The 3 Types of Rust and How to Prevent Them Explained for Auto Body Repair Technician Students

As a car begins to age, one of its greatest enemies becomes rust. All cars are susceptible to the chemical process that happens when exposed steel on any part of a car’s body or undercarriage comes into contact with moisture, quickly turning from hard metal into the brittle iron oxide we know as rust. Although car manufacturers are coming up with ever better anti-corrosion coating systems for keeping the underside and surface panels of vehicles protected, rust is impossible to avoid altogether—especially for those frequently driving in harsh weather conditions.

To understand how to treat rust when it creeps in, let’s take a look at the three types of the dreaded substance.

Surface Rust 

You know the sound well—that awful ding when gravel or salt smacks into your car hood or door at high speed. Sometimes the offending object will bounce off, and your vehicle exterior will remain blessedly unscathed. Other times, your car will have sustained a tiny dent—exposing the car’s steel beneath the paint surface, making it at risk of developing the earliest form of rust.

This type of iron oxide, known as surface rust, is the least damaging, and can be beaten if attended to swiftly. To remove the rust spot entirely, ensuring it doesn’t continue to corrode the car’s surface, the patch should be attended to with fine-grit sandpaper until bare metal is exposed. This process will effectively remove the rust, but will also take some of the car’s paint off with it. To patch up the area, a coat of automotive primer must be applied, followed by a coat or two of paint matched to the car manufacturer colour code. A quick buff finishes off the patch repair.

Scale Rust 

If little dings, nicks, or scratches on a car are neglected for too long, surface rust will eventually evolve into scale rust. You’ll know this much more corrosive type of the substance by the small pits that begin to develop on the affected area, often accompanied by a tell-tale blistered or bubbled paint surface. Because this type of rust is much more damaging, it requires a more aggressive treatment approach so that the affected area can be saved and a much more expensive full part or panel replacement can be prevented. 

Car owners would be well advised at this stage to seek the assistance of pros with auto body technician careers. A wire brush must be used to scour the corroded surface, followed by the same techniques used on surface rust—rubbing the area clear with sandpaper until bare metal is exposed, followed by a primer, paint, and buff job.

Penetrating Rust 

If you don’t catch and remove scale rust in time, the corrosion process will descend into penetrating rust, which eats car metal for breakfast. At this point of corrosion, holes will begin to form and the affected car parts will literally start falling to pieces, compromising the structural integrity of the vehicle. 

The most common solution is to have an auto body repair technician remove the rust-affected part entirely, to be replaced with a new one. Less costly patch repairs are also possible in some cases—where the affected area is scraped away and covered over with a new welded on piece, then primed, painted, and buffed to blend in with the surrounding car surface as naturally as possible. 

What Those with Auto Body Technician Careers Should Tell Car Owners About Prevention

The best away to combat the horribly corrosive effects of rust is to prevent it from forming altogether. Car owners should be advised to wash their cars regularly to remove corrosive substances such as dirt, salt, and grime, which can trap in the moisture that accelerates the rust-forming chemical reaction. The underside of the car mustn’t be neglected, as the frame, suspension, and wheel wells are all prime rust-invasion zones. Regular waxings are also recommended for providing the paint coat with an added protective layer against nicks and scratches. 

Rust can be a nightmare, with its damaging effects often leading to costly repairs. Owners should remain vigilant about checking their cars for the first signs of rust, so the car can be quickly treated with touch-up paint or taken into the auto body repair shop for closer inspection. 

Are you interested in pursuing an automotive career by becoming an auto body technician? 

Contact Automotive Training Centres for more information on their auto detailing training program!