B& D powdercoaters, Buckingham Drive Wangara. Good prices, has been recommended to me by others, fairly quick turnaround and also knows quite a few of the old vintage colours - like the difference between Tahitian Red and Flame Red etc - I use him all the time now.
Just around the corner next to the Police vehicles repair place on Gnangara drive I think it is is a good sandblaster but sorry cant remember his name and not there at the moment. If you are up that way he is very visible from the road in the industrial estate.
Hope that helps if you are North of the river.
regards
Rossco