Plaster/silica thickness??

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gthomson
Posts: 23
Joined: Tue Jan 20, 2004 4:53 pm
Location: Ontario, Canada

Plaster/silica thickness??

Post by gthomson »

Hi all,

What's a reasonable thickness for a plaster/silica mold? 10" plates and shallow bowls, that sort of thing.

TIA,

Glenn
Tony Serviente
Posts: 328
Joined: Thu May 29, 2003 11:48 am
Location: Ithaca,NY
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Post by Tony Serviente »

I usually aim for a pretty even 3/4". Less than that and I lose them in handling. I also try and keep the wall thickness as uniform as I can, to prevent uneven heating which the mold and glass does not like. I have not had a problem going thicker, it just wastes the plaster.
gthomson
Posts: 23
Joined: Tue Jan 20, 2004 4:53 pm
Location: Ontario, Canada

Post by gthomson »

Thanks, Tony. I've made up some patterns to these numbers.

I've gone through the archive and settled on a simple 50/50 hydrocal white/230 flint blend. I'me assuming the water requirement is based on the plaster content and that the flint just goes along for the ride, right?

Cheers,

Glenn
charlie holden
Posts: 260
Joined: Thu Mar 13, 2003 8:26 pm
Location: Atlanta

Post by charlie holden »

rdguy wrote:Thanks, Tony. I've made up some patterns to these numbers.

I've gone through the archive and settled on a simple 50/50 hydrocal white/230 flint blend. I'me assuming the water requirement is based on the plaster content and that the flint just goes along for the ride, right?

Cheers,

Glenn
The flint, (or silica), still has to get wet. I use a 1.75 to 1 ratio of premixed dry ingrediants to water by weight when I'm making strong, open faced molds. For softer plugs I go down to 1.65 to 1, dry to water.

ch
gthomson
Posts: 23
Joined: Tue Jan 20, 2004 4:53 pm
Location: Ontario, Canada

Post by gthomson »

OK, thanks, Charlie

Glenn
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