Rust Never Sleeps

Treatments
Rust treatments, generally, start with elbow grease, removing the bubbles and pock marks with grinders, wire brushes, sandpaper or sand blasting, and taking the infected area down to bare metal. The more deep-seated the rust, the more aggressive the tools.


There are also rust paints available that seal or encapsulate the rust. These products are highly flammable and include toxic chemicals that require professional application. Acids can also dissolve rust, leaving a thin oxide coating on the surface. Like the paints, acid rust removal necessitates special breathing equipment. For high-end restorations, metal panels (or the whole car) can be submerged in a hot bath of caustic soda, stripping all the paint down to the metal. The panel is then treated in a tank of alkaline solution and the rust removed electrolytically.


Prior to these methods, the first "professional applicators" of the oldest method of rust treatment were probably blacksmiths. To protect their tools, the smithies would coat them with oil and heat them in their forges, not unlike the method of seasoning a cast-iron skillet. This process creates a hard coating, called magnetite, on the metal surface. This coating is chemically inert and will not react to oxygen or moisture. The path from the blacksmith shop to auto parts counter ran through the mining, construction and agricultural industries as scientists attempted to solve the problem of preserving metals exposed to the elements.


For modern automotive applications, rust converters come in the form of primers designed for use directly on the rusty surface, with no scraping, grinding, sanding or blasting. In fact, the product has to be applied to rust in order to work. The two components of converters are tannin and an organic polymer. Tannin, a water-soluble natural product derived from a variety of plants, reacts with iron oxide changing it to iron tannate, a stable blue/black corrosion product. The polymers provide the protective primer layer.


Like anything else, proper application with the best rust converters is key to a rust-free future. While you can toss your grinder and sandpaper, you still have to start with a clean, dust-free surface. A soft wire brush is the best tool to remove any errant particles, followed by a thorough vacuuming of the impacted surface. Soluble salts, like those used to de-ice winter roads, should be rinsed with water, and road grease needs to be removed as well.