Hello together, I plan to repaint my rear bumper this coming winter. Painted eighteen years ago. Perfect for ten years. Then slowly some bubbles began to appear under the paint. Not overall. But a few spots. Now it's gotten so bad, that I will repaint the bumper. Not, that it's a big problem for me painting every ten to twenty years But I'm curious, what happened here. It's not above the exhaust tips. So I cannot suspect heat. Any ideas? Image Unavailable, Please Login Best from Germany and thanks in advance Martin
Have you popped open a bubble to see what is under it? Some things that cause bubbles are usually from prep not done right before painting. Is there rust under the bubbles or powdery substance or nothing?
Are US-bumpers steel? Then I forgot to mention, it's of course GRP. I suspect something outgassing. What still makes me wonder, why it didn't occur for ten years after painting and then suddenly occured. Best Regards Martin
I believe that US bumpers are steel which is why many replace them for the lighter plastic ones. I did and moved them in like the Euro cars. Of course it took ten years because of global warming. [emoji6]
Follow this procedure. Did it on my 308. Came out better than factory. https://www.mgexp.com/article/rb-repair.html
Thanks. But since flexibility of our bumpers is somehow limited, I think flexible paint is over the top. I will stick with my old procedure. Plastic primer, filler, basecoat and semi-matte clearcoat with a small amount of plasticizer. Meanwhile I have opened a bubble. They are probably caused by a adhesion problem between filler and basecoat. I will sand the filler more carefully next time. Best from Germany Martin
