Prevent, Treat, or Remove? How to Deal With Rust

As automotive enthusiasts, our love of cars extends beyond the thrill of the drive. Gleaming paint, pristine bodywork, and meticulously maintained chassis all add to the pride of ownership. But lurking just below the surface often awaits a silent and relentless enemy – rust. Driven by a complex interplay of environmental factors, it poses a serious threat not only to the appearance of our rides, but also their fundamental integrity.

In the perpetual battle against corrosion, we must equip ourselves with a robust arsenal of measures to either prevent, treat, or remove this enemy. From cutting-edge rust inhibitors to the meticulous work of surface restoration, here’s a look at what weapons you might choose based on the degree of damage already done.

Prevention

Perhaps the best way to deal with rust is to never have it show up in the first place. As the old adage goes, “An ounce of rust prevention is worth countless hours and dollars thrown at fixing it.” Or something like that. Seriously though, a bit of investment up front to keep rust at bay could save you untold headaches down the road.

Whether your vehicle is brand new or just newly restored, start off right by protecting the areas most vulnerable to corrosion. A simple rubberized undercoating on a car that sees regular road use will prevent the paint chips, which is often how rust starts from the outside. Pay attention to lower areas especially, such as floor pans and steel fender arches.

Of course, rust can also start internally and works its way outward in areas like frame rails and rocker sills. You can treat these areas with an internal frame coating to prevent damage from within. This product can also be beneficial on older vehicles where corrosion may have already started, as it has an encapsulating property that seals off existing rust and prevent it from spreading further.

Even bare metal can be treated to prevent corrosion. A product like ExoArmor can prevent rust from starting on steel brake and fuel lines as well as iron castings and other unpainted trim and components. Originally developed for military and aviation applications, it’s ideal for preservation projects or when a bare metal finish is desired.

Treatment

Sometimes, despite your best efforts, rust happens anyway. It’s a fact of life, especially with older vehicles. You simply can’t protect every square inch of metal from the ravages of time and moisture. But often there are ways to treat metal and stop the corrosion in its place before it’s too late.

There are a couple different approaches to treating rust depending on its severity and whether or not the rust affects the appearance. The first is to chemically convert the iron oxide into a more stable material. The other is to “trap” the rust in place and seal it off from the elements to prevent further spread.

Rust converters use a phosphoric acid solution to change iron oxide (rust) into a more stable iron phosphate, which is less reactive with oxygen (including that in water). The surface is left with a black finish when conversion is complete, after which it can be painted. This solution works best in situations where there is heavy rust. The phosphorus reacts only with the rust but not good steel or iron. It also doesn’t react with paint, other than to make it sticky afterwards.

Treating with rust converter requires minimal preparation. Simply brush off any loose flakes of rust or paint, then apply the solution to the surface. It can be sprayed or brushed on and then rinsed off when the conversion is complete. It’s recommended that the surface cures for 48 hours before painting, however.

Rust encapsulators are exactly what they sound like – a paint that traps seals off rust and prevents it from spreading. Available in a variety of colors and textures, these provide a top-coat finish once applied and require only minimal prep work. Brush off any loose scale, degrease the surface with a prep solvent, and you’re ready to go. Once dry, the surface is sealed to prevent further rust. It can also be painted over if you prefer a finish other than the colors offered.

Removal

Of course, sometimes it’s too late to save a rusty part from its inevitable demise. Even the best preventative measures will eventually succumb. The only solution for severe rust is to remove and replace.

Bolt-on body panels like hoods and fenders can easily be exchanged for new or better-condition used pieces. But in the case of welded body assemblies or structural components like chassis frames, you may need to repair the existing part in place. Patch panels are a common way to make localized repairs to common body corrosion, though they’ll require some welding. The same is often true for frame sections, which can cut and spliced with new metal.

The key to any of these repairs is the complete eradication of rust in the old components. First, you will need clean metal to weld your patches to. Second, you also want to make sure you’re not starting out with an “incubator” for new rust by leaving old corrosion behind. Grind the rusted areas back to clean metal before trimming your patches.

Once repaired, clean your weld areas properly and seat the bare metal with an etching primer before painting. Oh, and don’t forget to treat the newly repaired areas with preventative measures. After all, why start the process all over?