How to Fix Rust Spots on a Car




About: Developing projects for HowToons @ Squid Labs.

I drive a 1985 VW Golf (diesel), and it's in pretty good condition for being 21 years old. There are three spots on the front left fender that have rust on them. Someone had hit the car and the paint came off, so it became rusty. These spots are not only an eye sore, but they are sure to spread in the salty Nebraska winters.

My goal in fixing these was function, and not so much glamour. The car is kind of a beater, so I wasn't too concerned with making it look perfect. As long as the rust was gone, it would look better, and I wouldn't lose a fender.

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Assess the Situation/ Remove Wheel

Having never done this, or any other body work on a car, it took me a little longer to figure out what exactly I was going to do. My original plan was to take the entire fender off, but after inspecting it, that would be too much of a hassle and would require me to disassemble a lot of the front of the car.

Instead, I jacked the car up then I pulled the wheel. I unscrewed the plastic thing protecting the wheel well and set it off to the side. That gave me really good access to see up behind the sheet metal on the car. I was originally going to pound out the dent on the upper part of the fender, but space was tight and I couldn't easily do it. Having the wheel well open will help when I'm grinding and painting.

Step 2: Remove Paint

The first thing I did was remove the paint around the rust. I used a 4 1/2" grinder with a 120 grit 3M Sandblaster wheel. It worked really well for taking off the thick layers of primer and paint. I carefully worked my way around the rust spots and removed paint until I could see clean metal surrounding the rust.

I also used that wheel for removing all of the light rust that hadn't pitted the metal.

Note: Before grinding, cover up anything that you don't want to get dusty. The paint dust is super fine and covers everything. I had my hood open to help access some rust, so I got a tarp to cover up the engine. Having your windows rolled down here would be a bad idea.

Step 3: Grind Some More

After I got all I could with the sanding wheel, I changed over to a metal grinding wheel. When using this, be super careful because these can do a lot of damage. I worked really slowly so that I could get a nice finish on the metal. It was really good for taking the thick rust off and getting into those pits.

After 99.9% of the rust was removed, I sanded by hand (with 120 grit 3M Sandblaster sandpaper) to get a nice smooth metal surface.

If I wanted, I could have used Bondo to even out some of the dents, and fill the space where the paint is gone

Step 4: Prep for Painting

I went to NAPA auto parts to find some primer and paint. I found some really good primer that is ideal for painting on bare metal: Dupli-Color Self-Etching Primer. Then I found some auto spray that matched the color of my car: Dupli-Color Auto Spray in Sunburst Gold Metallic.

I followed all of the instructions on the back of the primer: I mixed up a little bit of car wash soap and water and washed the areas that I was going to paint. Then I got a 400 grit wet sandpaper and sanded the areas, then wiped clean. I then masked off the areas with tape, and then taped newspapers on all the surrounding areas within at least three feet. Paint spray can get everywhere because it gets suspended in the air and blown around and settles somewhere. Once everything was masked off, I was ready to prime.

Step 5: Prime, Paint

When applying paint, it is important to spray thin coats and keep it even. The paint that I was using was really nice, and went on very smoothly. I ended up spraying three coats of primer, waiting about two minutes between each coat for it to tack up. I let that sit all night and sprayed the paint in the morning. I had to spray the paint on even thinner, because it really wanted to run and sag. I ended up having five coats of paint on top of the primer. That gave me a nice color and a nice finish. I let it set at least 24 hours before I pulled off the tape.

The paint turned out pretty well, and it just looked like little patches over the old rust. The color wasn't quite the same as the old, but it was pretty close. It also had no clear coat on it, so it had a little different finish. I didn't bother buffing the edge of the paint so that it blended with the old paint.

Step 6: Wash and Wax

After the paint had cured a good 48 hours, I washed and waxed the car to bring back the shine. It ended up looking fairly good. It cost me less than $15 and 4-6 hours of labor. I spent an additional 4 hours washing and waxing. If I had taken it to a body shop, it could have cost me $200. So I saved a lot of money and got the satisfaction of doing it myself, which is the best part.



    • Indoor Lighting Contest

      Indoor Lighting Contest
    • Metal Contest

      Metal Contest
    • Make It Fly Challenge

      Make It Fly Challenge

    103 Discussions


    5 weeks ago on Step 6

    A body shop in Minneapolis?? Would cost you more than $200 to drive in the door.


    Question 1 year ago on Step 3



    1 year ago

    I just want to say I'm jealous of your car. An early MK2 Westy is basically my dream car. Do you still have it?


    3 years ago

    For people looking for the right paint to use for their year/make/model:


    4 years ago on Introduction

    Lovely. I want to fix the rust spots on my car. This is a useful guide.


    4 years ago on Introduction

    I miss Earl Scheib! " I'm Earl Scheib, and I'll paint any car, any color for $19.95. No ups, no extras."


    4 years ago on Step 4

    Good Instructable. I've had a couple spots where paint chipped out and rust is occurring, each spot 1/2'-12mm< in diameter. I cut a circular hole in 2" wide tape, masked areas, just rust remover gel, wiped clean with alcohol. All the rust was gone. Touched up with epoxy primer, sanded lightly then used color match pens available at auto stores to repaint area. Removed tape lightly sanded with 800 grit to very gently feather new paint edge down. My areas super small, rust getting bigger my worry. Car 1999 so all the "glossiness" gone. Color is white and barely visible ... mainly because it's the clean spot! LOL

    Important part is getting all rust out and good base primer on like you did.


    4 years ago on Step 6

    Nice write-up, I'm doing the same thing, but can't get down clean metal in some spots. I'm going to try Eastwood Rust Encapsulator (a POR-15 product) and then factory matching paint from Harbor Freight also sells rust specific wheels that will remove paint and rust nicely, but not metal.


    4 years ago

    Could you please outline for me exactly what and what you have used and their prices thanks


    6 years ago on Step 4

    I've heard if you roll the tape in on itself around the area to be painted it will make a less harsh masking line. I'm taking out some rust on my car during a full top to bottom respray (an enormous undertaking). After cleaning using a wire brush on a drill, I'm treating the areas with rust killer then etch primer then regular primer. While Epoxy is the best primer to use on treated areas, it's a tough product to use for a beginner.


    6 years ago on Step 6

    i wish things were this easy for me, but i have 6 cancer spots were i had to cut metal out and tack in some new metal and bondo over it, i have a few spots of bubbling rust and of course nothing is in an easy spot


    6 years ago on Step 6

    i have a 96 golf that has a few rust spots, im thinking of doing this! it turned out really well.


    9 years ago on Introduction

    is there an acids that remove rust, i have a chainmail shirt that i need to de rust and it will that to long to polish every ring

    5 replies

    Reply 6 years ago on Introduction

    I know I am a couple of years late to this post. But....
    The best way to derust a chainmail shirt is to do it with electrolisis. You will need A car battery charger, Washing Soda, 1 12 inch or longer Piece steel rod, or rebar.
    In a 5 Gal bucket filled with watter put 1 cup of Washing Soda (not bicarbonate sodium), Mix thoroughly, Clamp the Positive side to the Steel rod, Clamp the Negative side to the ChainMail shirt, Drop it on the water, Hang the steel rod from the edge of the bucket making sure that it is close tho the chainmail but not touching. Turn on the charger and watch the rust go up in rusted bubble crust on top of the watter. Give it about six to eight hours.
    You are completely done.


    Reply 7 years ago on Introduction

    a non chemical way to remove the rust is to put the chainmail shirt into a sealable large container (5 gallon bucket with a lid is great for this) and add some fine sand (in a pinch you could use sifted playground sand) or other abrasive compound.

    put the lid on tight, turn the bucket on it's side, and roll the bucket to aggitate the shirt and the abrasive.

    after you get the shirt cleaned remove it from the bucket, clean it off, oil it well.


    Reply 9 years ago on Introduction

    There's also phosphoric acid; you should find some form of it in the auto body supplies section, maybe under a brand name like Ospho or metal prep. Citric acid also eats rust; you can get that in dry form at home brewing supply stores. And, finally, sulphated molasses, from the feed store. Google these things along with rust and you'll find more information.


    12 years ago on Step 3

    i was just wondering what to do if the rust is all the way through. can you use bondo for that? the spot is about 14 cm by 8 cm.

    1 reply

    Reply 6 years ago on Step 3

    For holes, you can use a backing material for Bondo to stick to. It is Bondo brand wire mesh that has self adhesive glue on back to keep it in place. You can use scissors to shape. Just follow instructions on the package. Prime and treat the back side of the patch if you can.