Usually, once rust has settled on metal, it's almost impossible to remove. It's almost too late before a car owner finds out that rust has eaten most of the car's fender, or the small bubbly stain has become a large rusty puddle on the hood. Also, it's very expensive to have your car professionally treated for rust. This is why the best way how to stop rust on car is to prevent it from happening.
The Different Types of Rust on Car
Not all rust on cars is the same. So the first way to get the rust off a car is to find out the type you're dealing with. The three types of rust are surface rust, scale rust, and penetrating rust.
- Surface rust
Surface rust is rust that's in its earliest form. The rusting part of the metal is only the top part of the car body. You must treat surface rust quickly before it becomes worse.
- Scale rust
Scale rust happens when you allow surface rust to remain on the metal. Rust starts to create small pits on the metal surface, and corrosion becomes harder to control. Treatment for scale rust should be very aggressive as you need to save much of the metal as you can. Scale rust reduces the strength of the metal
- Penetrating rust
Penetrating rust is the worst kind of rust because it has already corroded the metal enough to create holes on the metal. It’s too late to remove rust from the car with penetrating rust. A complete and costly body overhaul is needed. When penetrating rust is present, steel becomes very brittle and is now known as iron oxide.
Tips on How to Stop Rust on Car
Carmakers are very concerned about corrosion on their products. This is why extensive testing of different materials is done to keep cars free from rust, even in very challenging environments. Nowadays, steel has been replaced with aluminum as well as magnesium metals to prevent rust. These materials are also lightweight and thus ideal for making high-performance cars. However, the problem with these materials is that these are very expensive.
Meanwhile, modern steel comes in rolls coated with a very durable paint to resist rust. As this coated steel is cut to make car parts, the resulting part is further dipped in anti-corrosion chemicals before these are painted.
Most cars have very thick paint coating along the underside of the body. This thick coat helps seal the steel from any corrosion. The outer side of the car body is also subjected to extreme moisture and dirt, making paint coatings wear off in a matter of time. Therefore, the key is to regularly inspect your car against rust to deal with surface or early-forming rust.
How to Prevent Rust
- Wash your vehicle regularly. This includes the underside of the car and not just the car surface. Washing the underside will help clean any grime, dirt, and salts which start corrosion.
- Check the drain holes along with the rocker and door panels. This is where rainwater flows out to drain and is also where rust starts to form on doors.
- Always dry your vehicle to avoid moisture from forming in different places and causing rust.
- Use a rust aerator. This is a product that can prevent the development of new rust. It comes with a small brush to help you apply a thin layer of the product. Let it dry completely. Rust aerators are available in a car parts store.
How to Deal with Rust
1. Surface rust
- For surface rust, use sandpaper to treat the corroded surface. The sandpaper will remove any remaining paint and remove all surface rust. Sand the area until you see bare metal.
- Once the bare metal is visible, apply a coat of automotive primer and let this dry. Apply paint of your choice. You may choose to apply two coats or more, but you may also use one coat of paint to just top it off with a clear coat.
- Buff the treated area to blend all the paint finishes.
2. Scale rust
- Remove all visible signs of rust using a wire brush. You need this tool because the damage is more serious and has created a noticeable pit.
- Sand the area to get a smooth and clean surface. Just like removing surface rust, don’t stop until you see bare metal.
- Apply automotive primer and follow up with paint. You may apply a clear coat of paint if you wish to completely seal the corroded area.
3. Penetrating rust
- Most cars with penetrating rust are done for. The only way to save the vehicle is to replace the affected part. You’re lucky if the part is a small one like your fender or the car door, but if you’re dealing with the hood or the entire body, then you may need to pay so much for a panel replacement.
- Some car owners go for a cheaper alternative, and that is to use metal patches to cover the decaying metal. If this is your option, make sure that you deal with the penetrating rust first before you patch it.
Use a sander to remove all signs of rust. This tool can scrape the car to the bone to expose the fresh metal. Once you see bare metal, use coarse sandpaper to clean all the edges. Apply automotive primer and paint.
The patch has to blend well with the surface of your vehicle. This piece is welded to the top of the hole and then sanded to make the area smooth and perfect. Once the patch is barely noticeable, you may now apply a coat of automotive primer and paint. Buff the area well before applying the final layer of clear paint.
Dealing with rust can be expensive and time-consuming. It’s very important not just to learn how to stop rust on a car, but to prevent dust and keep this from forming on your car. We recommend having your car maintained regularly because a part of proper car maintenance is rust prevention.
James is a certified auto technician specializing in commercial vehicles. With 30 years of experience under his belt, James has encountered almost every type of automotive issue there is! Besides his day job at the repair shop, he is also an amateur race car driver.