No primer on rear bumper?

[edco]

Not sure where to put this so if this is in the wrong place my apologies..

My Huntington Green 06 X5 rear bumper (with PDC for when you get too close) got severely gauged by some a-hole who was too lazy to turn his/her steering wheel all the way to get out of the spot behind me.
Add to that my disregard for above referenced beeping from the PDC, and I put a nice deep gauge in it on both corners.

So a friend of my who works in a BMW dealership had one come in and the rear bumper (Alpine white) had the tiniest crease just below the PS tail light. So they replaced the bumper cover with one from the factory, and I got the one they took off.

Yesterday he was kind enough to do me a favor, put my X on a lift and change my scratched and gauged bumper for the like-new one.

Here's the question: When I spoke to a trusted Body Shop they advised that the bumpers DON'T get primed. They scruff them up a bit all around and then spray with the matching paint for my car.

Something about the bumpers being made of a plastic composite which would cause primer to flake underneath the paint even from a minor tap from a grocery store cart, not to mention the parallel parkers from hell.

I thought that bizarre - no primer on the bumper and thought I would ask here since my buddy's away for the weekend.

Thanks as always
ED

[diyanich]

I sprayed out a piece of paint when I washed my X for a first time,yeah 1750 PSI and flakes of paint fell off,I was so pissed.
I still have to get it repainted.
Like to me,I don't think that primer makes it flake....who knows,maybe they're right

[nsxttt]

From what I've seen, you do prime the bumper and also use flex additive for the paint.

[edco]

Well I stopped by my friends at Open Road and they concurred that there is no primer necessary on a repainted bumper. Here is what I learned. Remember my replaced bumper is Alpine While over Flex-Prime, so all that is needed is to rough up the paint to eliminate any shine, remove any wax, polish etc, and she's ready for painting. I hope to have it done this week so it'll definitely be ready for the CT Get-To-Gether.Also BMW bumper specific paint is "rubberized" for flexibility. The bumper cover is actually mounted into a system designed with horizontal shocks, and the sides are held in place via tracks on both sides, thereby giving it some movement horizontally.
See the part indicated as #4. It has the ability to "slide" inside a track, again adding to the flexibility.


Only time will tell...
Ed in NJ

[DoubleA]

When I re-paint a bumper I use PPG SXA 1044, it is a high build surfacer that you put before the base coat, this way the base coat wont peel-off.

https://buyat.ppg.com/refinishProduc...c-68079bd3d62d