It comes in two tubes, a resin and a hardener which is mixed in the same proportion for two or three minutes then leave it for a few minutes, as it will be fairly runny and doing this will make it easier to work with. It starts to go hard after about twenty five minutes and is best left for 24 hrs to fully harden. It will dry grey and can be drilled, filled, tapped, sanded and painted.
It's available from Amazon UK (an American product).
I'm sure there are other products too, but I hope that may help.