Do i sand my bumper or do i just paint right over it??

 

The guy at the body shop supply place told me to sand it smooth, and try to either keep the original paint on there, or to only take it down to the original primer if I could help it. He said the pieces are treated with all kind of sealants and whatnot at the factory that I really don't want to remove if I can help it.

If you know your paint isn't horrible, I'd just scuff it up good. My paint was rattle canned at one point, so I went the chemical stripper route.

Mathius

 

Yeah, the bumpers on our cars are trickey to prep and paint. You want to use very high grit sand paper so you don;t pit or swirl the plastic. You need some bond-aid and some flex paint to do the bumper right. Some bumber clear coat would help alot as well. Any auto store will have all the stuff you need to do plastic and bumbers.

 

you guys shoulve posted this before I sanded my bumper with 80 grit!!! Even though I spent 4 hours trying to fix what i had done, the swirls and scratches still show throw the paintjob. Ill have to buy a new bumper cover later on.

 

thanks, the paint on my car is fair, what is that bando stuff your talking about and how do i use it??

 

bondo is a paste that is used for most body work. I would let a pro do it if youve never done that before.

 

Don't leave any of the crap that GM called paint on your bumper, I just sanded my front bumper down with fine grit and painted. Then 5 minutes after I pulled the cover out of the booth, the original paint underneath my shiny new paint cracked... with flex agent in the paint, which was still tacky btw...

 

Well, depending on what year model your 3rd gen is, I would say the factory paint job is of excellent quality. I have heard of some peeling issues with some certain year model cars painted in Cali. in the late 80's. Maybe thats your case? Although I doubt it would affect the paint that quickly, it sounds like you have a chemically incompatible combo in your paint.

*** knows I am not an expert, just trying to learn more about painting... Seeing as how I have a full set of completely stripped bumpers and ground F/X to paint soon, I want to learn all I can.

What I have at this point is a plastic primer that must be sprayed with a thin coat, then painted over with standard 2K primer. Of course this application is if the bumpers or gfx have been sanded down to bare plastic.

Now, as far as sanding and swirl marks go, there is simply no way to get rid of sanding/swirl marks when you go heavy grit (say 60, 80) unless you build the surface with 2K and wet-sand. I would prefer to remove any crap surface and GOUGE the substrate and wet sand later on then paint over any prior existing finish. Granted, this is alot of work and more then needed in most applications. If you are painting one single surface this is probably just a waste of time. Thats what sealers are designed for!

RSRAGTOP.. Did you use a sealer???

 

D M N - No no, not Bondo...Bond-aid. Bond-aid is an adhearant that should use whenever painting plastic. It helps the paint adhere to the generally slippry surface of the plastic. I've used it numerous time on the IROC and have been very happy with it.

 

when painting plastics use an adhesion promoter. if you have cracks in your old paint sand them all out it may even go into the plastic , in which case they need to be fixed. then a good coat of 2k primer is all you need before some paint. check the primers manufacturers instructions some primers require a flex additive when aplying them to plastics. make sure you get the surface perfectly smooth as youll spend more money on primer filling in scratches than with a filler