[Eliot Ness]

Richard,

The RTV might work for the molds, but it might be too soft, I haven't worked with gasket maker in a few years. The newest idea I have run across is making the shells on a 3D printer. Below is the work of someone else, not myself:

   
   
   
   
   

I believe he made his on a resin printer. I printed some off with plain old PLA filament, but for heat resistance PETG or maybe ABS would probably be best. I have some STL files if you're interested. The third picture is an enlargement I made in TinkerCad.