Painting Bumper

[mini zilo]

I have a 97-99 style bumper from my brothers car to go on my 96 eclipse. The bumper is still painted the factory black color of his gsx, so when i sand it, how do I know when ive reached the primer? What grit paper is best? thanks.

 

[LoWang]

When and if I had to take off all the paint to get all the way down, I would use 180. Other options are, if factory paint is good spray over it. I spray bumpers alot if you need any help hit me up

 

[TalonTsi31]

i have a 95 talon but i just put an eclipsee conversion on the front (hood,bumper,headlights,and z3 fenders).this is my project car and some of the paint is flaky from the guy i bought it froms crapy paint job. what would be the best method for striping down the car to its primer.so i can alighn every thing and then shoot it.
any help would be awsome thanks.