How to Fix Rust On A Car

Have you been searching for how to fix rust on a car? Do you want to know the exact steps to take to keep your car rust-free?

Rust is a common problem in cars and can cause major damage if left untreated. In this post, we’ll show you how to identify and fix rust on your car. We’ll also discuss some of the most effective ways to prevent rust from forming in the first place.

So if your car is starting to show signs of rust, don’t wait – read on for tips that will help keep your car looking great!

Why Do Cars Rust?

If you want to know how to fix rust on a car, you need to know what causes it in the first place. Rust is practically impossible to avoid because it is a natural, electrochemical breakdown caused by oxidation. 

This chemical process occurs when iron – a core component of steel – or any iron-based bare metal comes in direct contact with oxygen and moisture. 

Or, to be more precise, it involves iron surface molecules reacting with oxygen in the environment – which is often moist – leading to the production of a brand-new molecule known as iron oxide, Fe₂O₃. 

This iron oxide is the rust you see on all iron-based metals.

But then, some types of steel take much longer to corrode than others. And today’s vehicles are produced with highly durable and heavily galvanized, corrosion-resistant steel or material. 

Factors That Contribute To Rust Formation

Most of the poorly-made vehicles manufactured in the ’70s showed surface rust almost as soon as they landed on the docks. And this was attributed to untreated raw sheet steel, which can easily rust within a few years. 

Several factors contribute to the rust of exposed steel, and these include:

• Alloy components
• The thickness of the steel
• The environment in which steel lives
• The type of heat treatment the steel undergoes

Moreover, road salt and other impurities are contributing factors since they become electrolytes when dissolved in water. The introduction of electrolytes into most chemical reactions leads to the acceleration of the exchange of molecular components.

This means that any salty or dirty water that gets trapped in one way or another in the vehicle’s body makes that area start rusting even faster. 

Pure iron does not oxidize as aggressively as some iron-based metals. But it is quite unfortunate that iron alone can’t be used for building vehicles. And that is why most vehicles today use steel alloys. 

When you add a dollop of carbon to pure iron, the result is steel which provides significant tensile strength, formability, and flexibility. 

The paint on your vehicle also plays a crucial role in preventing the onset of the iron worm. It works by physically preventing water and oxygen from coming in direct contact with the steel used in constructing the vehicle. 

Most modern vehicles hold up exceptionally well in the face of rust, especially if you wax your car from time to time. 

However, if you want to fix up an old vehicle or a car that has accumulated rust as a result of getting exposed to the elements for months, there are a few ways you can easily repair the corrosion without necessarily replacing the steel wholesale.

Types of Rust and How to Fix Them

Before you learn how to fix rust on a car or how to repair rust on your at home, it is essential that you know the different types of rust.

Rust typically forms in stages, and if you can identify the precise problem area where that decomposition process is, you will know how to apply the right solution. This means not all types of rust can be repaired with a car rust repair kit.

The following are the 3 primary stages of rust, as well as how you can fix them all:

• Surface Rust

In most cases, the first sign of a rust problem pops up in cracks, scratches, and paint nicks. Surface rust, as it implies, is the chemical reaction that occurs on the surface or body of your car,r especially the metal surfaces. 

Let’s say you park your automobile with steel disc brake rotors for a while. When you eventually check them, you will see the thin film of rust on the rotors. This is surface rust, which is not really a big threat as you can easily wipe it off the rotor after a few stops. 

Surface rust damage on vehicles forms when the paint breaks down via UV or mechanical damage. This is the primary reason why most cars – even in warm, dry climates – get surface rust. 

This type of rust is not really a problem, from a structural point of view, though this depends significantly on the metal’s alloy composition and thickness. In fact, there is a high level of passivation that can even be reached such that the surface rust prevents the bare metal from further oxidation.

Nevertheless, you should always correct surface rust as soon as you spot it. This type of fix may involve a general paint repair. 

• Scale 

If any rust forms on the surface and you do nothing about it, the decomposition will penetrate further into the metal. This is easily done since the chemical process corrupts the surface of the car, thereby reducing the strength of the metal.

The next thing you will start seeing are bubbles as they form in your vehicle’s paint. Iron oxide molecules form bubbles as they get larger physically than steel or iron molecules. 

This rust self-propagates by expanding and then flaking away from the exterior layers of metal and paint. This exposes the fresh base bare metal, which starts to rust.

Rust that penetrates your car surface causes a pitted and rough type of damage known as ‘scale.’ To correct scale implies getting through the rust with a wire brush. You can also knock down roughness via the use of a grinding wheel or smooth out your car surface using sandpaper.

• Penetrating

The prolonged exposure of steel results in its conversion to brittle iron oxide, which causes holes to form in your vehicle’s body. This happens when you allow rust to eat, unchecked, through your vehicle’s metal. 

This is known as penetrating rust, and it is the primary cause of the Swiss cheese-style holes you see in fenders as well as more dangerous issues, including weakened suspension components and frames.

Do you live in a region with rust-prone conditions? If you do, you don’t have to wait until bubbles start appearing in your car’s paint. 

You should also make it a habit to check the underside of your vehicle at least once a month. This will enable you to see if any compromised or rough parts may be considered a safety risk on the road if not fixed on time.

When scale rust worsens, it flakes away from the base metal, thereby leaving holes. And this is the biggest problem you have to face with only 2 options for you:

• Replace the affected panel or part completely (which is pretty tough and costly)
• Cut out the rusting parts and weld patch the affected panel or metal into place (which is tougher and costlier). This is the better option if the rust is a bodywork issue.

This is not something you can handle at home if you are only interested in how to fix rust on a car at home. But who can fix rust on a car, you ask? Well, you may have to search for a highly reputable body shop in your area that can take care of this rust problem for you. 

Don’t be tempted to repair large holes caused by rust with body filler. If the car frame is rusted through, it implies the overall structural integrity of your car is highly questionable, and using a body filler will do no good. But can you fix rust on a car frame? 

Unfortunately, you can’t unless you work in a repair shop. If not, make sure your car is inspected thoroughly and repaired by a certified repair facility. Don’t leave this to chance – check for signs of wear on the underside of your car from time to time before it becomes too late.

How to Stop Rust from Forming

It will interest you to know that you can actually prevent this type of vehicular decay. And the proper way to go about it is by washing your car regularly in order to keep the entire body as well as its underside clean of dirt, salts, and road grime that cause corrosion leading to rust on cars.

In most cases, car washes can readily blast the underside of your vehicle with clean, fresh water in order to get most of the debris and grime off. And when washing your car, make sure you blast water right behind the tires where lots of road gunk accumulates. 

Leaving road gunk in these areas can easily lead to the abrasion of rust-resistant coatings. Check the lower door corners since they are often susceptible to car rust.

The second-best advice you can follow to prevent rust from forming involves checking the drain holes arranged along the bottoms of the rocker panel and doors. These drain holes were originally designed to allow rainwater to flow out during heavy rains. 

Get a pipe cleaner that you can use to clear out these holes while ensuring your car’s nooks and crannies are always dry so that even the common rust spots are covered.

How Much Does It Cost to Fix Rust on a Car?

So, how much does it cost to fix rust on a car, you ask? The truth is that rust repair can cost anything from $20 to $2000 or even more. However, this depends primarily on the extent of damage caused by rust, as well as how thoroughly you want to fix it. 

You can have body shop technicians carry out an evaluation so they can give you a proper estimate for the job depending on the level of rust. Extensive rust will definitely cost more than mild rust. 

It is therefore advisable that once you see any signs of rust you should take action and have it fixed before it becomes full-blown rust.

Car Rust Repair Kit Available

Several car rust repair kits are on the market today that can be used for your rust repair job. However, you need to be careful so that you don’t end up with one that makes matters worse.

You can select the most suitable car rust repair kit or rust inhibitor by going online and reading the reviews left by those who used one on their rust-infested vehicles. The one that has the most favorable reviews is the car rust repair kit to go for.

You can also ask for recommendations from friends or colleagues who have repaired car rust the moment you spot signs of rust.

Step by Step Guide On How to Remove Rust from A Car

Before removing rust from your car, make sure you have the basic tools and wear a pair of gloves, a dust mask, and safety glasses.

1. Use ‘Filler Patches’

Step 1: Get and use a metal grinder to get rid of all the rust. Stop only when you see un-rusted or fresh steel all around the region where the rust spot was.

Step 2: If the rust leaves a hole, apply a commercial filler – such as Bondo – over the former rust spot. If the hole is somewhat large, you may need to improvise a little using a material that paint can bind to easily. You can cut up soda or beer cans for the hole-patching process. You may also go for thin sheets of hard plastic, which is also resistant to corrosion.

Step 3: Fix the material over the hole with a coat of filler and leave it until it gets dry.

Step 4: Use sandpaper to create an even and smooth surface or nice finish between this brand-new patch and the body of your car. This can be a tedious process.

And as you keep sanding that spot with a sanding block, you may need additional filler. Apply it to the spot and leave it long enough to get dry before you sand it away. In other words, follow this process: apply filler, grind with sandpaper, filler again, grind away again, etc.

Start the grinding with low grit sandpaper in order to smoothen out big bumps. Then transition to a medium – and then – a high grit or fine sandpaper for a smooth finish.

Step 5: Mask most of the car in order to protect most of the car from epoxy primer paint as well as other airborne particles. Don’t leave out your tires and windows. This is vital since you need to apply a fresh coating to the newly repaired rust spot.

Step 6: Apply a thin coat of self-etching epoxy primer and give it enough time to adhere before re-applying on top of it. Allow the primer to dry overnight and then give it a wet sanding with wet 400-grit sandpaper after approximately 12 hours.

Apply the paint on top by spraying a thin coat, allowing it to dry, and re-apply again, just as you did with the epoxy primer. You do not want to apply paint over rust- this will not solve the problem.

2. Buffing and Re-painting Rust Spots

Step 1: Put on your safety gear to prevent injuries.

Step 2: Since paint and rust particles will be up in the air, mask those parts of your car you are not really working on using masking paper and tape. Don’t use newspaper because spray paint chips can leak through, thereby leaving unsightly specks. Use a real masking paper that is less porous and never allows paint through

Step 3: Make sure you have masked the proper places correctly in order to prevent sharp lines where old paint begins, and new paint ends.

Step 4: Get a dual-action or DA sander to get rid of the pain around the rust damage. This sander enables you to control the speed of the sander as you remove the paint.

Start with 40-grit sandpaper then proceed to an 80-grit sander and work your way up slowly to 150 grit to take off the paint and primer. Use to remove any light rust that is yet to fuse with the metal.

Step 5: Get a metal grinder to get rid of thick rust buildups and expose existing pits. Be careful when using this tool so that it doesn’t damage your car’s body.

Step 6: Apply rust-removing acid – e.g. phosphoric acid, etc. – to the area in order to remove all microscopic rust particles there.

Step 7: Get a primer that is perfect for painting on bare metal, as well as an auto spray that matches the overall color of your vehicle. You can buy these at the local auto supply store.

Step 8: Spray up to 3 coats of primer, and wait for some time between coats so that it dries completely before the next application. Do not over-apply. You may have to leave up to 12 hours for the primer to dry.

Step 9: Sand using 320-Grit sandpaper that is wet, because it is designed for sanding between paint coats in order to smoothen the surface and de-gloss. This allows the paint to bond without any problem.

Rinse the sandpaper from time to time from a bucket of water so that it doesn’t foul up the paint. Wash the freshly painted area with light soap and water when you finish. You can then proceed to higher 1,000-Grit sandpaper, which is fine-grit sandpaper for a finer finish.

Step 10: Spray the area with thin coats of paint and allow the coat to rest for a few minutes in-between applications. This prevents the paint from running or sagging. 

You can use as many coats of paints over the primer so that you can get a nice finish and color. Allow the paint to rest for 24 hours, max before you pull off the paint. Give it more time if the paint still feels somewhat tacky.

Step 11: Apply a clear coat to match the finish on the other parts of your vehicle. Then allow the paint job to cure for at least 48 hours.

Step 12: Wash and polish your vehicle with a clean cloth or microfibre cloth. But don’t wax fresh paint within 30 days of painting as the buffing and scrubbing action during polishing may pull off the fresh paint job.

Conclusion

The goal is to ensure that your car metal is always properly sealed from the elements via the use of durable paints. And you must ensure that your vehicle remains free of grime and corrosive salt. 

If you can do this, you will get several years of safe driving out of any vehicle, no matter how weather-beaten or abused by the winter the car is.

By now, it is believed that you have learned how to fix rust on a car at home as well as when and where you need to apply the car rust repair kit.