Yup, loads of progress now, I have pulled the shells away from the RTV and pulled the master out of the mold, as expected, some of the cardboard parts of the master didn't survive very well and I will have to fix it if I ever need to make a master mold again. That's not for today, so I've cleaned up the RTV but it is a little on the thin side, I will certainly be needing that thickening agent.
I also made a few mistakes with the fiberglass jacket, as the rubber is thin, it tends to fold away from the fiberglass shell when I am trying to fit it into it, so, next time, not only will I put bolts to keep the two halves together, I will place screws in at the base to ensure the mold is placed correctly.
I had to spend a good 20 minutes getting it right so I could place the screws in.
But enough of me, here's the master mold
I will have to make a copy from this mold and work on it I am afraid, as I found a bubble one of the key slots. I may try fill this in with PVA glue though, I haven't decided yet, but I want to make sure that the final cast will be perfect, so I need to have a master that won't fall apart on me.
I will be really careful when I give the process a go tomorrow to ensure that I get a perfect cast!
Edit:
I ended up using a latex based glue to fill in the two air bubbles, though it isn't the best solution, it will be good enough for the one cast.
I will also do my cold cast experiments with this mold too.