Valerie Johnson on wed 10 jul 02
I recently made 2 plaster molds of human torsos (finally liquored up my
models enough so they couldn't complain). I now need advice on making the
clay forms. I would like to use a stoneware or porcelain slab that is pushed
into the molds, as opposed to using slip. Will this work? If so, any advice
on how thick the slabs should be? Any advice on firing the porcelain so it
won't slump? I will probably fire these in my wood kiln. Any other advice at
all? Thanks.
Valerie Johnson
Eads, TN (where, yes, we do have a government--today, at least)
Burns Christina on thu 11 jul 02
I use a terra blanc 05-06 slab. Works great on torso. I cover the mold
with plastic (for protection) and then grease it up with Vaseline (for easy
removal). The tricky part is timing when to turn it over to affix hanging
devises. Let me know if you need any thing else. I simply love the torso's
and my friends tell me they do also, but I haven't found a market for them.
Good Luck!
L. Christina Burns
Ottawa University
Student Development Office
1001 S Cedar, #2
Ottawa, KS 66067
burnsc@ottawa.edu
-----Original Message-----
From: Valerie Johnson [mailto:VWJohnsons@AOL.COM]
Sent: Wednesday, July 10, 2002 9:11 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: using plaster molds of human torsos
I recently made 2 plaster molds of human torsos (finally liquored up my
models enough so they couldn't complain). I now need advice on making the
clay forms. I would like to use a stoneware or porcelain slab that is
pushed
into the molds, as opposed to using slip. Will this work? If so, any
advice
on how thick the slabs should be? Any advice on firing the porcelain so it
won't slump? I will probably fire these in my wood kiln. Any other advice
at
all? Thanks.
Valerie Johnson
Eads, TN (where, yes, we do have a government--today, at least)
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Bruce Girrell on thu 11 jul 02
Christina Burns wrote:
> I cover the mold
> with plastic (for protection) and then grease it up with Vaseline
> (for easy removal).
I'm not following that. You put plastic _inside_ the mold??? Wouldn't that
ruin the detail and doesn't the plastic wrinkle?
>The tricky part is timing when to turn it over to affix hanging devises.
Couldn't the hanging devices be implanted while the clay is still in the
plaster mold?
Bruce Girrell
in northern Michigan preparing for the show season starting tomorrow. We
fired almost 50 pots on the 4th with the Blue Angels shredding the skies
overhead during their practice runs for their shows the 6th and 7th
(National Cherry Festival). I hadn't realized how important the sound of the
burners is until I couldn't hear them over the jet noise. Makes
concentrating on the work difficult, too. They took out a couple of store
windows this year.
I'm convinced that someone on the city council of Traverse City has some
photographs of a Navy Admiral doing interesting things with a goat or
something*. We get the Blue Angels every other year when there have to be
thousands of other towns that would like to have them for the 4th.
I always watch them, half in awe at the skill and power of these men and
their machines, half in horror at what they represent and what it must be
like to hear that same sound knowing that the next moment may be your last.
*Actually, I understand that the Blue Angels simply like Traverse City.
Convenient airport, excellent clear performance corridor, plenty of good
landmarks, nice town.
Snail Scott on thu 11 jul 02
At 10:10 PM 7/10/02 EDT, you wrote:
>I recently made 2 plaster molds of human torsos...I would like to use a
stoneware or porcelain slab that is pushed
>into the molds...how thick...? Any advice on firing the porcelain so it
>won't slump?
This will work just dandy!
Are you joining a back and front together to
form a full torso 'in-the-round', or just
doing front (or back) only?
If you are doing 'in-the-round', the form
will probably be decently self-supporting
and need minimal reinforcement. If you are
doing a front or back, that will need more.
I call it "Snail's Toilet-Paper-Roll Theory
of Structural Design". (pat. pending) ;)
Put an empty cardboard tube on its end. You
can balance bricks on it, and it may even
support a person's weight. Turn that same
tube to horizontal, and it will easily be
smashed flat. Cut it in half, and it loses
all structural integrity. This principle
applies to clay also, and even more with
porcelain.
When you make your press-molded parts, I
would use a slab about 3/8" thick. To some
extent the choice will depend on your clay,
though. If you need more than one slab to
cover the mold area, smooth the edge of the
first slab against the mold surface at a
low bevel. This will minimize the lines on
the front surface after removal, and make
them easier to repair. (Of course, you can
place the lines in an interesting manner
and leave them visible by choice.) Press
the clay firmly and work it thoroughly all
over, to replace the slab's 'memory' of
its previous configuration.
One-sided pieces:
For clays prone to slumping, place
reinforcing ribs of clay across the inner
surface. Vertical will be the most important
direction if they are intended to be fired
standing upright, to resist warping. (Think
Gothic buttresses.) If they will be placed
on their backs/edges for firing, use transverse
ribs instead, to prevent slumping. (Think
barrel vaults.) Make them 2" deep or so, and
as thick as the slab. Lute them well, with
good slab-joining technique, so the ribs don't
separate from the form during drying.
If there are no undercuts of significance,
you can leave the forms in the molds 'til
they are stiff leather-hard. If you want
to free up the molds for re-use sooner,
let the clay reach a manageable stiffness
and tip the forms out onto foam. Turn them
periodically so that both sides can dry
equally, and as sood as they're stiff
enough, set them in the orientation that
you intend for firing.
For two-sided pieces:
Reinforcing ribs may not be needed at all.
You may need to test to find out, though.
Using a few vertical ribs will do no harm,
and you might be able to reduce their size
or number as you learn the limits of your
clay.
If your two mold halves fit tightly to
one another, you can stand up the molds as
soon as the clay has stiffened to leather-
hard. Fit the halves together, and lute
them deeply across the joint. Add a flattened
coil, too, for strength. Then remove the mold
sections. Let the piece dry standing up and
fire it the same way.
If the two mold halves don't fit tightly,
let the clay set up to a stiffer, self-
supporting stage, then remove from the
molds and fit the pieces together. Good
luting and coil-reinforcement of the joint
will be more critical with this method,
and fiber clay will also be a useful aid.
Vertical ribs may be helpful to help
maintain the shape while fitting and luting,
since the mold will have been removed.
Note: this sort of work is what paperclay
is best at. Press-molding and slab-joining
can really be enhanced by a little fiber.
-Snail
Nita on fri 12 jul 02
I use a bit of cornstarch, dusted into plaster molds to keep them from
sticking - it burns away so it doesn't change the color of your clay body.
Nita
----- Original Message -----
From: "Burns Christina"
To:
Sent: Thursday, July 11, 2002 9:03 AM
Subject: Re: using plaster molds of human torsos
> I use a terra blanc 05-06 slab. Works great on torso. I cover the mold
> with plastic (for protection) and then grease it up with Vaseline (for
easy
> removal). The tricky part is timing when to turn it over to affix hanging
> devises. Let me know if you need any thing else. I simply love the
torso's
> and my friends tell me they do also, but I haven't found a market for
them.
> Good Luck!
>
> L. Christina Burns
> Ottawa University
> Student Development Office
> 1001 S Cedar, #2
> Ottawa, KS 66067
> burnsc@ottawa.edu
>
>
> -----Original Message-----
> From: Valerie Johnson [mailto:VWJohnsons@AOL.COM]
> Sent: Wednesday, July 10, 2002 9:11 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: using plaster molds of human torsos
>
> I recently made 2 plaster molds of human torsos (finally liquored up my
> models enough so they couldn't complain). I now need advice on making the
> clay forms. I would like to use a stoneware or porcelain slab that is
> pushed
> into the molds, as opposed to using slip. Will this work? If so, any
> advice
> on how thick the slabs should be? Any advice on firing the porcelain so
it
> won't slump? I will probably fire these in my wood kiln. Any other advice
> at
> all? Thanks.
>
> Valerie Johnson
> Eads, TN (where, yes, we do have a government--today, at least)
>
>
____________________________________________________________________________
> __
> 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.
>
>
____________________________________________________________________________
__
> 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.
>
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