How To Deal With Rust On Your Car

This is a common problem in cars, especially the ones that run regularly in water on intervals. Rust is the layman’s term for the electrochemical breakdown of iron-based metals called oxidation. In this process surface molecules react with oxygen in the air and produce a new molecule, Fe2O3, otherwise known as iron oxide. Iron and most steel will completely reduce to iron oxide and constituent elements given enough time.

Common places to find rust in a car are the under parts since this parts are often in contact with water, mud and dirt. Though there can be signs on the upper body of the car too. Some of these rust spots appear as little patches or bubbles on the paint surface of the car. Occasionally called “cosmetic rust,” there’s no doubt that it’s ugly but it’s also fairly localized. But it’s nothing to worry about, most rust cases are fixable as long as you attend to it immediately.

Rust Removal Technique

We have about 4 types of rust treatments

Physical Removal which is practical. Use a sandpaper, grinders and wire brushes! Physical removal of rust involves using something harder than the rust you want to remove and using it to wipe off that iron oxide. Wire brushing will take the longest time, sandpaper is better and if you use a power tool or air tool it’s even faster. Grinders are great if you have a lot of rust on heavy metal where there is no danger of ruining the base steel. Abrasive blasting (also known as Sand Blasting, but never use sand due to Silicosis) is also an option and while dirty and sometimes expensive, it does a great job of getting in to all the nooks and crannies. All physical means of rust removal will produce heat as a by-product. Depending on how thin the metal is below the rust, this may warp the panel you are working on. Care should be taken to minimize heat buildup.

Chemical Removal is the use of chemicals to remove rust in the form of acid. There are several products in the market that have some form of acid (Phosphoric Acid typically) and can be applied to rust. Care should be taken when using these chemical rust removers as they are mild acids and can cause damage to human tissue. The advantage of using chemicals is that there is a lot less manual labor, and the liquid can squeeze in to cracks and crevices which a wire brush or sandpaper can not.

Encapsulate Or Seal The Rust takes away one element of the elector-chemical reaction and rust can not form. If you can keep oxygen from getting to the base metal you can halt the rust process. If the rust you are treating is not affecting the structural integrity of the part and you don’t care what the final finish looks like, you can simply seal over the rust and be on your way. Some rust sealers can be top coated and even filled with body filler and sanded for a smooth finish but if you are going to this extent, you should consider removing the rust first.

Rust Converter which is similar to encapsulating, rust converters seal off the base metal from oxygen using a coating of the rust itself. The rust is chemically converted into a hard durable layer which does not allow the oxygen in the atmosphere to further react with the metal underneath. The advantages of using this method is that the rust converter is usually water soluble and safer than using acids.

Rust Treatment For Various Parts Of The Car

With vehicles, rust can pop up anywhere. There are various treatments recommended to use on different parts.

Body Panels: Physical removal, followed by chemical removal for pits or crevices. Immediately follow up with an epoxy primer and finish panel with your paint of choice.

Frame Components: If you have light rust encapsulator paint is the quickest way to stop the rust and provide a finish which is presentable. If you are restoring a car and want the best possible finish, physical removal followed by chemical removal and top coating with an encapsulator will give you the best finish and protection.

Wheels:  If you have steel wheels, you may also have rust. It’s recommend sandblasting as the easiest way to remove the rust and prepare the base metal for refinishing. If you are going to use a wheel cover over the steel wheel encapsulator will work just fine.

Exhaust: There are high-temp paints out there that will keep rust from forming. You can physically remove the rust from exhaust components and top-coat with paint. This will extend the life of your exhaust but given the environment your exhaust system lives in (high heat and moisture) it’s a losing battle. Some modern cars use stainless steel for it’s corrosion resistance, mostly costly but usually lasts the lifetime of the vehicle.

You can contact our service team HERE for more advice.

About Nonso Okafor

I've worked as a technical support representative in major auto centers in Nigeria for more than twenty years. I have dealt with a variety of problems in my capacity as a customer service representative and auto diagnostics expert. I'm committed to assisting people in properly maintaining their automobiles and in appreciating this magnificent innovation known as an automobile.

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