How to Remove Surface Rust from a Car (Small Rust Spots)

We depend on cars for a number of things, from commuting to and from work to running everyday errands. Unfortunately, their engines don’t last forever, and the same can be said for their metal exteriors. Although it’s easy to believe that once rust begins to form on a vehicle, it’s done for, think again; there are actually a few ways you can remove surface rust from a car.

How do you remove surface rust from a car? To remove surface rust, you will need to remove the paint and primer from the area before sanding it down and reapplying a fresh coat of primer/paint. Alternatively, you can also use a specialized chemical rust removal product.

Either process sounds simple, but it depends on how deep the rust has penetrated the car’s surface and how much work you’re willing to put in to get it removed. Some people may opt to take their vehicle into a body shop to have special rust treatments done, but you could also save some money by treating it as a DIY project. However, if you want to remove rust and prevent it from coming back, it’s first essential to understand how it forms.

Removing rust from an old car with a grinder machine.

What is rust?

To get scientific, rust is the oxidization of iron molecules in metal. Iron molecules bond with oxygen and moisture in the air and create a new molecule. This molecule weakens the integrity of the metal, which can lead to massive structural failures in a car’s framework if left alone.

The steel that most cars are made from is itself made from iron—leaving a vehicle susceptible to rusting simply by being exposed to air and water for long periods. However, there are things you can do to prevent rusting, as well as treat already rusted metal.

How to Remove Surface Rust from a Car

If you are starting to see signs of rust on your car, take action immediately to prevent the rust from penetrating deep into the metal and spreading. Attacking rust while it is only on the surface can save you from more significant issues.

Before You Get Started

Before you get started, here are some quick safety tips to remember:

  • When working with paint, make sure to work in a well-ventilated area. Paint fumes can be dangerous when inhaled.
  • When sanding things down, consider wearing a face mask, and maybe goggles too. The process of sanding anything down causes tiny particles to fly off your work and into the air. There are a lot of dangers from breathing in foreign particles, even in small doses, and you don’t want them in your eyes either.
  • Consider gloves when using power tools.
  • Power tools are precisely what the name suggests: powerful tools. Anyone working with them, especially if you’ve never worked with them before, needs to be extra careful. Having a thick set of gloves on will only protect you to a certain point, but you might be thankful for that barrier if accidents happen. In other words, always use the proper PPE (Personal Protective Equipment) when working with tools.

Step 1: Tape off the area you plan to treat

Whenever you are painting or working with paint, it is a standard practice to tape off the surrounding area to prevent the accidental contamination of clean spaces. The same idea applies to vehicles.

First, wipe down the spot you plan on working on thoroughly, removing any dirt and other particles from the car’s surface. From there, you will want to tape off the area and cover the rest of your car’s surrounding paint job to prevent any rust particles from staining or getting on other places while you work.

However, don’t use just any kind of tape on your car’s exterior. Not all tapes are created equal, with some manufactured with so much adhesive that it will pull the paint right off the vehicle’s surface. Avoid using duct tape (which is designed for heavy-duty work and to stick for more extended periods) and basic office tape (which is designed for the complete opposite).

The ideal tape you should use is a type of painter’s tape or masking tape, both of which can be purchased at a low price on Amazon.

Masking tape is made for paint projects specifically. It’s not as adhesive and made to be pulled off easily. The blue masking tape is often better quality than the brown tape if a little pricier. But it should peel clean off, leaving no residue and taking no paint with it.

Step 2: Remove the paint and primer from your car

This next step might be one of the most nerve-racking steps of the process. Nobody likes a damaged paint job on their car. But, to remove the rust from the surface of the metal, you must first remove the paint and primer.

To do this, you need to first sand off the paint and primer. You can do this manually with a sheet of sandpaper (Amazon), starting with a low grit and moving up to a high grit paper, or you can do it with the careful application of a hand sander.

If you’ve never sanded down anything before, you’re going to want to do this slowly and by hand. Typically, when sanding, you want to use at least three different grits of sandpaper one at a time. Do this until you have removed all the paint and primer off the work area.

The grit or gauge of sandpaper is essentially a grade of abrasiveness. The lower the grit number, the rougher it is, with large, abrasive particles. In general, you will use the rough abrasive paper to start with. You then move onto a higher gauge sandpaper, which is finer with smaller abrasive particles that will leave surfaces smoother.

It is highly recommended that you start with 80-grit sandpaper and end with a 150-grit when removing the paint and primer off your car.

Step 3: Manually remove the rust

There are several different tools to choose from that will get the rust off your car.

The first is sandpaper: if the rust is really shallow, you can sand it off the same way you sanded off the paint and primer. This will only work if you have caught rust early, or if you’re going to put a lot of elbow grease into it. Otherwise, you might be better off using a power tool.

You can also use an abrasive wheel or a metal grinder (Amazon) to remove the surface rust too. Be cautious when using one of these tools, and make sure only to remove the rust and not damage the metal underneath; power tools are great resources for the new DIYer and novice mechanic, so long as you pay attention to what you’re doing.

Continue to sand or grind down the area until you see clean metal; if you’ve reached this point, then you have successfully removed the rust from your car!

Other Rust Removing Products

There are plenty of alternative forms of rust removal that don’t require quite as much elbow grease. Chemical rust removers come in liquids, gels, and soaks (Amazon) that can do most of the work for you.

Each of these products is unique and requires special handling, but generally, all you would need to do is to apply the remover with a rag or possibly a paintbrush, to the area that you wish to clean, leave it on for the directed time, and then remove the treatment carefully.

Chemical rust removers are a great alternative to sanding and power tools if you aren’t confident with them, but they carry risks too. If you are using one of these products, make sure to read the labels carefully and follow the directions to avoid damaging your car or harming yourself. You should always use them in a well-ventilated area.  

After Removal: New Primer and Paint

Now that you’ve finished removing the rust from your car, you probably have a prominent spot in your paint job. Paint jobs can be very costly, even if it’s only one section of the vehicle’s surface. But you’ve gone so far as to remove rust yourself, so it should be easy to reapply your car’s paint and primer yourself too.

  1. If you are going to do this, you first might want to sand the work area down again. You need the space even and smooth before you can apply primer or paint.
  2. Then, you want to clean the area. Dirt, metal dust, or shavings can interfere with your paint and prevent you from getting a beautiful, even coat on. They can also cause bubbles in the paint, which can pop and attract rust all over again.
  3. Once your area is clean and dry, start in with the primer. It is possible to paint without a primer, but the paint will adhere better to a surface that’s been primed. Primer is designed to be a go-between for paint and all kinds of surfaces, and most paints are designed with the assumption that you will have primed an area first.

There are paint and primer hybrids available; sometimes, they can even be more cost-effective. But some people question the quality of these products, so make sure to do your research before you pick out the product you’re going to use.

  • Coat the area with the primer as carefully and evenly as possible, then let it dry. Painting and priming will be a waiting game, so make sure to bring your patience to the project as well.
  • Once the primer is dry, check for any bumps or imperfections. Sometimes drops can gather and dry out as bumps, and occasionally excess paint can gather at the bottom of your workspace. If this happens, you’ll want to sand down the uneven areas before you start in with the paint. It seems like a pain, but making sure the area is smooth will make such a drastic difference that, in the end, you will be so glad you did it.
  • Now it is time to apply the paint. You want to make sure that the color you are using is an exact match to the paint already on your car. Even the slightest difference in hue will haunt you; your eyes will never not see it. If you’ve got your color right, apply it evenly across the work area and wait for it to dry. You might consider using more than one coat of paint on the car. If you do, you will still have to make sure that your work area is even and smooth before adding the next coat of paint—sand, clean, paint, dry. Repeat for as many coats as you like.

Another layer that you could add to your paint job is a clear coat. A clear coat is a paint protector that also gives you work an extra shine to the finish. It can help prevent damage from the weather and even light scratches. If you are going to paint a layer of clear coat, follow the same recipe of sand, clean, paint, dry.

  • Finally, once you’ve applied all your primer, paint, and coats to your car, you can remove the tape from the work area. Once you do, you may find a clear distinction between your work area and the rest of the car. If you do, don’t be disappointed; this is something you should actually expect when you add a new coat of paint to an old car.
  • Now it’s time to buff the car; this will help to ensure a smooth blend of the old and new paint, blurring the difference between them.

Future Rust Prevention

Now that you’ve gone through all the trouble of de-rusting your car, you’re going to want to prevent it from happening again. Rust is an inevitable part of owning a car, but you can slow down the process dramatically with a little maintenance.

Here are some of the best things you can do to prevent rust before it starts:

Spray your car with rust prevention products

There are all kinds of rust prevention products for you to pick and choose from. Some of them are simple sprays (Amazon) for the car. They only take a few minutes to apply and last for months, helping better protect your vehicle from the elements. Do your research and find the right product for you and your precious ride.

Wash the underside of your car

Washing the underside of your car might not be something anyone ever thinks about, but it will help prevent your undercarriage from rusting. This is especially important during winter when there is salt on the roads that can exasperate rust issues—speeding them up and spreading them out, compromising the integrity of your whole vehicle. Wash the underside or find a carwash that cleans off the bottom of the car as well.

Wax your car

Waxing your car may seem like a fickle thing to do to some people, but it is actually very beneficial to the health of your vehicle. Car wax (Amazon) helps protect the exterior from the elements like UV light and wet weather, two significant factors that contribute to car rusting. Some car washes offer this service too if you don’t have the time to do it yourself.

Use a good car cover

You wouldn’t think a car cover can cause rust, but it can. All car covers are not made alike; some are better than others. If you are shopping for a car cover (Amazon), look for one made from breathable material. This will let moisture that might have collected inside the sheet out, preventing it from causing rust while your back is turned.

Fix chips in your paint job quickly

The paint on your car actually protects the metal beneath it from the elements. However, when there are cracks and chips in that paint, your vehicle is much more likely to start to rust. When you find issues like these, fix them quickly to avoid rust issues. Take them in, or hey, repaint it yourself!

Clean your wheel wells

Mud, debris, and moisture can collect in the wheel wells in your car. The detritus builds up in the unseen corners and can spread moisture and rust to the rest of your vehicle. Keeping these areas clean and moisture-free will significantly benefit the health of your car.

Clear out the drain holes of your car

Your car’s drain holes are what allows water to flow out during wet weather. Blockages and consistently wet drain holes are common causes of rust, especially near the doors. Check these areas and dry them regularly.

Final Thoughts

Rust is a major enemy to all things metal, but it can be costly and even dangerous in the case of your car. Make sure to take the issue seriously and try nipping it in the bud as soon as you see a problem. Your vehicle will last longer and look better if you do.

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