Post #460783 by squid on Wed, Jun 10, 2009 12:10 PM

On 2009-06-10 10:38, MadDogMike wrote:
PDrake, that sculpt is lookin' awesome!

While we have the experts in this thread, maybe someone can help me understand about silicone masters and such. Do you make a silicon master only when you plan to make several molds? Like a commercial run of several hundred? If you plan to make only one mold for less than 50 pulls, you just make your plaster mold from your plasticine original, right?

Let me know if I'm hijacking here Perry and I'll shut up. :)

A rubber master (silicone or urethane) can be used to make just one mold if you want. And just to clarify, a rubber master is a duplicate of your original model, not a mold.
It's good for multiple molds.
Especially if your original model has some slight undercuts that you think might cause problems when pulling out your clay casting.

Otherwise you can make a plaster mold directly from your plasticine original. Just give it a clear coat first. Those oils leach into the plaster and inhibit the clay slip from drying.