Thanks guys...Glad you like them..
Iron Art...
The casting I do is in urethane resin..I start out with a wood pattern and put as much detail into it that I want..Then I build a mould box to put the master in... allowing for expansion of the moulding rubber to come next...I mix RTV rubber with a hardner and put the mix in a vacuum chamber to get all the air bubbles out..I usually pour the rubber right over the pattern and then de-air it..It expands as the air leaves the mix, and that is why the over size box...once the air is re-introduced back into the vac chamber the rubber returns to it's original volume...
Let the rubber "kick off" or cure out...then remove the rubber off the master and you have a mould..
The urethane resin is a 2 part. equal parts A and B..It needs to be mixed completely for over a minute, or untill you sense heat building up...Pour it into the mould and it "kicks off" withn 5 minutes and you have a reproductoin of the original pattern..
The urethane is white when cured resembling ivory...I have made pistol grips before and they look good...The urethane should be used for decorative pieces only and it is no where as strong as metal where powered models are concerned....It works well for almost all static models though..
Here is a link to Smooth-on products for getting silicon rubber and casting resin and more
http://www.smooth-on.com/
I hope this helps..