Both very good points, thank you! As you can probably tell, I’ve used air tools, but never really looked at the finer points. I’m lucky enough to have a very nice neighbour who, amongst other things, runs a company that works with industrial compressors and creates test rigs. He said similar to the above.
So yup, new safety valve ordered, and I’m going to start off with the tank reg pressure set very low, then slowly build up, and ensure its empty when not in use (and regularly drained down)
I’ve got an in line regulator/oiler on the way as well
I’m also going to try and get hold of a USB boroscope to check inside the tank before using, as that’s a lot of stored energy in there!