# Plaster Mold



## Front Yard Fright (Dec 23, 2005)

I've got a face made out of plaster I'd like to make a copy of out of latex. If I were to make a plaster cast of it, would it pop out? Or would it bond the two together? Could I use some sort of releasing agent to make sure that doesn't happen?

I've never dealt with the stuff before so I'm open for any thoughts or suggestions.
:jol:.


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## scream1973 (Dec 23, 2007)

I would think you could put like foil over the face to create a physical barrier between the 2


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## Front Yard Fright (Dec 23, 2005)

Yeah but if I were to do that I would lose the detail of the face.
It's a sculpture of a human face I'd like to replicate.


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## RoxyBlue (Oct 6, 2008)

FYF, you might send a PM to Scourge. He's one of the people here with a whole lot of experience casting and might be able to give you a quick answer on whether a release agent of some kind would work.


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## scourge999 (May 4, 2008)

I wouldn’t mold a rigid cast with another rigid medium. The possibility for mechanical lock is too great. If that were to occur you would lose both in a terrible hammer fight. Depending on your budget, I would get something cheap like mold builder latex or a bit more money, silicone to make a mold of the plaster face then, you could back that up with plaster or ultracal 30 mother-mold. If you go the fancy silicone route, you could cast many faces in almost anything, foam, resin, plaster, poo, mache and it requires no release. Hope that helps a bit.


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## Allen H (Feb 13, 2010)

Since you said you want latex pulls, here is the easiest way to do that. Make a silicone or latex mold of the face.
Make a mother mold over that with plaster bandages.
Remove face from mold.
Heat up a pourable clay and pour the into the mold.
remove once clay has cooled
you now have a clay replica of the plaster face
then make a plaster mold of the clay face
remove the clay and then fill with latex.
wait 15 to 20 min and pour out excess
allow to dry, then pull your latex face from the mold!


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## Sickie Ickie (Jun 20, 2006)

Unless you want to do only one or three casts (or so) in latex. If that's the case, you can treat it like a human face and use quick setting alginate for the mold with a plaster bandage mother mold on the outside. 

In 5-10 minutes remove it, then just flood/paint the mold with latex and wait for the latex to dry to remove it.

The alginate shrinks as it dries and becomes brittle and unusable, but it will dry slowly over the next couple days, so you should get some nice latex castings with excellent detail.


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## Front Yard Fright (Dec 23, 2005)

Thanks for all the excellent thoughts and opinions guys...
What if I were to paint the face itself and then poured plaster over it?
It would be fine... wouldn't it?


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## Sickie Ickie (Jun 20, 2006)

IF the plaster is too porous, you run the risk of the latex becoming very stubborn to remove if painting it with that.

You can try a spot (maybe on the back?) and see if it removes okay.

If it does, remember you'll have to put on multiple coats to make it thick enough and keep it from tearing when you peel it off.


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## Front Yard Fright (Dec 23, 2005)

I ended up just jumping in and giving it a couple coats of acrylic medium to create a barrier between the two then poured a cast over it. Waited for that to dry, then poured plaster over the top... currently waiting for that to set up right now... hopefully it works!
.


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## Dr Morbius (Sep 21, 2004)

Front Yard Fright said:


> I ended up just jumping in and giving it a couple coats of acrylic medium to create a barrier between the two then poured a cast over it. Waited for that to dry, then poured plaster over the top... currently waiting for that to set up right now... hopefully it works!
> .


If there are NO undercuts you should be OK. That includes curves. Let us know how it goes, I have my doubts that you will succeed, but I hope you prove me wrong!


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## Sickie Ickie (Jun 20, 2006)

Nostrils for undercuts can be killers. And chin.


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## scourge999 (May 4, 2008)

Ya gotta watch out for that mechanical lock man! I hope it works. Under cuts like the sides of the nostrils are undercuts and could prevent it from releasing! I got my fingers crossed for ya. But I too have my doubts.


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## scourge999 (May 4, 2008)

Jinx Sickie, I think we posted at the same time, LOL


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## Front Yard Fright (Dec 23, 2005)

Hahaha Well I was able to remove the face fairly easily... However, it looked like I made my plaster too thick and it didn't catch much detail at all... It was REALLY rough looking.
I'm out of plaster right now, but I'll cast it again and post my results later!
:jol:.


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## Sickie Ickie (Jun 20, 2006)

Totally cool that you proved us wrong, FYF! Good luck!


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## Dr Morbius (Sep 21, 2004)

Yea, if it released this time, it might release with a thinner mix. Let us know.


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## Allen H (Feb 13, 2010)

Can you post a pic? a few of us on here could visually identify undercuts and let you know if it would be all right.
I dont think the alginate will work because latex will not really dry in it. Maybe very very thin layers will, but the alginate will shrink if its dry enough to allow latex to dry in it.


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## Sickie Ickie (Jun 20, 2006)

Allen H said:


> Can you post a pic? a few of us on here could visually identify undercuts and let you know if it would be all right.
> I dont think the alginate will work because latex will not really dry in it. Maybe very very thin layers will, but the alginate will shrink if its dry enough to allow latex to dry in it.


Yepper. Latex dries in it. I found out by experimentation when I did one of my live casts. :googly: Humidity plays a factor though.

Made 2 latex faces from that one alginate mold.

Remember that alginate uses water and evaporation to dry. Latex uses ammonia.


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## Front Yard Fright (Dec 23, 2005)

I will post a picture later tonight. It's a flat backed sculpture of a man's face about 4 inches thick. Right now I've got it mounted to some foam board to prevent plaster from getting underneath it when I pour it.

As far as undercuts, I ended up filling in the nostrils and some of the mouth to prevent anything from sticking.

And as it turns out, Walmart doesn't sell plaster anymore? Boo!
.


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## Front Yard Fright (Dec 23, 2005)

Got more plaster the other day. Hopefully going to work more on this this week. I'll keep you posted!


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## TheOneAndOnlyKelly (May 7, 2009)

What was your results? Sorry for raising the dead on this post, but I'm trying something similar atm...


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