How to Fix Rust on A Car
Estimated Read Time: ~6 mins
At CarLotz, we see it every day. It takes only a glance to make that first—and often final—impression. When the time comes to sell your car, you usually have one opportunity to pique the interest of potential buyers, so make sure the first impression counts. It can mean the difference between selling or not selling your car.
One cosmetic issue that can be a major hurdle for potential buyers is rust. In many states, rust can cause a vehicle to fail its safety inspection, so whether for looks or safety, even minimal signs of rust can be a turnoff for buyers. Rust doesn’t heal itself, so if you want your car in tip-top shape for potential buyers, you may have to invest a little effort. Solutions to patch up rust vary depending on the degree of rust damage, so a thorough visual inspection will help you determine what steps you need to take. Whether the job is big or small, investing the time to remove rust from a car before you list it for sale will ensure your car sells quickly and for the most money possible.
Fixing rust on your car can be broken down into 8 straightforward steps.
Continue reading to learn more about how to fix rust on your vehicle!
What Causes Rust on Cars?
Rust, a reddish or yellow-brown flaky coating of iron oxide, is caused by three primary circumstances. The biggest factor is the weather. When metal is left outside long enough, it begins to oxidize, particularly on chrome or metal bumpers. Chipped or scratched areas of a car are even more vulnerable. In general, metal exposed to rain, sun, and other extreme temperatures is one of the fastest ways for a car to rust.
Cars in coastal regions are even more susceptible to rust. Salty sea water is the mortal enemy of metal objects and aggressively causes rust. Climates with extreme heat and cold have a similar effect. The final cause of rust is controllable, but it’s up to you. Failure to clean your car properly, leaving it outside, or neglecting to wax it will leave it open to infection. Be proactive by keeping your car clean.
How to Fix Rust Spots on a Car
Fixing rust spots on a car boils down to seven steps and access to a well-ventilated, well-lit garage or similar workspace. Don’t do this outside. The following instructions can fix small rust scrapes and dents, as well as rust holes.
To fix rust you’ll need a few vital tools. All the following can be bought or rented from your local parts or hardware store.
- Breathing mask or respirator
- Electric drill with sanding disc attachment
- Protective goggles
- Hammer (Ball-peen works best)
- Paint primer
- Rust resistant primer
- Grinding wheel
You may find chemical rust remover helpful. It isn’t always necessary, but it sometimes can be used instead of a grinder. Matching your paint color is tough to do, too, but it’s possible. If you’re having trouble, talk to your local parts store, as they can likely help you find the right paint for your car. As far as sandpaper goes, you’ll want a range. The 80 grit is generally best for metal, and 120–150 grit is best for removing paint and shaping patches.
Safety is vital no matter the job but is particularly important when you’re using a grinder, which can kick up sparks toward your eyes. Use proper safety goggles—regular prescription eyeglasses will not cut it.
Sparks are painful on bare skin, too, so wear long sleeves and pants regardless of the season. Long clothing also protects you against cutting yourself on sharp edges.
Finally, we’ll be kicking up a lot of dust, which can wreak havoc on your lungs. While a regular surgical mask is a great start, consider a respirator due to the nasty chemicals involved.
Now that your safety gear is on, and you’ve put the car in a well-lit garage (and cleared out everything that can’t get dirty), it’s time to prepare the car.
Mask every part of the car that won’t be painted with masking paper (newspaper works fine) and masking tape. If you’re using a primer, mask as much as you possibly can, leaving only a few inches on each side of the visible rust. If you’re painting to match the car’s body color, it may be more effective to paint the entire panel rather than one spot.
Even if you’re not planning to prime the vehicle, mask nearby panels because sparks can ruin paint. This includes delicate parts of the vehicle like tires, glass, chrome, and any part of the car susceptible to heat.
Using 80–150 grit sandpaper with a sanding block or mechanical sander, get down to the bare metal or the rust. This means removing all paint covering the affected area and adjacent components. While wearing goggles, grind away all rust. Before moving on, make sure the area is perfectly smooth and ready to paint.
Paint the rust holes border with a rust resistant primer or convert, according to the manufacturer’s instructions and waiting the recommended amount of time.
If you’re using body filler to fix a rust hole, mix the paste with the hardener as per the filler kit instructions. Don’t add too much, as it will thicken up. Then insert the included zinc metal piece behind the hole, attaching it to the car with small amounts of filler. Continue applying until the hole is completely filled and contour the paste to the vehicle’s body. Once that’s complete, let it dry.
As the primer finishes drying, sand it down with 180-grit sandpaper until it’s completely smooth. Then, take a finer grit sandpaper (120–150) and continue smoothing by hand to prevent too much of the panel from being removed. Once the surface is completely dry, spray on a thin layer of primer and let it dry completely, sanding for smoothness.
Once this is complete, add another layer, let it dry, and sand it smooth. At this point you can decide if you want to prime again or paint. If you choose to paint, smooth it out once more with 400-grit sandpaper and a flexible sanding block. Do not do this with an electric sander.
Once the surface is smooth, dust free, and dry, it’s ready to paint. Avoid excessive thickness or drips in the paint. The goal is for a thin, even coating with no thick spots. Let the paint dry, then hit the spot again with 400-grit sandpaper, paying close attention to any thick spots of paint. Clean it off, let the paint dry, and repeat. Repeat the entire process for three coats of paint. Finish with a wet sand, using only water and 400-grit sandpaper.
Once you’ve completed sanding, painting, and everything has dried, finish by applying a clear coat. This protects the layers of paint that you’ve added to the car and gives it a glossy, new look. Once this is applied, let it dry, then inspect to ensure there are no uneven parts and sand any that you see.
Fixing Rust on Car Frame
If the rust has already caused structural damage, turn to professionals. Rust on any part of the car that supports weight, is part of the suspension, or support structures can jeopardize the structural integrity of the car. Do not try to repair this at home. Instead, talk to a fully licensed mechanic or body shop professional.
Fixing Rust on a Car
Rust is seriously problematic. Take care of signs of rust right away. Not only can rust significantly reduce the value of your car, it can cause structural problems that may make the car unsafe to drive and impossible to sell. Once your car is rust-free and ready to go, CarLotz can step in and take care of the rest, helping you get the best value for your car with the least amount of hassle!