Editing Rust, pitted

[[Image:blank.jpg|right|thumb|350px|A classic example of pitted rust. If you have this image, or can take the necessary photograph, please [[Special:Upload|upload it to the wiki]].]] Pitted rust is a common problem when dealing with body panels. It's also a little ==What causes pitted rust== Rust pitting is caused by a localized lack of oxygen in metal. This causes a small area to become anodic (it readily gives up electrons), while the slightly more oxygen-rich surrounding area becomes cathodic (readily accepts electrons), accelerating the local formation of rust. For more details, see [[Rust#What is rust?|What is rust?]]. Pitted rust can be more insidious than surface rust. While the pits may comprise only a small volume of a piece of metal, the widespread perforation can compromise the overall structure of the metal. ==How to fix pitted rust== The "best" way to fix pitted rust on body panels is to generously cut out the rusted area, and weld in new metal. This is not always a viable option for all people, in all situations. A more common solution is to remove the rust, mechanically and/or chemically, clean the panel thoroughly, fill the pits with a purpose-specific finish product, and coat with [[epoxy primer]]. ===Removing the rust in the pits=== First, all visible rust must be removed ====Mechanical removal of pitted rust==== *A spot blaster is useful for this, with silica as the medium (confirm, and get list of other acceptable media). *Also, the following can be used: metal brush, grinding wheel, die grinder, a wire wheel on a drill. (what 3M discs are recommended for this?) ====Chemical removal of pitted rust==== ==Additional resources== *[http://www.materialsengineer.com/G-Pitting-Corrosion.htm Pitting Corrosion] -- MaterialsEngineer.com *[http://www.corrosion-doctors.org/Forms-pitting/Pitting.htm Pitting corrosion] -- Corrosion-Doctors.org *[http://en.wikipedia.org/wiki/Pitting_corrosion Pitting corrosion] -- Wikipedia *[http://www.corrosion-doctors.org/Forms-pitting/shapes.htm Corrosion pit shapes] -- Corrosion-Doctors.org

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