How to Get Rid of Rust on a Car

Rust is one of the scariest maladies to owners of classic cars. Once you see a glimpse of that red plague, you know you need to act fast or your pride and joy could literally start crumbling around you. Let Scrap Car Comparison guide you through everything you need to know on how to treat it before it gets too bad.

If you’re too late, however, and the rust is unsolvable, we’re also here to help you find the very best price possible for your car, whatever condition it’s in. Scrap Car Comparison scours the country to find unbeatable prices for broken, tired or simply unwanted cars, and if you’re at a loss for where to go, our advisors will be more than happy to guide you through the process.

How to treat rust on a car

The treatment for rust or corrosion on a car depends on how much there is and where it’s taken hold. If the rust is simply on the paintwork then it can be easily removed, whereas if the rust has taken hold on some more structural locations it is likely to be beyond your help and will require a professional’s touch.

If you have managed to catch the issue early, then you may be able to carry out repairs yourself without needing to pay an expert. Here’s a step-by-step guide on what to do:

Remove paint and rust: You could do this with coarse 80 grit sandpaper and a wire brush, but an angle grinder with a flapper wheel will do a much better job.

Repair the area: This is done using long-strand fibre repair gel – the reason for choosing this over body filler is the fibreglass will provide a much sturdier finish, almost as strong as steel. Once the gel has been mixed with the hardener it will begin to firm up within around 15 minutes.

Sand off excess gel: Using the angle grinder and flapper wheel, sand off any excess that has been pushed out through the holes – this should be doable within an hour from the point the gel is applied. 

Apply filler & hardener: Once the fibreglass has been sanded down, apply a mixture of body filler and hardener with a flexible, flat spreader and press it into the rust holes. Try and get this as flat as possible to avoid having to sand it down, while also avoiding any low spots or scratches that would require a second coat.

Sand it down: The most time-consuming part of rust work, sanding is also the most important part of the process as a bad job now will make the final paint job noticeably off. Beginning with a 400 or coarser grit sandpaper, remove any excess filler – this will be easier if it hasn’t fully hardened yet. 

Clean the area: Once the sanding is complete, clean the area with a rag and mineral spirits to remove any oil from your fingers. You should be able to see metal and paint through the bodywork, and once it has dried wipe it again with a tack cloth to remove any lint. Even a speck of dust can cause blemishes in the paint, so this needs to be absolutely spotless before continuing.

Prime the area: Apply a layer of primer to any bare metal with around an inch of overlap for blending. Begin with a thin coat, and then go over with a heavier layer once it has totally dried.

Sand it… again: Wet-sand the primed area until smooth and the edges feather into the original paint. Wipe it clean, allow it to dry and apply another layer of primer. Moving to a higher grade of sandpaper, repeat the process and prime again. This should take two or three repeats before you get a smooth enough repair.

Start painting: It is best to apply your paint in several thin coats as opposed to one thick coat as it will avoid drips or runs in the finish. 

Polish until glossy: If you made any mistakes such as runs or drips in the paint you will need to wet-sand these first. Be careful not to overdo this, however, as sanding too much will mean you’ll need to apply another coat of paint.

Can I treat rust on a car myself?

By following the above you should be able to achieve acceptable results, but if you’re not sure or convinced you’ll be able to carry these out satisfactorily, then taking it to a professional is a much simpler option – although does come with the additional costs. 

How to stop your car from rusting

While you might think that rust is a simple inevitability of owning an older car, it is only inevitable to those who don’t specifically treat their cars against it. 

Rinse & dry: Rinsing your car and drying it off can help clean out any dirt and grime that may have settled on your paintwork which could turn to rust. This is particularly important if you live by the sea.

Wax on: A coat of wax adds a protective layer to your paintwork and will stop moisture from affecting your bodywork.

Use water dispersants: Applying oil to your hinges, joints and hard-to-reach areas can prevent rust from forming in the difficult areas – using WD40 can be particularly useful, and did you know that the WD stands for ‘water dispersant’? It’s literally made for the job.

Park securely: Parking your car away from the elements, such as in a garage, can stop the weather from getting to it, and if you want to go one step further, using a dehumidifier within the garage ensures there’s even less moisture that can get to it.

Do modern cars rust?

Rust is more of an issue for older cars than newer ones, and that is in part because modern cars are made from lighter materials than the heavier metals previously used in automotive manufacturing. Not only that, plastics and carbon fibre both feature more regularly in new cars, neither of which are susceptible to rust in any way. Such is the rarity of rust these days that modern car manufacturers often offer rust protection plans for up to ten years – or in some cases even longer.

Can you fail your MOT due to rust?

Yes, if it is in sensitive areas that are important to the vehicle’s safe operation, rust will cause your car to fail its MOT test. This rust will need to be severe though, to the point that the structural integrity of the metal part in question would need to be lost. Surface rust only shouldn’t result in a test failure.

What types of rust do you get on a car?

There are three main types of rust that can appear on your vehicle. All of them have detrimental affects, but they also have different levels of severity:

Surface rust: This is the least severe type of rust, and the good news is, you’ve spotted it in its earliest stage. As the name implies, it only impacts the top-level of your car’s metalwork, mostly damaging the paintwork.

Scale rust: Scale rust is the next phase of the rusting process, where thicker plates of rust appear on the vehicle’s metalwork. At this point, the damage is beginning to spread into the metal, rather than simply making the top-level paintwork look nasty.

Penetrating rust: This is the rust that you don’t want to find on your car. It’s rust that has successfully managed to corrode the metal and damage the parts, usually beyond repair. You might find that smaller, lightweight metal components will start to literally fall apart! Typically, this type of rust will result in parts needing replacing.

Where can you expect to find rust on a car?

Rust can appear on any metalwork around the car. However, due to the closer proximity to the ground and the ease with which the area can become wet and grimy, the underneath and lower side areas of a vehicle are much more likely to suffer from rust damage. This is why it’s important to regularly inspect your car, particularly if you live in an area where it rains a lot or there’s a lot of moisture in the air.

Will painting over rust on a car stop it?

No, simply painting over it will not stop rust on a car from spreading and doing further, more serious damage to your vehicle. You would, effectively, be papering over the cracks. An ‘out of sight, out of mind’ thought process might work for some things, but with this, it’s not recommended.

Should I scrape rust off my car?

Technically, our guide above says that you should treat rust on a car by scraping or rubbing it off, but it’s vital that you remember to perform this procedure with car. If you go at it and start hacking away at chunks of rust willy-nilly, you’re going to be left with a terrible mess to clean up – which you will also be totally unprepared to do!

How much does rust repair cost?

The price tag for rust repair will depend on where the damage is and just how bad it is. Repairing it yourself will inevitably be cheaper, especially when you consider that body repair shops could charge up to £200 per hour, although the average is more like £60 for independent garages, while dealers and franchises are likely to charge closer to £100. This is all on top of the cost of materials, which will also need to be factored into your budget.

What causes rust on a car

Rust, plain and simple, is a chemical reaction that occurs when iron, oxygen and water combine. The oxidisation is visible as a reddish-brown coat and begins to corrode metal. This process can happen due to a combination of the material the car is made of, its age, the climate you drive in and the way you drive.

If you live in a location with greater-than-average rainfall, sleet or snow, then there is a much greater chance that the moisture will oxidise with the metal in your car. Likewise, salt and grit from roads can also help rust to appear. Higher temperatures also speed up corrosion.

As we’ve already touched on, older vehicles were made without rust protection in mind, which makes them far more susceptible to corrosion than newer vehicles, and if any of your metalwork is exposed through general wear and tear then rust is almost an inevitability. 

Finally, if you regularly drive off-road or make a habit of driving through puddles then you’re increasing your risk of corrosion substantially.

Get the best price with Scrap Car Comparison

If rust and corrosion are starting to take hold of your old set of wheels, then you might find that it’s beyond the realms of repairs, and scrapping or selling as salvage could well be the only realistic option that’s left open to you. By contacting the friendly team here at Scrap Car Comparison you’re guaranteeing that you’ll find the very best price possible for your vehicle. Not only that, we’ll even come and collect it from you at no extra cost, thanks to our nationwide network of specialist buyers and collectors.

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