I just scored a "new" bumper from a guy in my town who was selling it for $100. He bought it brand new a few years ago for $300 because he had some front end damage but decided on using the bumper off a parts car he also bought which matched his original paint (red). He tried returning the new bumper but they wanted a 25% restocking fee so he decided to keep it instead.

My bumper (black) has a chunk of paint missing and some minor cracks. This bumper is a primed part (black) which, when new, is supposed to be painted over to match the car color. This part looks to be 14 years old though, judging by the date written on the inside.

My question is: Can I paint or clear coat it (maybe after some light sanding) and what, if any, would the repercussions be? Another option, could I just mount it on my car as is or would the primer chip after some time?

I'm not looking for a factory finish on the bumper but id like to know if I can just throw it on my car as is without risk of the primer being damaged under regular driving compared to a painted bumper.

Thoughts/opinions?

 

If you are painting it yourself, don't get too fine about your techniques or your expectations.

If the bumper is already primed, I would clean the bejeezus out of it with rubbing alcohol.

Then sand lightly with 320 grit.

Paint two or three light coats of color of your choice. Wet-sand with 1500 or 2000 grit in between coats, and clean with rubbing alcohol if you feel really compelled to do everything humanly possible in your driveway.

Two coats of clearcoat with wet-sanding final coat with 2500 grit.

That should keep you busy, and should produce a result that will look very decent.

 

Red scotchbrite pad, a wax/grease remover and then paint away. Some new paints can be laid down right on that factory primer even without scuffing the surface. never believed it but I know one company says its ok and will warranty it if there is a problem
That is a general idea but call a paint supply place for instructions for your brand of paint

 

whatever you do, don't install it without painting it. chances are that factory primer isn't going to stand up to UV very well.

 

If you do decide to paint it, clean and scuff with a gray scotchbrite or lightly with a red one. If the primer is thick you may have to use 600 grit instead or even lower. Make sure you seal it before basing. Factory primer is usually very thin and is not meant to be based over without sealing. There is a chance that its old enough to have "shipping primer" on it and isn't meant to be painted over at all. Ive heard that occasionally new parts used to come with that and it would need to be sanded off, though in 6 years of painting ive never seen it and I doubt you'd have to worry about it.

 

Chances are it's a very thin and probably cheap coat of primer. Sand it with 320 and then 400. It will probably be sanded mostly off by then. I'm a big BIG proponent of using the same brand everything for a paint job so go and buy your 2K primer and shoot a coat or two and then wet sand to 400 if it's a light color or 600 if it's a dark or metallic color. Don't color sand unless you get runs or sags. Color coats are thin and are only meant to be sprayed as thin as possible. Any manufacturer will tell you spray to coverage and then one more. 3 light coats is plenty of color. For clear if you have a high solids you can get away with two coats. For a low solids it may take you four coats of clear. Air on the liberal side since its much easier to sand a run then to respray a spot where you sanded or polished through.

 

You will need a good flexible filler 3M makes a good 2K filler and you will need to sand where the cracks are all the way back down to the rubber then clean with a plastic cleaner then apply 2 light coats of bulldog adhesive promoter