how to expand or enlarge rtv

[JAJIM]

Hello,I am a die cutter and sculpture ,normally I tool dies for belt buckles ,awards ect.on occasion I need to shrink or enlarge a recent project,I know how to get rtv to shrink,but don't know how to get rtv to expand or make larger,can someone help,what is the magical chemical used to get rtv to expand larger from the original cast model

 

[trooper]

how do you get it to shrink?

 

[jedimaster]

This smooth on stuff is pretty good. You have to monitor it though or else it will get to big. You place the silicon in a bath of this real nasty stuff and it expands over a period of time. So after say 6 hours it's 20% larger. Once it reaches the approx size you need just pull it out and pour your resin. If you need itbigger just put it back in the chem bath.

How do I enlarge or shrink a casting? | Mold Making and Casting Materials Rubber, Plastic, Lifecasting, and More

 

[JAJIM]

how do you get it to shrink?

how you get it to shrink is,add naptha or xyleneto the liquid rtv mix let it cure,as it cures the naptha will evaporate,when rtv has cured the rtv mold will be smaller,to determine how much of a percentage of shrinking depends on how much naptha is added,example,to do a 50% reduction mix 50/50,hope this helps

 

[trooper]

cool to know
years ago when megatron was making one of my custome rings, he used a silicone product that shrank on its own, it worked pretty cool, but did distort the detail.