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How do you treat rust on a car?

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Treating any signs of rust as soon as possible will halt the spread and the risk of long-term damage to your cars body, undercarriage or any metal parts. To treat rust on a car you will first need to determine whether it is just minor and in an isolated area or whether it is more severe with larger areas of your car affected.

Familiar places you are likely to see rust are the wheel arches, bumper and around the windscreen. Lets not forget about the undercarriage too.

There two methods used to treat rust on a car. Rust can be eliminated using a mechanical method, by chemical intervention or a combination of both. 

Follow these important steps to treat rust to the undercarriage

  1. Pressure wash your car thoroughly. This should include the chassis, all cavities and box sections as these are areas where salt, mud and muck can accumulate therefore you want to ensure all traces are removed.
  2. Get car up onto a ramp or jack it up to inspect under the chassis.
  3. If you can get hold of a steam cleaner, then this is ideal for removing all traces of grease from the chassis area and all associated components. Grease could hinder the full effect of rust proofing.
  4. Leave car for a couple of days to fully dry out.
  5. Inspect for areas of rust. 
  6. Look for any structural damage due to rust. For severe structural damage to a metal part it will need removing and replacing.
  7. Apply a rust converter to treat rust. This will convert rust to a stable inorganic compound which is over paintable.
  8. Apply rust converter inside chassis cavities. Apply to any corroded surfaces. Use a lance to get inside all cavities areas.
  9. Rust proof the underbody by applying a cavity and underbody wax to all box sections, cavities and chassis using a lance to ensure all areas get a good coating - wear protective clothing, disposable gloves and a face mask as this job can get a little messy. 

The effectiveness of a rust converter is dependent on good surface preparation.

  • Remove excess flaky rust with a stiff bristled brush - this step is important but no need to scrape down to bare metal surface.
  • Clean and de-grease the surface - remove all traces of contaminant such as road salt which may interfere with the action of the rust converter.
  • Leave surface to dry thoroughly.
  • Apply the rust converter and leave it to cure for a day.
  • Apply a primer and paint.

Treat rust to the body of a car

For heavy rust to areas such as the wheel arches this is best treated first by mechanical means. For small isolated signs of corrosion to a stone chip, this can by treated by applying a rust remover and over painting.

  1. Wash car thoroughly and leave to dry-off.
  2. Tape off areas of your cars upper body that won't be treated such as windscreen, side mirrors, head lights - this is to protect from an over spray. Use tape and poly-sheets. 
  3. For crusty surface rust use an angle grinder to sand down the rust right done to bare metal.
  4. Sand away as much of the rust as possible. Use a course grit sander - 80 grit to start and 200 - 400 to feather the edges. The fine sander is also used to smooth out the course sanding scratches.
  5. Apply a rust remover to tackle any light films of corrosion left after sandblasting. This step will help make sure you fully treat rust. The oxalic acid reacts with iron oxide (rust) causing it to separate away from the metal surface. Once the rust has disappeared you are left with a stable surface for priming and painting.
  6. Check for any pitted areas to the body of your car. For a professional looking finish use an auto-body filler to smooth these out. 
  7. Coat the sanded area with a primer - aerosol or if you have a compressor you can use a gun applicator.
  8. Paint - spray on a base coat followed by a clear coat for added protection.
  9. Apply a cavity wax rust proofing. 

We hope you have found these steps to treat rust on your car of help. The best advise though is to prevent rust taking hold of your car by spotting it early enough. Corrosion can start in small chips and scratches to the paintwork caused by flying stones or minor impact damage. Such damage is easy to spot and treat provided you regularly cast an examining eye over the body work. The more difficult rust spotting places on a car are where panels join together and the undercarriage so don't forget those areas.

Rejel supply rust proofing kits to both treat rust and protect all size vehicles from corrosion. 

Classic Land Rover Rust Proofing Kit to treat rust and then rust proof to prevent further corrosion

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