I am wondering how I should go about filling/repairing very small rust holes (width of a screw). I took off the running boards/fenders on my truck and I just want to prevent rust holes from forming. The paint around the holes is completely fine and rust has not spread... yet. The hole is all the way through the body panels and I do not want to sand down the paint around it if I do not need to. Is there any filler I could put in these holes? Also, the holes are not visible unless you are looking under the truck. Please let me know if you have any suggestions for how I should go about doing this repair. Thank you!
What I would recommend doing is cutting a Way all the rust and if the holes are still small enough fill them with weld if they’re bigger you can get some scrap metal and weld it in if you get rid of the rust it will help prevent more rust if you do that after you can go to a hardware store it in the spray paint section And get some rust prevention spray
Once you start seeing holes, that's it. The rust is now in advanced stage. The panels have rusted from the inside, and the metal is weakened and thin to the point where it's now starting to poke through. What you see is only the paint holding surface together. The holes will get bigger, and new ones will appear, and there's nothing you can do. Such is life.
It's a cliche, but a true one - rust never sleeps. You can bet it's worse than it appears on the surface. The only real cure is to cut out the corroded metal and weld in good replacement metal. Anything else is just a temporary band-aid. You can't otherwise stop the rust but to slow it down you could spray something like Fluid Film into the panels.
