pump that has as few moving parts as
possible that come into contact with the slip. No matter how find that slip
is, it is abrasive and will wear out moving parts that it contacts. You
need to use an air operated diaphragm pump.
Some brands are Wilden, Warren Rupp. We have 2 small Wilden pumps and they
could suck the shorts off of you. They move slip perfectly. They can pump
in and suck out. The slip moves in one direction, so it is a matter of
where you put the hoses. A shop vac will easily be destroyed using it as a
slip pump.
We design some molds that utilize a bottom drain device. This is simply a
removeable plaster or rubber plug on the end of a dowel that has been cast
as part of the mold. When the mold is ready to be dumped, you just pull up
the dowel and the slip drains out the bottom of the mold. The hole is then
patched with slip when the piece is removed.
This is a very useful technique for big molds. Consider the weight of the
mold, then the weight of the mold with slip in it. Pumping out or using a
bottom drain is far more desireable than moving big heavy molds that can
also be damaged in the process.
Designing bottom drain molds is not that difficult, it just requires some
early thinking when designing the mold and then a few more steps when
making the mold.
You can contact me off the list if I can be of any further help.
Good luck
Jonathan
Jonathan Kaplan, president
Ceramic Design Group
PO Box 775112
Steamboat Springs CO 80477
voice and fax 970 879-9139
jonathan@csn,net
http://www.sni.net/ceramicdesigin
Plant Location:
1280 13th Street Unit 13
Steamboat Springs CO 80487
(please use this address for all deliveries via UPS, comman carrier, FEd
Ex, etc.)
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