Is this rust on my steel bumper?

Just noticed that my bumper has this stain. Is it rust? The bumper is powder coated so it would be weird that it rusted through? Unless it's from the inside out? Any suggestions on how to clean this up - short of taking the bumper off and recoating it. Thanks.

 

What have you used to try to clean it?

 

Rock chips.

Hit it with rust converter, and shoot some paint or bed liner on it.

 

I've tried the typical car wash cleaners. I also sprayed some rust remover spray on there. And scrubbed it. Nothing really helps, but I don't want to get too crazy with chemicals before coming on here and asking around.

 

If powder coat gets chipped, you will get rust.

 

Doesn’t look like rust to me. Looks like some chemical reacted to it or the powder coat was flawed or something was wrong with the process. I’d clean the entire bumper and paint it.

 

Doesn't look like typical “brownish‐orange” rust bleeding through.

Possibly mineral/salt residue, road grime, or even oxidation on the coating itself?

I'd try a strong all purpose cleaner and a brush if it doesn't come off then lightly sand and use a touch‐up or rust‐converter primer. I had a little rust spot pop up on my powder coated backcountry adventure mods steel bumper from where the powder coat got scratched. I hit it with a wire wheel or flap disk I can't remember and some Rust-Oleum and it's held up well and stopped from spreading.

 

From the pic it looks like the Mill Scale under the powder coat. Powder coat has been chipped off via winter salt getting into cracks or rocks hitting it. Bumpers need maintenance. Today that is not rust but it will be sooner or later and will make the rest of the powder coat flake off.

Clean it
Scuff it
HHit it with acetone or degreaser, paint it with a good primer. Powder coat is a form of plastic so Krylon does well. They have paint formulated to bond to plastics.
Then hit it with a Truck Bed Coating. Should last you a good 5 to 7 years depending on use and abuse.

https://www.krylon.com/en/products/rust-preventive
https://www.krylon.com/en/products/automotive
https://www.krylon.com/en/products/specialty/bonding-primer-with-fusion-technology

https://www.rustoleum.com/product-c...oating/professional-grade-truck-bed-liner-kit

 

Do I need to do the whole bumper or do you think it'll match well enough to hit just those panels?

 

Your bumper. You do you.
If it were me, I'd do the whole thing.

But you can start small and just do those panels. Stop as soon as you are happy.

 

I'll hit the panels just to last me through the year. End of the year I plan to take it off and get it re powder coated. Just wanted to make sure if it was rust, that it wouldn't keep spreading until then. Thanks.

 

That sounds like an excellent plan. I think I would have done the same if you are getting it re-coated.