Do you plan on weathering the blaster? Or keep it a nice new look?
For non-weathering, follow the instructions on the can, I used Rustoleum for my custom saber and it works great. 2 coats of primer (let dry for 48 hours). 2-3 coats of paint (set for 24 hours), 2-3 coats of clear coat (set for 24 hours).
For weathering you can do many different things. You can try to use the salt method, hairspray method, dry brushing, or actually use a dremmel to nick and scratch (I prefer not to use this method).
There are tons of cool modelling tutorials on youtube that can be used for weathering props as well.
