Cars/Motorcycles, Repairs

How to fix rust on a car: expert methods and tips

Scratch on fender

Image via: Pexels

Sure, you can reduce the risk of rust and rust marks on your vehicle by applying a paint protection film to high-risk areas, such as a paint job. For example, apply care to the front edge of the hood, and wash off road salt regularly and wax your vehicle regularly. But even then you will still get rust stains. This is how to fix rust on a car.

Fix rust on a car: the process and materials

To fix rust on a car is not difficult, but it is time consuming (usually wait until the primer and paint dry between the steps). Plan to spend about $ 100 on supplies such as sandpaper, primer, masking tape, and poly-film, a staple residue, polish, and touch-up paint and clearcoat. Choose a calm, cloudy day and block all day to fix the most common rust spots on the bonnet and doors.

You can buy car paint in pint and quartz to use in a spray gun in aerosol cans or rollerball applicators. Even if you know how to use a spray gun, mixing car paint with a reducer to meet temperature and humidity conditions can be very difficult. We do not recommend it. Instead, you should buy aerosol cans for larger repairs and rollerball applicators for scratch repair when you fix rust on a car.

To find the perfect color match for the factory livery of your vehicle, you must first find the paint code. It can be in a variety of places on the body, in the engine compartment or trunk or in other places. Use one of the following online resources for instructions on finding your color code: or

Most older vehicles were painted with basecoat / clearcoat. The base coat contains only the pigment and binder resins – the clear coat is only the gloss. You will need equal amounts of both. You also need a self-etching epoxy primer to bite into the bare metal and a paint primer to hold the paint. You can buy car paint locally from a professional body supplier.

Next, buy 40-, 600- and 1000-grit sandpaper, a sanding block, grease and wax remover, polyfoil, painter’s tape, a squeegee and a microfiber cloth.

The steps

Step 1: Mask the repair area

  • Protect the entire vehicle from paint fog with drop sheets.
  • When painting the bonnet, spread the sheets over the engine and mudguard.
  • In the door areas, cut poly foil sheets to fit the door opening and glue it to the post.
  • The last cover must be one or two feet from the repair area so you have room to mix the touch-up paint into the good areas.

Step 2: Remove the rust

  • Crack off all of the blistered paint with a scraper.
  • Then grind the grate with 40 grit sandpaper and grind through the rusty spots to the bare metal.
  • Then enlarge the ground area so that you have enough space for the edges.
  • Then stain the edges with 120 grit sandpaper.
  • Complete the suspension with 220 grit.
  • If the rust has formed pits in the metal, you can now fill them with body filler or wait for the epoxy primer to dry and apply several coats of primer.

Step 3: Clean with detergent

  • Clean the entire unmasked area with a degreasing dishwashing detergent followed by clean rinse water. Let it dry.
  • Then wipe the area again with a lint-free cloth to remove dust and lint.
  • Apply preparation solvent of the paint manufacturer.

Step 4: the primer

  • Epoxy primer, then apply primer.
  • Spray the filler in thicker layers to cover the entire repair area.
  • Move the can slightly away from the surface and mix it into the surrounding area. Self-etching epoxy primer provides a strong bond with bare metal. Use it as the first layer.
  • Spray two or three medium coats with the recommended waiting time (usually 15 minutes) between coats.
  • Wait a full hour for the epoxy to feel (longer if wet outside).
  • Sand the epoxy primer with 1000 grit wet sandpaper.
  • Wash with clear water and leave to dry.
  • Wipe the dried epoxy primer with a lint-free cloth and apply two to three heavier paint filler coats, allowing for drying time between coats.
  • Allow the primer to dry until it is dry for at least one hour before sanding.

Step 5: Sand the primer

  • Sand drips and sags with 320 grit sandpaper.
  • Then grind off the entire repair area. Start with 600-grit wet sandpaper, flatten the primer, and feather the edges.
  • Then switch to 1,000 grit wet sandpaper to grind the entire repair, including blending surfaces.

Step 6: Spray the base coat

  • Apply the colored base coat. Start at the end of the repair and apply the color coat in rows from left to right, overlapping each run by about a third.
  • Apply the paint slowly in two or three coats to the repair and ambient, leaving between coats for about 10 to 15 minutes.
  • Keep the spray can about 12 inches from the surface, spray the repaired area.
  • The slower you build up the paint, the better it will look under the clearcoat.
  • Allow the base coat to dry for at least 60 minutes until dry.
  • Do not sand the primer (especially metallic paints) unless you have created sags. In this case sand lightly and then repaint the repair points.

Step 7: Spray clear coat

  • Apply several coats of clear lacquer, observing the recommended drying time between coats.
  • Gradually incorporate the clearcoat into the surrounding paint areas to achieve a smooth progression line. This is the hardest part because all clearcoats run smoothly and ruin the look of your paint job. If you make a run in clear coat, you must allow it to dry for at least 48 hours before fixing it with fine sandpaper and polish. Then you have to spray the sanded area again. So practice spraying on a piece of cardboard to get a feel for the nozzle and the speed of application.
  • Clean the painted area one last time with a rag.
  • Then apply the first clear coat so that it looks wet.
  • Allow the clearcoat to dry for at least 48 hours and at least 48 hours before polishing.
  • Polish the repair: Use an old cotton T-shirt or microfibre cloth and polish to hand-polish the repaired area. Do not use a polishing machine for this step.
  • Wait at least 30 days before waxing.