Backing/supporting vacuum table molds (halo reach)

[monoman527911]

Hey! Me and my team have been building molds from a base of pepekura for my thermoforming machine...
My question is since our molds are positive, what would be a cost effective way to back the mold for the table?

Plaster? Or some kind of clay?


Thanks

-Steve

 

[Tigerblood]

plaster or even concrete if you have to.