Tried out this new stuff from Formcard for getting mouldings off existing lugs to make repairs, put it in very hot water as you see, left it cool for a few seconds moulded it to lug and took an impression, would recommend that you block off any holes first with wax or some other removable substance , I didn't and found it awkward to get off but it took the pattern very well, will try melting some ABS in some ABS cement and pouring it in to make a lug

That mold would be good with Plastex, which is a similar idea to what you are trying.

Good thinking that Dave, I spent too much time sniffing acetone I forgot about that