John Rodgers on wed 27 feb 08
Jesse,
You are right. I don't like pumps and hoses and tanks. They do clog.
they do have to be cleaned constantly. They are a royal pita. BUT - if I
was running a serious production operation, Well, that is a whole
'nother matter.In fact, hoses, pumps, return lines, slip heaters, etc,
etc, would be a necessity.under those circumstances. But for the studio
potter/artist - it is too much. I like the K.I.S.S Principle - keep it
simple, stupid! It really works.
I don't know where the stigma on casting comes from. Is it just a
perception? Slip casting has been around for an incredibly long time. Is
it just ignorance? Assuming "oh, there is no skill in that,piece. It
came from a mold!". Well, perhaps the work did come from a mold. But so
what? When it comes to thrown work versus molded works, so far as their
value as art pieces are concerned, there is no difference. In fact, if
trying to arrive at some esoteric description l about the art value of
the work, I would lean towards the slipcast, mold made work. From my
perspective, with thrown work you can't get there from here.Some wheel
work is absolutely awesome, but I am always blown away by the incredible
porcelain slip casting work I see out in the world. Keep in mind that
slip porcelain cast in a mold is a clay as well as is white stoneware
thrown on a wheel. Process is a bit different between the two, but not
that much. A form must be created by the clay, the form dried as
greenware, the greenware cleaned fired to bisque, the bisque glazed and
fired again to make a completed piece of work.The only real difference
is in how to get the form created. Some create the form directly on the
wheel with the hands. Others create a model, by which they make a mold,
into which they cast sli8p to get a form. From that point on, the work
is essentially the same.Most people done even have a clue as to the
complexities of creating a form from a drawing on a piece of paper
through the molding process to a finely finished work of art
Edward Marshal Boehm is one of my favorite artist. His slip molded
porcelain work was incredible. When Nixon went to China, a pair of mute
swans was pelleted from Boehms studio to be a gift from America to the
People of China.The gift was received with an extraordinary degree of
gratitude and enthusiasm
Though Boem has been dead since the '70's. his work lives on. To see
some amazing work, check out Ebay.
Boehm was enamored of birds, especially sugarbirds, and he kept an
aviary of them. he produced a porcelain piece called simply
"Sugarbirds" To give you a bit of an insight into the amount of skill,
works and energy required, he created an porcelain art piece of the
Sugar Birds The mold set weighed in over 6000 lbs, and had 600 parts to
it. Not long ago, one of his pieces - Ivory Billed Woodpeckers on a
stumpo - sold for like $150,000 - and it was broken. The detail in this
work is incredible.
So, nobody has any right to have airs about their own work.
Just my point of view.
John Rodgers
Chelsea, AL
Jesse Hull at Wiseman Ceramics wrote:
> Thank you John,
> This all valuable information.
> I understand the process of casting & mold maintenance. I had the privilege
> of learning the basics of mold making and casting from the experienced folks
> at Campbell Pottery when Bill had me and some others out.
> ...But the equipment end of it had me a bit confused. Your perspective helps
> a lot.
> Question: You don't like pumps, flow nozzles, etc then-- You're saying that
> they were constantly clogging?
>
> I really enjoy the work I do on the potter's wheel, but being able to cast
> my glaze tests for now will really help... later(when my hands and back tire
> too easily), I'll have the experience in casting to continue with clay and
> glaze if I choose.
>
> Not to open a can of worms on that subject, but I do wonder about the stigma
> associated with casting.
> Thrown & hand-built work can look pretty bad if the goals aren't set high
> enough, and I've seen some cast work that blows my mind.
> Most everything is just a means to an end. I think it's all in the hands of
> the maker, really...
>
> ~jesse.
> ____________________
>
> RE: Slip-casting equipment -John Rodgers
>
> Jesse,
>
> My experience has taught me that simplicity is the best way to go. I
> have worked with the tables with tanks an the tanks with pumps for the
> pouring and all of that. I have even worked in a big plant where we had
> 500 gallon vats of slip. We has small open vats - 50 to 100 gallons -
> with side mounted pumps and hoses. We would fill the smaller vats from
> the 500 gallon tanks and then wheel them over to the casting tables
> where we would pump the slip into the molds. When the molds were full,
> we then parked the rolling vats under the drains in the casting table.
> Then, when the molds were drained the slip would drain back into the
> rolling vats under the casting tables, then the rolling vats were rolled
> over to the big 500 gallon tanks, and the slip was pumped back into the
> larger tank to be continually mixed, and adjusted for density as
> viscosity for next days casting. It was a miserable process, because
> slip is constantly thickening, drying, plugging the pumps or hoses. It
> was a PITA, quite frankly. We even had a multi-point connector at the
> bottom of the big500 gallon tank and a pump whereby we could pump from
> the big tank to dasting operations across the room by means of hoses and
> a big diaphragm pump. But it was still a big PITA, given all the
> cleanup, and the hose and pump manintenance that was necessary.
>
> If found over time, that for small operations, a free standing , plain
> mixing tank with mixer attached, and a simple casting table with no
> tanks, no other attachments, just a drain hole in either the center or
> at one end, makes for the easiest operation.
>
> 1) Mix your slip in the mixing tank, drain through a screen into a
> bucket for casting purposes.
> 2) Before casting, put a 5 gallon bucket under the drain hole in the
> table, and have a spare by it's side so you can do a quick swap if one
> gets full.
> 3) Take the slip bucket to the molds on the table, and pour. ( I use
> Rubber Maid 2-1/2 gallon buckets becasue they have a keen pouring
> spout. which makes it easy to control the slip stream.
>
> That takes care of the casting side of matters.
>
> 1) To drain, when ready, simply turn the molds over very slowly,
> draining while truning, so that no suction develops to collapse the
> piece inside, and when well drained, park the now empty molds upside
> down and allow it to finish draining. .
> 2) Empty the buckets of drained slip back into the mixing tank.
> 3) Open the molds, and do the trimming on the table, allowing the
> trimming and mold cleanup to fall into the table,
> 4) Remove and store the molds to dry, using lots of circulating air. The
> moving air drys them much faster. Moving warm air drys much faster than
> moving cold air - BUT, no matter what, the air must be moving.
> 5) Set aside the new greenware.
> 6.) Scrape and clean the support rods of the table, allowing the
> cleanings to fall through the table bars into the table trough.
> 7) Clean the table of all clay scraps.
> 8) Through all dry scraps back into the mixing tank.
>
> End of process.
>
> For something more than operations from a 5 gallon bucket, this is about
> as simple as it gets. I have worked with all kinds of home made stuff,
> but for my money, the purchase of the free standing mixer and the very
> plain jane casting table is the only way to go. You actually an do a
> great deal with this, yet it won't break the bank.
>
> If mixing a new batch of slip from dry mix, I aways mix then wait 24
> hours. I always add Barium Carb and Soda Ash.
> Just before casting, I weigh a batch of slip to determine density,
> adding water if necessary. Then when density is correct, then I test the
> viscosity, adding sodium silicate if necessary. I use a viscometer
> devise I got from New Mexico Clay for $4.95. Beats the heck out of that
> thing Laguna tries to sell to everyone for $25.00
>
> If working with slip to which scraps from yesterdays casting was made, I
> always check density, and viscosity, first thing, before pouring. All
> the numbers will change over time as casting is done.
>
> Hope this helps.
>
> John
>
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>
Jesse Hull at Wiseman Ceramics on wed 27 feb 08
Thank you John,
This all valuable information.
I understand the process of casting & mold maintenance. I had the privilege
of learning the basics of mold making and casting from the experienced folks
at Campbell Pottery when Bill had me and some others out.
...But the equipment end of it had me a bit confused. Your perspective helps
a lot.
Question: You don't like pumps, flow nozzles, etc then-- You're saying that
they were constantly clogging?
I really enjoy the work I do on the potter's wheel, but being able to cast
my glaze tests for now will really help... later(when my hands and back tire
too easily), I'll have the experience in casting to continue with clay and
glaze if I choose.
Not to open a can of worms on that subject, but I do wonder about the stigma
associated with casting.
Thrown & hand-built work can look pretty bad if the goals aren't set high
enough, and I've seen some cast work that blows my mind.
Most everything is just a means to an end. I think it's all in the hands of
the maker, really...
~jesse.
____________________
RE: Slip-casting equipment -John Rodgers
Jesse,
My experience has taught me that simplicity is the best way to go. I
have worked with the tables with tanks an the tanks with pumps for the
pouring and all of that. I have even worked in a big plant where we had
500 gallon vats of slip. We has small open vats - 50 to 100 gallons -
with side mounted pumps and hoses. We would fill the smaller vats from
the 500 gallon tanks and then wheel them over to the casting tables
where we would pump the slip into the molds. When the molds were full,
we then parked the rolling vats under the drains in the casting table.
Then, when the molds were drained the slip would drain back into the
rolling vats under the casting tables, then the rolling vats were rolled
over to the big 500 gallon tanks, and the slip was pumped back into the
larger tank to be continually mixed, and adjusted for density as
viscosity for next days casting. It was a miserable process, because
slip is constantly thickening, drying, plugging the pumps or hoses. It
was a PITA, quite frankly. We even had a multi-point connector at the
bottom of the big500 gallon tank and a pump whereby we could pump from
the big tank to dasting operations across the room by means of hoses and
a big diaphragm pump. But it was still a big PITA, given all the
cleanup, and the hose and pump manintenance that was necessary.
If found over time, that for small operations, a free standing , plain
mixing tank with mixer attached, and a simple casting table with no
tanks, no other attachments, just a drain hole in either the center or
at one end, makes for the easiest operation.
1) Mix your slip in the mixing tank, drain through a screen into a
bucket for casting purposes.
2) Before casting, put a 5 gallon bucket under the drain hole in the
table, and have a spare by it's side so you can do a quick swap if one
gets full.
3) Take the slip bucket to the molds on the table, and pour. ( I use
Rubber Maid 2-1/2 gallon buckets becasue they have a keen pouring
spout. which makes it easy to control the slip stream.
That takes care of the casting side of matters.
1) To drain, when ready, simply turn the molds over very slowly,
draining while truning, so that no suction develops to collapse the
piece inside, and when well drained, park the now empty molds upside
down and allow it to finish draining. .
2) Empty the buckets of drained slip back into the mixing tank.
3) Open the molds, and do the trimming on the table, allowing the
trimming and mold cleanup to fall into the table,
4) Remove and store the molds to dry, using lots of circulating air. The
moving air drys them much faster. Moving warm air drys much faster than
moving cold air - BUT, no matter what, the air must be moving.
5) Set aside the new greenware.
6.) Scrape and clean the support rods of the table, allowing the
cleanings to fall through the table bars into the table trough.
7) Clean the table of all clay scraps.
8) Through all dry scraps back into the mixing tank.
End of process.
For something more than operations from a 5 gallon bucket, this is about
as simple as it gets. I have worked with all kinds of home made stuff,
but for my money, the purchase of the free standing mixer and the very
plain jane casting table is the only way to go. You actually an do a
great deal with this, yet it won't break the bank.
If mixing a new batch of slip from dry mix, I aways mix then wait 24
hours. I always add Barium Carb and Soda Ash.
Just before casting, I weigh a batch of slip to determine density,
adding water if necessary. Then when density is correct, then I test the
viscosity, adding sodium silicate if necessary. I use a viscometer
devise I got from New Mexico Clay for $4.95. Beats the heck out of that
thing Laguna tries to sell to everyone for $25.00
If working with slip to which scraps from yesterdays casting was made, I
always check density, and viscosity, first thing, before pouring. All
the numbers will change over time as casting is done.
Hope this helps.
John
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