How to Fix Rust Holes on a Car

Not only are they unsightly, rust spots can also spell trouble for your car and your wallet.
Written by Brenna Swanston
Reviewed by Carrie Adkins
Once the
rust battle
has begun on your car's exterior, it is never truly over.
That being said, where there is rust, there is usually more to come. If left unchecked, a rust problem could
wreak havoc on your car
and cover it with holes in no time; however, if you catch surface rust on your car and nip it in the bud, you can squeeze a few more years out of your vehicle.
Here's a step-by-step guide to fixing rust holes on your vehicle.


Before fixing the rust spots on your car, you need to make a few preparations.
First, wear protective goggles or a face shield. Rust removal may cause flying debris that could potentially damage your eyes.
Next, it’s a good idea to protect the rest of your car and your workspace. Drape the area with a plastic tarp or fashion one out of newsprint, trash bags, and masking tape.
Remember to select a well-ventilated work area, and wear a mask to prevent breathing in sanding particles and harsh chemical fumes.

Removing the Rust

The fastest and most efficient way to remove rust is to use an electric drill with a wire brush or sanding attachment. 180-grit sandpaper is ideal; however, if you're in a bind an angle grinder outfitted with an abrasive flap disc will also do the trick.
If you don’t have any of these tools on hand, most hardware stores rent them out. Follow these steps to remove the rust.
  1. Sand away the rust and paint: Remove the rust and paint within two to three inches of the hole. For medium-sized rust holes, sanding and repainting the entire body panel will help to achieve a more seamless look.
  2. Apply primer: Your freshly-sanded metal could rust again if left untreated. A thorough coat of a rust-inhibiting primer such as Rust-Oleum will prevent new rust from forming. You can find this at most hardware shops. Some rust primers are sprayed on, while others must be applied with a brush. Whichever you choose, follow its instructions to the letter. Allow it to dry completely before moving on to the next step.
  3. Smooth the edges: In some cases, you may be left with rough edges around the rim of the hole after you're finished sanding. That’s ok! Take a ball-peen hammer and gently tap the edges inward. This will help you achieve a smooth and even surface once you’ve filled in the hole.
  4. Fill the hole: Filling the hole will require a body filler kit. These can be found at any major auto supply or hardware store. The exact contents of these kits may vary, but they will always include a body filler putty (to fill the hole), a hardening solution, an adhesive metal patch (to support the putty), and an applicator tool. Mix the putty with the hardening solution, adhering to the kit instructions. Dab a generous amount of putty around the outer edges of the metal patch and place it behind the hole. This will provide a supportive backing to the putty. Use the applicator to fill the hole with the putty mixture and allow it to dry thoroughly.
  5. Sand and prime: Once the putty has set, use fine-grit sandpaper to sand the putty until it's flush with the panel. Be careful not to apply too much pressure to the hole as you sand. Before painting over the filled hole, apply several coats of primer. Two to three coats of primer should suffice. Allow each coat to dry completely before sanding it down and adding another coat. It may seem like an excessive amount of sanding, but it’s crucial that the surface is completely smooth before applying the paint.
  6. Paint over the filled hole: A messy
    paint job
    will only draw attention to your repair. Avoid drips and uneven brush strokes. The best approach is to apply multiple thin coats with a steady hand.
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