After make about 15 copies, something strange started to happen: the resin started to "react" with silicon rubber and started to atack and stick...
This was a good quality silicon and had to be strong - with polyester resin I can make more than 50 copies without problem but with Axon Fast Cast F-18 the mold is destroyed and useless after only 15... but unfortunatelly this is the only urethane resin brand available here...
I had to remake all molds
Now I'm testing a stronger silicon and reserching a way to protect from "resin atack"...
... and my failed parts "collection" is growing...