I've made a face sculpture in clay. Now I want to make a hard cast of that sculpture in polyurethane resin. The thickness of casting should be 2-3 mm. Can anyone please describe me the process of cast making? And I don't know what type and quality of resin to be purchased for making hard casting, any suggestion regarding this will be appreciated.
explains it pretty good...
you need to make a silicone mold off the sculpt;
once you have the mold then you can do what is called roto-casting (sometimes also referred to as sluch casting) where you mix your resin and pour into the mold, then manipulate the mold to coat the surface of the mold to make a hollow casting; I have used SMOOTH-CAST ROTO for this process - works like a charm.
There are roto-casting machines for this purpose but they can range in price from $ 500 - $ 25,000 (US); you can get good results by hand with smaller molds, but the process becomes unweildly with larger molds
you can avoid this process by designing your mold to have a plug inside which will control the hollowness of your casting w/out having to manipulate your molds.
I'm considering making a 7mm diameter hollow ball by roto-casting. Can anyone comment on how thin a surface can be made by this method? My goal is to create a rigid ball that is as light weight as possible. Would 0.5mm be possible? Less? Would Smooth-Cast Roto be an appropriate?
Any thoughts on this would be greatly appreciated.
You will have no problems with the hollow aspect of it if you spray on the PU. You will use less PU too. The 2 part PU will give you around 5 minutes to get it out of the spray gun, before it starts setting.
Apply Silicone rubber on it with brush, then pour the Pu in that, that you will get the face cast.
If you are in India then you can buy from us. we can teach you then how to cast it. its simple.