Ceramics group?

I know this is the wrong place, but I am hoping someone here can direct
me to the right place.

I want to learn how to make molds and pour clay to make ceramic
decorations.

Any help appreciated.

"Noname" wrote in message
. com...

I know this is the wrong place, but I am hoping someone here can
direct
me to the right place.

I want to learn how to make molds and pour clay to make ceramic
decorations.

Any help appreciated.



Where in the world do you live?

"annemarie" wrote in message
...

"Noname" wrote in message
. com...

I know this is the wrong place, but I am hoping someone here can
direct
me to the right place.

I want to learn how to make molds and pour clay to make ceramic
decorations.

Any help appreciated.



Where in the world do you live?

Near Tampa Bay, Florida, USA

On Wed, 28 Jan 2004 21:07:40 GMT, "Noname" wrote:


I know this is the wrong place, but I am hoping someone here can direct
me to the right place.

I want to learn how to make molds and pour clay to make ceramic
decorations.

Any help appreciated.



This is probably as good a place as any. It sounds like
you are interested in "slip casting". That will allow you
to make hollow vessels. If you don't need the decorations
to be hollow, you might be able to make them by
"press molding". Tell us more about exactly what you want
to make.

The molds in either case are typically made from plaster.
You can use plain old plaster of Paris, or pottery plaster
(which is better, and cheaper in big bags). You need to make
the molds such that there is no undercut area; you should
be able to move the clay straight out from the mold without
it hanging up on anything. That often requires multi-part
molds, but when you are just starting out you would be
better off to find something simpler.

If you have a simple piece with a flat back, yo may be
able to stick it down in a flat-bottomed plastic container
using a bit of plasticine modelling clay, then paint it
with liquid soap (as a parting agent) and cover with
wet plaster. After it is set up, pull out the original.
Let the plaster mold dry for a few days or more, then
press a wad of pottery clay into the cavity. It should release
fairly easily, since the plaster will suck moisture away
from the contact surface and cause the clay to shrink
slightly. Then dry and proceed as for normal pottery,
(bisque fire, paint with glaze, glaze fire).





Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

"Bob Masta" wrote :

This is probably as good a place as any. It sounds like
you are interested in "slip casting".

Thank you, just learning the phrase "slip casting" was enough to make my
searches more fruitfull.

What I want to make are things like the Christmas houses you see in
stores. So they would be partly hollow and partly solid (the base). I think
slip casting is the answer.

The part I really want to learn is the making of the molds, but of
course I will need to be good at working with them when they are done.

Thank you, just learning the phrase "slip casting" was enough to make
my
searches more fruitfull.

What I want to make are things like the Christmas houses you see in
stores. So they would be partly hollow and partly solid (the base). I
think
slip casting is the answer.

The part I really want to learn is the making of the molds, but of
course I will need to be good at working with them when they are done.


Might I also suggest a good book:
"Clay, A Studio Handbook" by Vince Pitelka
Chapter 4 deals exclusively with plaster working, mold making, and
slip casting, and is comprehensive enough to be of good use to you.
Hope that helps,
Wayne Seidl

"Bob Masta" wrote :

It should release
fairly easily, since the plaster will suck moisture away
from the contact surface and cause the clay to shrink
slightly.

Just a side question, can I depend on the amount of shrinkage? I want my
peices to be exactly 6 inches across so I need to know the shrinkage when I
(re) make my mold.

On Thu, 29 Jan 2004 19:18:57 GMT, "Noname" wrote:


"Bob Masta" wrote :

This is probably as good a place as any. It sounds like
you are interested in "slip casting".

Thank you, just learning the phrase "slip casting" was enough to make my
searches more fruitfull.

What I want to make are things like the Christmas houses you see in
stores. So they would be partly hollow and partly solid (the base). I think
slip casting is the answer.

The part I really want to learn is the making of the molds, but of
course I will need to be good at working with them when they are done.


You might also check into local businesses. In SE Michigan, at least,
there are (were) a lot of hobby ceramics shops that appear to have
fallen on hard times. These shops typically buy the molds and just
cast their own wares, which they sell as greenware or bisque. There
are also shops where people can walk in off the street, select a piece
of bisque, paint it with supplied glazes, and come back and get it
after it is fired.

These businesses might be your competitors if that is your goal,
but otherwise they might have some practical tips. And if you
approach one of those that is having hard times, you might be
able to buy all your supplies in one go, at cheap prices. I've
seen a number of Going-out-of-business sales around here.







Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

.....want my
pieces to be exactly 6 inches across so I need to know the shrinkage when
I
(re) make my mold.

In which case you need to ask your slip supplier about the shrinkage of a
particular product, and know to which temperature you will fire it. As a
reference, I use porcelain slip, fire it to ^6 or higher (1200 deg. cel.)
and it shrinks almost 14%
If you make your model for mold out of clay, it will also start shrinking as
soon as it starts drying
Also, molds for houses will need to be made from several parts so you can
get the cast out without braking it. You will need to measure ratio of
plaster to water for each part so that they are the same(otherwise the
absorption of water from slip will be uneven and cause problems)
hope it helps,
Andrea

"Noname" wrote in message
. com...

"Bob Masta" wrote :

It should release
fairly easily, since the plaster will suck moisture away
from the contact surface and cause the clay to shrink
slightly.

Just a side question, can I depend on the amount of shrinkage? I want
my
peices to be exactly 6 inches across so I need to know the shrinkage when
I
(re) make my mold.

shrinkage will depend on the clay/slip you are using as they differ in
rate.allow anything from a couple of percent up to about 14%. it
really is trial and error when you want a specific result size.