I used this method for my Slave Leia resin and fibreglass parts as well as my Samara (Mass Effect 2) collar piece. I made a tutorial for the local costplayers in NZ over here:
http://cosplaynewzealand.forumotion...ique-f31/budget-molding-and-casting-t9028.htm
For me it really saved about 66% of molding costs as molding silicon here is very expensive. Even with caulking tubes at between $NZ13-20 a tube (about 500gm or just shy of 1lb) it worked out much cheaper.
Also when you use condensation cured silicon and use the soapy water method you have a heck of a lot of control over where the silicon goes.
As mentioned in my tutorial urethane resin really does make the silicon quite brittle/dry but epoxy seems to be fine. I did press bondo into some molds and it was ok so polyester resin will also be ok. It did make the molds stink. I mean really stink. The smell lasted for a very long time.
I made jackets of plaster to support the silicon and when it came to the complex curves of the Leia bikini top I mixed a paste of epoxy resin and fairing powder and painted that into the molds. Meanwhile I had some matting soaking in some more resin and when it reached the gelly stage I mixed some more fairing powder in and pressed that into the mold and then wrapped the whole thing around my mannequin (which was covered in glad wrap).
I used cooking oil spray as my mold release- worked very well on the plasticine but I should have used a bit more on the plastic parts and also something a bit more solid than liquid on a few metal parts.
I did find it worked best with the translucent stuff and really badly with some black roofing silicon. That just never really cured all the way through. Not sure if there was some reaction with the pigments in it or I just had a bad batch.
http://cosplaynewzealand.forumotion...ique-f31/budget-molding-and-casting-t9028.htm
For me it really saved about 66% of molding costs as molding silicon here is very expensive. Even with caulking tubes at between $NZ13-20 a tube (about 500gm or just shy of 1lb) it worked out much cheaper.
Also when you use condensation cured silicon and use the soapy water method you have a heck of a lot of control over where the silicon goes.
As mentioned in my tutorial urethane resin really does make the silicon quite brittle/dry but epoxy seems to be fine. I did press bondo into some molds and it was ok so polyester resin will also be ok. It did make the molds stink. I mean really stink. The smell lasted for a very long time.
I made jackets of plaster to support the silicon and when it came to the complex curves of the Leia bikini top I mixed a paste of epoxy resin and fairing powder and painted that into the molds. Meanwhile I had some matting soaking in some more resin and when it reached the gelly stage I mixed some more fairing powder in and pressed that into the mold and then wrapped the whole thing around my mannequin (which was covered in glad wrap).
I used cooking oil spray as my mold release- worked very well on the plasticine but I should have used a bit more on the plastic parts and also something a bit more solid than liquid on a few metal parts.
I did find it worked best with the translucent stuff and really badly with some black roofing silicon. That just never really cured all the way through. Not sure if there was some reaction with the pigments in it or I just had a bad batch.
