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pressmold advice

updated fri 6 apr 01

 

Marie Gibbons on sun 1 apr 01


Does anyone have any tricks in using latex or silicone molds for press
molding.
I am starting a new installation piece, that will have 7 babies... I made a
silicone mold (so as to have good detailing and be able to peel the mold back
off the piece instead of having to pull the clay out of the mold) Did my
first trial run, and the problems I am running into (which in some sense i
like, but would like to try a couple diff versions) is ....

since this is a very round mold.. pushing in a flat slab would produce
wrinkles/folds, so what i did was smooth on very thin layers of clay building
up to the thickness i wanted.

when i began to remove the clay... it was sticking in some areas of the mold,
so it tore off layers (which i kinda like, looks like it was down in the
ocean for a few decades and eroded and got all narly) I am thinking that
maybe something to aid in the release... murphys oil soap? or could i dust
it with a talc powder?

also, i did get some evidence of the way i laid the clay down in layers... is
there a better way to do a larger mold like this? it is an actual real life
size baby, 21" long, looks like the real thing, size and detailing.

I am using a lowfire raku clay... which i have been building in for 5 years.
.. . will fire the pieces to cone 04 and cold finish them..

thanks in advance to any advice that may be out there.

marie gibbons
www.oooladies.com

Nanci Bishof on sun 1 apr 01


Marie,

Did you make a plaster cradle for the mold? That allows you to use more
pressure to press the clay into the mold without tearing the mold. I think a
dryer claybody helps versus the wet out of the bag version of the same
claybody. You could do some controlled dying of your claybody to experiment.

nanci

Karen Shapiro on mon 2 apr 01


Hi Marie,

I've done a bit of press-molding into various
materials. WD40 always works, but will make things
slide around and it'll be tricky -- when I want to
avoid that, I'll use cornstarch which works great.
Instead of layering the way you are, you might try
using smaller pieces and smoothing the joining area as
you go. It's kind of a combination of slab/pinch
work. When you get used to the technique, it's quite
efficient and goes really fast.
Hope this helps,
Karen in Gualala

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Rick Monteverde on wed 4 apr 01


Kathy -

>I've found that rolling a tennis ball or a racketball in little circles works
>well to press clay into round molds.

Great idea!

Also good between your back and a wall for working out muscle stress. :)

- Rick Monteverde
Honolulu, HI

(Kathy Umemoto) on wed 4 apr 01


Marie,
I've found that rolling a tennis ball or a racketball in little circles works
well to press clay into round molds. Any folds roll out - seams too, if you
don't want them. Terrific texture pick-up on the other side too.

Kathy