Auto Dent Repair: How to Fix a Dent in a Car

DIY dent repair saves hundreds of dollars

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Introduction

If you follow these steps, you can patch a car dent yourself in just an afternoon and save a few hundred bucks over body shop prices.

Tools Required

  1. Angle grinder
  2. Corded drill
  3. Dust mask
  4. Extension cord
  5. Hearing protection
  6. Safety glasses
  7. Sanding block

Materials Required

  1. Body filler
  2. Finishing glaze
  3. Latex gloves
  4. Sandpaper
  5. Tack cloth
  6. Wax remover

We’ve patched quite a few car scratches and dents in our day. We used to do it the same way we tape drywall, by applying five pounds of body filler and then sanding off 4-9/10 lbs. Then we went to “boot camp” at 3M and learned there’s an easier way (as in, the correct way) to do car body repair.

We asked expert Jenn Cook, a senior technical service engineer at 3M, to walk you through the same car dent repair process. Once the car dent repair is patched, you just spray on a primer coat and matching paint from the dealer or an auto parts store. The repair won’t look like a professional job, but at least it won’t stand out like a sore thumb. Here’s the process.

Project step-by-step (6)

Step 1

Prep and Clean Before Filling

Step 2

Remove the Paint

  • Start by removing the paint inside and around the dent with 24-grit paper.
  • Switch to 80-grit sandpaper and hand-sand the entire dent.
  • Use the same sandpaper to rough up and feather the paint around the edges of the dent.
  • Clean the entire area with wax remover and a clean rag.
  • Then wipe with a tack cloth.

Sanding the carFamily Handyman

Step 3

Mix the Filler

  • Spread the filler down the mixing board in an S-shaped curve.
  • Then scoop it up and fold it over.
  • Repeat until the filler has a consistent color.
    • Don't mix body filler on a scrap piece of cardboard. Instead, use a mixing board or an old, clean cookie sheet you're willing to toss.

Mixing the fillerFamily Handyman

Step 4

Apply a “Tight” First Coat

  • Scoop up some filler and press it hard into the rough metal.
  • Spread the filler to form a “tight” coat. That will burp air out of the scratches and wet the bare metal.

Adding the tight layerFamily Handyman

Step 5

Add More Filler

  • Wipe on a thicker "fill coat" layer of filler to completely fill the dent.

Adding the fill layerFamily Handyman

Step 6

Sand to Shape and Glaze

  • Sand the filler to match the contours of the car body using 80- and 180-grit sandpaper.
  • Then feather the edges of the filler right up to the painted edge.
  • Next, apply finishing glaze to the entire patch and then sand with 180-grit and then 320-grit sandpaper.
  • Spray the patch with primer, then paint it.

 

Sanding the patchFamily Handyman