I have learned another "skill" thanks to cyclekarts, and thanks to Steve Cole.
For the next/current build I wanted to copy a radiator badge. I took a silicon mould from the real one, and then "slush cat" a copy with the recommended Fast Cast resin packed with brass powder. I'm delighted with the outcome, now looking for other things to use it for.
No, I'm not showing the outcome till a bit later in the build.

I'd be very interested to see how the "slush cast" bit is done. How do you take the mould without affecting the original etc?

In the dim and distant past I slush cast parts for a model car suspension, as the originals were prone to breaking. Slush casting is pouring a mix of resin chopped glass and a filler (brass in this case) into a mould. It can also be used for reinforcing sections of mouldings that are too thin to use mat, or to form fillets in corners, without the filler in this case.

For making silicone moulds I use Lego type building blocks, Ideally the silicone should be vacuum degassed, but if poured slowly from height, so as to make a thin strand, that does a pretty good job of removing air bubbles.