I am looking to paint some sand blasted suspension parts that are supposed to look natural steal. If i use detail gray in spray cans do i need a primer under it? I have some two part epoxy but i would be doing such small jobs that i don’t want to have to mix some up each time i paint. Same goes for the black parts i am thinking of using the Satin Extreme Chassis Black in spray cans again over sandblasted parts. Do i need the Chassis Black primer or not?