bad keys on terminals

My only experience of RTV is as the 'gasket replacement' stuff. It works well for that, but that grade would be far too soft to make a roller. The Devcon stuff is a 2-pack -- adter mixing it lasts for 30 minutes (according to the data sheet I've read) and cures fully in 24 hours. They also sell a mould release agent to coat the mould with, and a primer to coat things you do want it to stick to (in my application I do want it to stick to the spindle). They specifically mention 'transport rollers' as a possible application, My main concern is that I know I'll have problems the first few times. Maybe I'll misdesign the mould, or be unable to get the part out, or whatever. The roller in question is about 3" lon and 1/2" in diameter, a lot less than one kit's worth of stuff. And I simply can't afford a complete kit for every attempt. IO've read the book 'How to cast small metal and rubber parts' (or some similar title). The authors say that Devcon used to recomend mixing part-kits, but now recomend against it. But that it should still be OK. -tony