debby schwartz on tue 10 jul 07
After attending a mold making course over 3 years ago, I finally purchased
my first mold and the slip to pour into it.
I have the straps to bind the two halves together.
Do I need to prepare the mold in any way so that I can successfully remove
the finished piece when it is dry?
Was there a powder or soap to dust on the inside or was that specifically
for making a mold around an item?
Any tips for success would be appreciated!
Thanks,
Debby
Fredrick Paget on thu 12 jul 07
It is very easy.
Just pour the well mixed slip into the mold and keep your eye on it.
The level may sink as the slip looses water into the mold and
depending on the design you may need to top it up. With good slip
and a new mold it should be ready to dump in a short time - maybe 15
minutes . You have to judge that by watching the thickness of the
clay on the mold.
Then dump it out. That is, empty the mold and set it on a grill or
something upside down to drain. when it stops dripping turn it over
and wait an hour or so. This time is variable.
The ware will start to shrink away from the mold and can be removed.
If it sticks bump the mold with the heel of your hand or a rubber
mallet to loosen it up .
Carefully ease it out of the mold onto a ware board.
Now is the time that extra pieces are assembled onto the piece .
Also cut off the sprues at this stage.
Some mold sets have multiple pieces that are assembled to make the
finished piece. Extra parts are stuck on using slip as glue when the
pieces are fresh out of the molds.
Now you let it dry and you have greenware that needs fettling and sponging etc.
For some strange reason this whole process is not PC and is frowned
on by some ceramic artists. They can be ignored. This is just another
way to make stuff and if you make the molds yourself it is creative.
--
Twin Dragon Studio
Mill Valley, CA, USA
marci Boskie's Mama =^..^= on fri 13 jul 07
> debby schwartz wrote:
>
>After attending a mold making course over 3 years ago, I finally purchased
>my first mold and the slip to pour into it.
>I have the straps to bind the two halves together.
>Do I need to prepare the mold in any way so that I can successfully remove
>the finished piece when it is dry?
>Was there a powder or soap to dust on the inside or was that specifically
>for making a mold around an item?
>Any tips for success would be appreciated!
Here is actually a good little tutorial with pictures. It is on pouring
miniature doll molds but the information is good for any kind of slip casting.
http://www.cynthiahoweminiatures.com/castingmolds.htm
The inside of a mold shouldnt need a releasing agent. The soap youre
talking about is used to coat the item youre making a mold of so that
it releases... You dont use it when pouring a mold..
If the mold is really dry ( If it is very hot where you live or you
havent used the mold in a while) , you can lightly mist the inside with
water which keeps the dry mold from grabbing the slip at that spot and
making lines or marks in the finished piece... Also, if you have a
mold that has small or intricate parts that are difficult to release,
you can light dust the mold with a little talc powder before you pour
it..
One important note: Make sure the mold is tightly banded before you
start to pour.. You should be able to put your fingers in the
pour hole and not be able to pull the mold apart. A large mold full of
slip exerts a lot of pressure on the seams and you want to make sure
the banding is tight enough or youll be cleaning slip off of
everything. ( You , the floor, the table..)
As far as how thick the slip should be , how soon to pour out the
excess slip, when to unmold it......this is something that youll
learn by trial and error... I read everything I could get my hands
on before I started and still, the first several things I poured were
disasters! ( I poured an egg mold that bore a strange resemblance to a
Cadbury Chocolate egg... Squidgy on the outside and filled with
a soft " creamy" slip filling LOL ! ...I couldnt get the mold to
empty ...
So, expect a learning curve LOL !
Marci Blattenberger Boskie's Mama =^..^=
http://www.marciblattenberger.com
marci@ppio.com
Porcelain Painters International Online http://www.ppio.com
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Cindy reed on fri 13 jul 07
For slip casting you do not need to do anything to prepare the mold. Just
pour in your slip and add slip as the water starts getting absorbed in to
the plaster. When your cast is thick enough then you pour out the excess
slip. If you are doing press molds you would probably want to put a release
agent, i.e.. Corn starch.
Hope this helps,
Cindy
Greenville, NC
On 7/10/07 6:49 PM, "debby schwartz" wrote:
> After attending a mold making course over 3 years ago, I finally purchased
> my first mold and the slip to pour into it.
> I have the straps to bind the two halves together.
> Do I need to prepare the mold in any way so that I can successfully remove
> the finished piece when it is dry?
> Was there a powder or soap to dust on the inside or was that specifically
> for making a mold around an item?
> Any tips for success would be appreciated!
> Thanks,
> Debby
>
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debby schwartz on tue 17 jul 07
Thanks to everyone who responded about the mold making process.
The internet instructions were also ver helpful.
I poured the slip and my first mold came out beautifully.
However, with the second one- a piece of plaster broke off the inside of the
design.
I guess I didn't let it dry out enough.
Any ideas on plaster repair?
Deb
marci Boskie's Mama =^..^= on thu 19 jul 07
> debby schwartz said:
>
>Any ideas on plaster repair?
>Deb
There are commercially available mold repairing solutions
( clear stuff in a bottle ) and I believe you can also use Apt
II ...but plain old Elmer's Glue will do the trick.. Just take care
not to get any on the inside surface of the mold.. ( and yes, I
know that Elmer's is water based.. and the molds soak up water..
but that doesnt seem to affect the repairs..)
Marci Blattenberger Boskie's Mama =^..^=
http://www.marciblattenberger.com
marci@ppio.com
Porcelain Painters International Online http://www.ppio.com
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