Rust stain??

Of course my phone camera absolutely refuses to focus on it particularly well, but I've got a weird stain on my access cab door and a few other places. I think it's some sort of iron/rust contamination really deep into the paint.

It's low down on the truck, on the parts that have the anti-chip undercoat;



I know I've also got a little bit of rail dust contamination as you can see here and there, but this streak of what looks like a rust stain really sticks out like a sore thumb.

Already washed and tried a buffing compound, it wouldn't budge. Would something like Iron-X take care of this??

Any other suggestions?

 

I guess the first obvious question would be "Do you see rust on the inside near the same area?" Also, have you noticed that spot grow at all?

Judging by the shape of it, I wonder if a chemical or something splashed from the tire and wasn't removed for a while, and the residue is etched in the paint. My wife's car has the remains of 2 bird droppings etched in her paint because they weren't washed off for 2 months.

My last suggestion is, if you have an endoscope, there's a small access hole on the end of the door panel. I would check to see if you have any rust on the other side of that panel. If you don't have one, they're less than $20 on Amazon and are really handy tools to have.

Just my $0.02, I'm sure others with more knowledge will chime in.

 

Try clay bar.

 

The truck is basically new, has about 3,000 miles on it since I bought it in May. It's not rust from the inside.

The chemical splash is what I'm thinking. I got the car muddy as hell on a Sunday and didn't get to thoroughly wash till Wednesday, but that's not a particularly long time...

I live in Pennsylvania, and to go offroading I went into Amish country where they use horse drawn buggies a lot, my best guess (and it is just a wild guess at this point) is that it was a glob of bearing grease with iron deposits in it from a buggy wheel. Splashed up and started a rust stain under the mud... maybe?

Forensic examination of my mud... Enhance!

Will do. At least, before I try buying Iron-X or some other chemical I've been recommended.

 

that may be filiform corrosion

 

Vehicles are prone to small isolated rust spots from road debris. This is known as "iron fallout" and is most commonly caused by iron particles becoming embedded in the clear coat and rusting. A cheap way to remove the spots is by using a light-medium clay bar to remove the particles, however this runs the risk of scratching and marring the paint surface. The best solution is to use an iron dissolving solvent such as Car Pro IronX or even Sonax Wheel Effects Plus. Hope this helps!