Taking Out Little Dents





Introduction: Taking Out Little Dents

About: The official instructable for Popular Mechanics magazine, reporting on the DIY world since 1902.

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To fix a single dent (like the one pictured), it is probably not worth the time and paperwork it takes to fill out the insurance claim. Besides doing it your is easy enough --the tools won't cost much, and the instructions won't make your head spin.

You can bang out that dent, fill those nicks, and refinish that paint job with a body hammer and dolly, a sander with a 36-grit disc to remove paint, a putty knife and body filler squeegees to apply filler, a bodyworking file ("cheese grater") to level the filler, a stroke sander to smooth it, an air compressor and spray gun to apply primer/surfacer/paint, and a buffer to shine it all up. Thanks to today's body repair materials-better paints, improved fillers and two-part primer/surfacers-bodywork and painting to a mirrorlike finish has never been easier to do in your own shop.

Step 1: Bang It Out

To remove a dent, first gain access to the back side of the body panel by removing items like headlight buckets, inner fenders, door panels and interior trim. Then, place a dolly on the outside of the dent and then hammer on the inside of the dent, striking the metal against the dolly. The key is to go slowly and work around the circumference of the dent, banging it out until it lies just below the undamaged area. After the dent is out, put the dolly on the inside of the dent, then tap the area surrounding the outside of the dent to knock in any high spots.

Step 2: Prep and Apply Filler

When you're sure all the sheetmetal is just slightly below the surface of the surrounding area, use a disc sander with 36-grit paper to remove all paint and primer from the dent and surrounding area. This will give the body filler a rough surface (called tooth) to hang on to once it has hardened. After thoroughly mixing the filler with hardener, smooth it on the damaged area with a plastic filler applicator. The filler semihardens in 10 to 15 minutes to the consistency of cheddar cheese.

Step 3: Smooth and Sand Down the Filler

At this point it's easy to smooth with a body file. Use the file to knock the filler down so it is slightly higher than the finished repair will be. After about 15 to 30 minutes, the filler becomes hard.At this point you can use a hand or air-powered stroke sander with 80-grit paper to bring the filler down to the level of the body. If you see any bright, shiny metal spots in or around the filler, those areas are high. Use the pointed (pick) end of a body hammer to tap them in slightly, then refill and resand.

Step 4: Prime and Surface

Before the repaired area can be painted, scratches, pits and waves must be completely removed or they'll show up as reflections. A primer/surfacer forms a thick layer of material over the area, which is then sanded down to make the repair smooth and level. Two-part primer/surfacers, consisting of the primer and a hardening agent, allow a thick layer to be applied over the repair in only one or two coats. After a half-hour of drying the primer is ready for sanding.

(Warning! Before applying any primer or paint, be sure to wear a respirator rated for organic solvents.)

Step 5: Contrast Paint the Primer/Surfacer

Before you sand, apply a light mist of black lacquer from a spray can over the repaired area. This contrast coating will reveal imperfections that will disappear as you sand. Make sure there is adequate ventilation, and also make sure that pilot lights and other flame sources in the general area are turned off.

Step 6: Prep for Paint

To sand the primer, use a rubber sanding block and 400-grit waterproof sand paper. The trick is to sand lightly while frequently dipping the paper in a bucket of water to keep it clean. When all of the black contrast coat has disappeared, the repaired area is finished. Then clean and prepare the surface surrounding the repair to accept paint then wipe the entire panel with a solvent-based wax remover. Now, wetsand the area again to be painted with 600-grit waterproof sandpaper. If you're going to blend the paint into the original paint, make sure to sand an area larger than the area where you will be applying the paint. Thoroughly rinse the area, let it dry and then wipe again with wax remover. Mask off adjacent panels, then cover nearby wheels and major portions of the car with painter's plastic sheeting to shield it from overspray.

Step 7: Paint

Mix the basecoat with the appropriate amount and type of solvent according to the maker's instructions. Before spraying, gently wipe the area to be painted with a tack rag, then spray the panel or repaired area. If you are blending, apply only enough basecoat to cover the repaired area, then taper off as you move away from the repair. After the basecoat has dried thoroughly, you'll notice its finish is quite dull. This is so the clearcoat will adhere tightly. Do not sand the basecoat before applying the clearcoat. After mixing the clearcoat with hardener, according to the manufacturer's instructions, apply a medium wet coat and let it flash dry 5 minutes or so before applying a second coat. After letting the clearcoat dry for an hour, remove all masking tape. Then wait one day before polishing.

Step 8: Polish

Chances are the finish already looks pretty good. But to make it flawless, it pays to color-sand and polish the entire repair. Use 1500-grit sandpaper to flatten the finish, followed by rubbing compound to remove the scratches left by the sandpaper. Finish up with polishing compound to make the finish flawless. After polishing, wait one month to apply wax.



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    42 Discussions

    keep in mind that a body shop will charge you hundreds to do this. personally, I hate bondo with a passion, when it ages, it will get deformed, warp, chip, and eventually fall off. if you're going to do a job, do it right, by cutting out the dent, welding in a new patch, and sanding it smooth, then proceed from step 4. it's much more difficult, and risky, but it will last forever.

    1 reply

    I know this instructable is old and all but did you try just pushing it out with the butt of your hand. Has worked for me in the past. Of course the damage done by the wife taking the gate post to work with her might take a little more. Thanks a lot fella nicely done ible

    Lacquer is a transparent top coat that seals the paint underneath from the outside world and often uses u.v. inhibitors to make it last longer. It can also be tinted (coloured) with different colours to add to paint effects and is the reason why metal flek paint is so pretty.
    I hope this helps

    If the paint is not marred, use a dry ice to remove the dent instead.


    I thought this was about "taking out little chicks" ! You know, for dinner or a drink! Oops!

    Good write up, however this was really excessive. If you want to remove a dent like this all you have to do is get a toilet plunger and some water, wet both the plunger and the surface, put the plunger over the dent and quickly pull out. Voila, easy and can be done in 5 minutes, this seems really excessive.

    1 reply

    Harbor Freight tools is gawd in the eyes a budget DIYer.

    I used an angle grinder too (just like this illustration) I changed it into a buffing pad, the rev was too fast; burnt the paint.

    Hey, some folks are loving in the care they give to their cars, others aren't. I sit in the garage for hours every now and then touching up and making repairs to keep it looking new, and I've got an '04 Civic. Nothing fancy, but it's still something you adore. I loved this write-up. Laid it out very nicely and will help me solve that ding I have on my rear right panel.

    A paintless dent repair guy could make that look almost new for about $150. I've become a believer!

    I found the entire write up informative and made it seem a lot easier that I thought it was going to be. It seems as though it's about 90% prep and 10% paint. Thanks. I'm going to try this.

    It's best to use a matt black paint from a can, not a gloss. Gloss will clog your sandpaper when you try to sand it back...

    1 reply

    You can sand dome rubber when it gets clogged.Credit to TimAnderson for the idea of sanding rubber.

    Yeah, do it yourself as long as you have all of those professional tools.

    1 reply

    Thank you this will be a big help as my car was peppered by hail the night I went to pick it up and it wasn't insured...