How To Fix Major Rust On A Car


Our cars are major parts of our lives. We do our best to take care of them, but the truth is they’re prone to some serious ailments. One of the more serious problems cars encounter is rust. Even minor rust spots can be a visual turnoff.

More severe rust can impede the safety of the vehicle. Any way you cut it, rust isn’t something you want on your vehicle. In this article, we’ll discuss what causes major rust on vehicles. Then, we’ll talk about the steps needed to fix rust and recommend some useful products along the way.

What Causes Rust?

Simply put, we have science to blame for rusty cars. Specifically, rust is formed when iron (like that found in steel vehicles) is exposed to moisture and oxygen. It’s important to understand that not all steels are created equal, too.

Older vehicles used steel that was much more prone to corrosion and rust. More modern vehicles use galvanized steel, which is much more corrosion-resistant. Modern paint jobs also go a long way in preventing rust. However, even modern vehicles can rust when that steel becomes damaged or modified.

The scientific name for rust is iron oxide. For iron oxide to form, three things need to be present:  a cathode, an anode, and an electrolyte. When it comes to cars, the steel provides the cathode and anode. The electrolyte comes in the form of water. Areas prone to heavy rain and snow tend to produce more rust in vehicles.

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Salt is also a huge enemy in the battle against rusty vehicles. Salt increases the electron-producing qualities of water. So, areas around oceans tend to have more rusty vehicles. Areas with harsh winters also produce more vehicle rust thanks to the salt used on the roads.

The good news is that if your vehicle develops some rust, you don’t have to send it straight to the crusher. What follows are the steps to take in repairing major rust on your car.

7 Steps For Removing Rust From Your Car

Step 1. Get The Right Tools

The first step in repairing major rust on your car is to get the right tools for the job. The bad news is that to effectively make the repair, you’ll need quite a few tools. The good news is that the tools aren’t all that expensive. In fact, there’s a good chance you already have most of them in your garage.

Your most important tool will likely be an electric drill or angle grinder. This will be your “sword” in the battle against vehicle rust. With the appropriate wheels, pads, and accessories, you’ll easily be able to cut through the surface rust.

You may also need to use a hammer and chisels to remove entire sections of damaged steel. These more drastic steps will require welding in patches of new steel or replacing panels entirely. That may be out of your league, in which case you’ll need to bring in an experienced welder. The ultimate goal is the same, though. You want to get down to pure, clean steel before you repaint.

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Speaking of paint, you’ll also need some paint-specific supplies to complete the repair. Specifically, you’ll want sandpaper ranging from 80 to 400-grit, primers, and paints. Before you use any of these tools, though, you’ll need some safety equipment.

Step 2. Get The Right Safety Equipment

Rust can be severely damaging to your car, but it can do even more damage to your body. Sucking a bunch of rust and/or paint particles into your lungs will quickly ruin your day.

Likewise, getting metal splinters in your eyes or buried in your thumb is not a good time. That’s why it’s important to have the appropriate safety equipment before you start any rust repairs.

You’ll want a quality respirator, gloves, and eye protection. As for respirators, I’m a big fan of the GVS SPR457 Elipse P100 half-mask. It’s a great “multi-tasking” respirator. It comes with reusable filters and does a great job of protecting from dust particles and paint fumes. It’s also great for dudes with beards.

How To Fix Major Rust On A Car

My favorite feature of the mask, though, is its low profile. It can be worn under a welding helmet—a big bonus for me. Finally, it comes at a price tag that won’t break the bank.

Gloves and eye protection should be pretty obvious, but you should also consider your clothing. If you’re doing a lot of sanding and grinding, you can expect dust and metal particles. Those particles can hurt if they hit bare skin. It can also be a pain to wash all that grit off. So, we suggest wearing pants and long sleeves when you’re doing any kind of rust repair.

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Step 3. Prepping The Car

Like many vehicle projects, the preparation for rust repair is just as important as the task itself.

Your first job in the prepping process is to make sure you have a good location to work. A clean garage is the obvious choice. However, take the time to move anything in your garage you don’t want to get covered in dust. You may also want to tape up some plastic drop cloths to protect any areas you don’t want to get filthy.

Now, it’s time to prep your car. In a nutshell, you need to cover every part of your car that you won’t be repairing. You don’t need to purchase a bunch of fancy painting supplies to accomplish this. Simply put down some newspaper on the areas of your car you won’t be sanding or painting. Secure the paper with painter’s masking tape (OK, so you might have to purchase one painting supply).

Remember, if you’re going to be grinding, you’re going to be flinging hot sparks. Those sparks can damage things like clear coat, chrome, or even your tires. That’s why it’s important to mask off every part of your car you’re not working on.

Step 4. Sanding The Car

Look, you’re going to be doing a lot of sanding during this repair. You’re also going to need a lot of sandpaper in a variety of grit-counts.

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Start off with the heavy-duty stuff—80 to 150-grit. The goal is to sand down your paint and rust until you get to clean, bare metal.

When you’ve got the surface nice and smooth, it’s ready to paint. You can use an electric sander or drill, which will make the job go a little quicker. However, if you’re not used to using the sander, we suggest using a sanding block and going by hand. It’ll take longer, but the process is far more forgiving when it comes to slip-ups.

Our preferred sanding block actually comes as a 7-piece kit from Eastwood. It’s a bit pricy when compared to other, single blocks, but it’s worth it. The variety of sizes and contours in this kit will ensure you can tackle any repair anywhere on your car. Plus, when you’re using an Eastwood product, you’re backed by the premier autobody repair company in the industry.

How To Fix Major Rust On A Car

If the rust is bad enough that you have holes in the body, this is where you’d patch them. Normally, you would either weld in new metal or use a body filler like Bondo. Those tasks deserve their own, separate articles. Regardless of whether you’ve had to weld, Bondo, or just do some sanding, the goal is the same. You want a nice smooth finish that you can paint.

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Step 5. Priming (And More Sanding)

Now we’re getting to the good stuff. The next step in your rust repair is to spray a paint primer on the area you’ve prepped.

Again, when it comes to primers and paints, we suggest going with the Eastwood company. They’re not the cheapest, but we believe they’re the best.

You’re going to be applying several layers of primer and paint, so don’t go crazy. Apply only a thin layer of primer the first time around. When that first layer is almost dry, use 180-grit sandpaper to sand it back down until smooth. DO NOT use an electric sander for this process. This one takes some finesse, so you’re better off using a sanding block. After a few passes with the 180-grit, switch to something a little finer (like 250-grit) to continue the smoothing.

Allow the first layer of primer to dry completely, then repeat the process—prime and sand. You may choose to add one more layer of primer, depending on how severe the damage was.

Regardless of how many coats of primer you apply, your final application should be followed by one more sanding. This final sanding should be done with 400-grit sandpaper on a sanding block. Sand the primer smooth and at this point, you’re ready for paint.

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Step 6. Painting (And More Sanding)

Apply your first layer of paint in a thin layer, just like you did with the primer. If you go overboard, you’re going to wind up with runs or drips in your paint. The goal is a thin and even layer of paint. When the paint is dry, hit it again with your 400-grit sandpaper.

If you’ve accidentally created a couple of thick spots in the paint, use your sanding block to knock them down. Blow off any dust you’ve created, and repeat the process two more times. After your third layer of paint, you’ll “wet sand” the repair area. This process is the same as you’ve been doing, you’ll just soak the area with water while using the 400-grit sandpaper.

Step 7. Apply Clear Coat

The final step in your rust repair job is to protect all your work. To do this, you’ll apply a layer of clear coat on top of the new paint you’ve laid down. This clear coat will protect your paint job from any minor nicks or fading. You’ll be left with a clean, glossy finish and a feeling of pride at having repaired the rust yourself!


As you can see, repairing rust on your vehicle isn’t necessarily difficult, but it is time-consuming.

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Perhaps the best advice we can give you is to catch the issue early. If you notice rust spots on your vehicle, don’t wait to fix it!  The longer you wait, the more severe (and costly) the repair will be.

If your vehicle has rusted through, you’re looking at welding (which isn’t easy or cheap). Your other option is to replace an entire panel (easier, but also not cheap). But if you can catch the issue before it gets out of hand, the above steps will have your vehicle looking great in no time!

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