Hi Colin, I use Axon F16 too. With regards colours as it happens I've been experimenting today adding graphite powder to the mix to tone down the colour as its a chassis part and also to see if it made the resin a bit stronger. Below are the colours, the one with the motor attached is the resin on its own and the other two have varying amounts of graphite powder added....
The graphite doesn't affect the finish only the colour. Graphite powder is cheap and easy to come by as its used for lubricating locks, you can get 50g puffer bottles which would be more than enough to last a lifetime for a couple of quid.

The graphite doesn't affect the finish only the colour. Graphite powder is cheap and easy to come by as its used for lubricating locks, you can get 50g puffer bottles which would be more than enough to last a lifetime for a couple of quid.