After receiving a lot of comments and emails about this not working on certain objects i wanted to add that not all metals will rust.
Will screws rust a roof.
Coordinate color of roofing screw with roof panel color.
Wash the roof with detergent and water and scrub off any mold that has grown with a scrub brush.
Galvanization is a process that coats with zinc.
Cut a piece of steel roofing mesh to size to cover the area.
If you catch the problem before the rust virus makes its way down to the roof itself you can just change out the screws.
Not all metals will rust.
Stainless steel screws are rust resistant throughout the entire screw not just on the surface.
However if the rust has compromised the roof you very likely would have to change out all the panels at the least everything that has been affected just because of one little spot.
Unfortunately most primers are not formulated to seal rust.
The stainless steel screw will absolutely be the best screw to resist rust.
If you attempt to paint over rust you will inevitably see a recurrence unless you pre treat the metal with primer.
If the screw is over tightened and stripped out the threads cannot build up any resistance to backout or pullout forces.
I believe it has to have iron in it in order to rust and if it s galvanized stainless steel or some other type of metal that doesn t corrode then this process won t work.
Instead of carbon steel screws use stainless steel or zinc aluminum cap screws.
This not only reveals all the rust it ensures that the repair materials you use adhere properly.
Look for and use fasteners with a strong v neck head to prevent product breakage while on the job site.
Variety and choice matter.
If the coating is breached or the substrate has moisture or treatments that attack and deteriorate the zinc coating rust will occur as soon as the coating breaks down.
Rust is a natural process that occurs when metal is exposed to air and moisture.
If your metal roof has large sections of rust it s inevitable that you ll have to repair a few holes and cracks.