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Hi. Im trying to work out the best way to release plasster from intricate acrylic  pieces. 

There is fine text and i need to make 10 moulds of a board with 50 pieces on it.

I currently use soft soap with mixed results.

I was letting plaster harden for over 24 hrs but read on here i should release just after its gone through the heat process and cooled.

Any advice would be appreciated. 

20181104_121114.jpg

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There is something we use in dentistry called plaster separator.  It's a sodium alginate mixture and works very well.  It's designed to separate plaster moulds from the acrylic we press into them.  Worth a shot.  Also called liquid foil.

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It can be difficult to get the plaster to release if the original has straight sides. 

I've had occasions where I have had to carve the plaster out of the master and start again.  I want to make a mould from a bowl, but whatever I try, the plaster just sticks.  Next time I'm going to try putting a balloon in the bowl, and pour the plaster into the balloon.  I'm hoping the balloon will follow the shape better than say, clingfilm.

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Chilly, I also had a lot of trouble with straight sided rigid forms.  Things got much easier when I used Vasaline or shea butter, thick rather sticky mediums, for release agents in those straight sided forms.  I rubbed it on like I was greasing a baking dish, all around.  Pieces came right out as soon as they cooled., with very clean smooth side walls.

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Thx. The problem is for where the lettering is. If i use something like vaseline it will just fill up spaces of letters. I guess i could do a 2 prong method of vas on sides and soft soap on the top.

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I just wiped it on with a soft tight grain sponge once and do it well. I used green soap for years until I bought a Gallon of pure lube.Which iS made for this application. I also use it on rolling clay onto plastic forms so it releases .I'm sure down under you have a similar product.

Really any water based lubricant will work well and not affect the plaster. Some oil based lubes can plug up plaster wickering water abilities. That is plug the plaster pores sort of speak so it does not work as well in slip applications .

People use all types of crazy stuff from motor oil to shoe polish and get various results-Heck someone here thought a meat grinder was going to be a great clay extruder. Turns out it was not.

I would stick to water based lubricants working with plaster unless you want the plaster sealed.Green soap was from the 50-60s.

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