Best rust proofing inhibitor spray for cars prevent & stop rust on car undercarriageunderbody, frame & scratches Review & buyer guide

Best rust proofing inhibitor spray for cars: prevent & stop rust on car undercarriage / underbody, frame & scratches | Review & buyer guide

Did you notice rust on the underbody, frame or other parts of your car? How can you stop, or even better, prevent the rust on your car?

Fortunately, there is an easy way to fix this. But the market is full of options and it is not easy to make the right pick.

Before you go to the solution, let’s define the problem.

What is rust?

Scientifically explained, rust is a red oxide or an iron oxide. So, in special conditions, the iron or steel reacts with oxygen and the material gets a reddish-brown color.

And why does this appears on a car?

Well, most car parts are made of iron and steel, but that is not the only reason. Several things can be the cause of it, and here are most of them.


Problem Cause Solution
Mud It can stick into inaccessible areas, like wheel arch lips, and it can stay there for a longer period of time. The mud keeps the place humid, which is perfect condition for rust.


Thoroughly wash your car and pay attention to the undercarriage
Stone chips Stone chips, or even a minor damage can be enough for rust forming on your car. Stone chips are hard to avoid, so the solution would be applying a protection wax for your paintwork
Salty roads In winter, most of the roads are salty. It is quite easier to drive because of it, but it has one big disadvantage – it can damage your car. Same as mud removal, you need to wash your car regularly
Drain holes If your drain holes are blocked, you are more likely to have rust on your car. These holes can clog after a while and are the first sign of corrosion. Check the drain holes, and always be sure that they are clear and water can go through them


Rust prevention

Is there a way to prevent rust on your car? Of course, there is. Don’t drive your car and that’s it.

Just kidding, pay close attention and you will learn the secrets of winning the battle against the rust.

Best rust prevention spray for cars

Evapo-Rust RB015 - Rating
PlastiKote Rust Converter - Rating
Rust-Oleum Rust Reformer - Rating
Corrosion Inhibitor - Rating
Rust-Oleum Automotive Rust Reformer - Rating
Corroseal Water-Based Rust Converter - Rating
CRC Corrosion Inhibitor - Rating
VHT Rust Convertor - Rating
Permatex Rust Treatment - Rating
Krylon Rust Tough - Rating
POR-15 Rust Preventive Paint - Rating
Rust Bullet Inhibitor Paint - Rating
BOESHIELD Rust&Corrosion Protection - Rating
Corrosion Technologies Max Wax - Rating

Since there are lots of sprays, it is easy to make a mistake and buy the wrong one. By the wrong spray, I mean spray that can damage your car paint, a spray that you can overpay for or it just won’t do the job.

In order to save you time and effort, I did a research on the market and reviewed the best sprays available.

Without any more hesitations, let’s jump in.

Evapo-Rust RB015

Using different chemicals can cause allergies or other skin problems. You will need to put on special gloves, and work really carefully in order to protect yourself.

Luckily, this cleaner has no acids, it is safe on skin, which makes it one of the best rust inhibitors on the market. If you have sensitive skin, this spray may be the best pick for you.

Evapo-Rust RB015 rust spray review

The Evapo-Rust RB015 rust spray

It is non-toxic and non-flammable and completely safe to use. It is budget-friendly, and you can check the current price of the Evapo-Rust RB015 here on Amazon.


  • no acids
  • biodegradable
  • safe on skin

PlastiKote Rust Converter

Just like the vinegar, there are many rust sprays on the market that can damage your car paint. Since rust is enough problem, you don’t want to re-paint your car, which is why you need to find a quality spray.

PlastiKote Rust Converter analysis

The PlastiKote Rust Converter

The PlastiKote Rust Converter will convert the rust to an iron-hard surface, that can be easily re-painted. However, it won’t cause bubbling or foaming which may be the case with many other cleaners. It is a high-quality rust spray that you definitively need to consider.

It doesn’t have hazardous chemicals that can damage the paint and it is the actual reason why many customers prefer this product.  Check the latest price of the PlastiKote Rust Converter here on Amazon.


  • easily converts rust to a paintable surface
  • no bubbling or foaming
  • no hazardous chemicals

Rust-Oleum Rust Reformer

After using some rust removal sprays you will need to use sandpaper on the metal. But not if you use the rust reformer.

Rust-Oleum Rust Reformer evaluation

The Rust-Oleum Rust Reformer

It reduces the need to sand the metal and converts the rust into a paintable surface. It can be primed, and it leaves a dark, durable finish.

Unlike many other models, you don’t need to pay much for this one. You can check current price and customer reviews of the Rust-Oleum Rust Reformer here on Amazon.


  • converts rust into a paintable surface
  • reduces the need to sand the metal
  • can be primed

Corrosion Inhibitor

Looking for a long lasting rust spray inhibitor? Take a look at this one.

It is solvent free, and will not dry out. It is eco-friendly and it won’t freeze no matter how cold temperatures are. This clean, lanolin based spray may be the right pick for you.

If you clean your car undercarriage and use this spray – you won’t notice any rust afterwards. Check the latest price and customer reviews of the Corrosion Inhibitor here on Amazon.


  • anti-freezing agent
  • lanolin based
  • long-lasting

Rust-Oleum Automotive Rust Reformer

When using rust removal sprays like these, sometimes you may need to wait for hours and even day to dry. But this one instantly converts the rust into a paintable surface.

Rust-Oleum Automotive Rust Reformer assessment

The Rust-Oleum Automotive Rust Reformer

Not only doe it deal with existing rust, but also prevents future rust forming. Plus, you won’t need to sand the metal which will save a lot of time and effort.

This spray offers quality protection and it is amongst the best on the market. Check the latest price of the Rust-Oleum Automotive Rust Reformer here on Amazon.


  • instantly converts rust to a paintable surface
  • prevents rust forming
  • there is no need to sand the metal

Corroseal Water-Based Rust Converter

This is one of the best, if not the best rust converter available on the market. Its formula is based on water, but it is still an effective way to deal with rust.

Corroseal Water-Based Rust Converter analysis

The Corroseal Water-Based Rust Converter

It doesn’t remove the rust, it converts rust. It is good not only for vehicles but also for households, industry and even marine equipment.

It is easy to apply, but also easy to clean it up – you will need just soap and water. Check customer reviews and ratings of the Corroseal Water-Based Rust Converter here on Amazon.


  • converts rust in one step
  • easy to apply and to clean
  • has many different applications

CRC Corrosion Inhibitor

Afraid that you can damage your chrome wheels with the spray? Not with this one for sure!

CRC 06026 Heavy Duty Corrosion Inhibitor comparison

The CRC 06026 Heavy Duty Corrosion Inhibitor

This inhibitor spray offers extended rust protection for different types of metals, and you don’t need to worry that it will damage your car.

It is very effective and it seals out moisture. Plus, it won’t freeze. You can check the latest price and customer reviews of the CRC Corrosion Inhibitor here on Amazon.


  • effective protection
  • extended corrosion protection
  • seals out moisture

VHT Rust Convertor

The easiest way to fight the rust – wash your car, and use this spray on the rusted areas.

This spray will convert the rust into black metal before you can even blink with your eyes. It is a thin liquid that dries very fast. In addition, it will prevent future rust forming.

Not every spray can show off with this as well – the convertor sands to a smooth finish and it is one of the best in its category. Check the latest price of the VHT Rust Convertor here on Amazon.


  • spray directly on rusted areas
  • converts the rust to black metal
  • prevents future rust forming

Permatex Rust Treatment

The most important thing you need to consider when looking for an anti-rust spray is the application, and this one is definitively easy to apply.

Permatex Rust Treatment review

The Permatex Rust Treatment

You can use a brush, or you can just spray it on rusted areas. It destroys the rust within several minutes, leaving a black metal. You don’t need a primer and you can paint it over it as soon as it dries completely.

Destroys rust on many different automotive applications, which is why you need to consider this one. Check current price and customer reviews of the Permatex Rust Treatment here on Amazon.


  • easy to apply
  • destroys rust very fast
  • the coating formed can be a great primer

Krylon Rust Tough

If you still didn’t find your favorite, this Krylon spray is something you must consider. Once it is applied, you don’t need a primer and can paint over it as soon as it dries.

Krylon Rust Tough assessment

The Krylon Rust Tough

And it dries pretty fast – for after 30 minutes you can apply the paint, which is something you can’t say for most of the sprays. However, the spray doesn’t fade away and it offers future rust prevention.

It has an affordable price. Check the current price of the Krylon Rust Tough here on Amazon.


  • you don’t need a primer
  • offers future rust prevention
  • dries very fast
  • long-lasting protection

POR-15 Rust Preventive Paint

Many of you may prefer a different way of protection applying, which is not bad, as you can find many great products that come in a can as well.

POR-15 Rust Preventive Paint analysis

The POR-15 Rust Preventive Paint

This is a great example for that – it is a coating designed for direct application on rusted metal. It has a black color, and it prevents rust from future recurring.

It is more expensive than other products, but the package is bigger too so it is suitable for big jobs. You can check the latest price and customer reviews of the POR-15 Rust Preventive Paint here on Amazon.


  • high-performance rust prevention coating
  • prevents rust recurring
  • application directly on a rusted metal

Rust Bullet Inhibitor Paint

The efforts of the Rust Bullet team resulted in this amazing rust protecting product with metallic gray color.

Rust Bullet Inhibitor Paint review

The Rust Bullet Inhibitor Paint

Unlike other similar products, this one can be applied directly to the rusted metal, and won’t fade or crack as it is UV resistant. There are different ways of applying it – use a brush, roll it or spray it.

It doesn’t require a topcoat, and the price for it depends on the size you want to buy. If you are interested in it, you can check customer reviews and ratings of the Rust Bullet Inhibitor Paint here on Amazon.


  • the application won’t fade or crack
  • no top coat needed
  • you can brush, roll or spray on

BOESHIELD Rust & Corrosion Protection

Imagine if you could have a rust protection that can be used not just for your car, but also for bicycles, tools, aviation, and marine.

BOESHIELD Rust & Corrosion Protection comparison

The BOESHIELD Rust & Corrosion Protection

Luckily, you don’t have to imagine as this inhibitor requires a tiny layer to flush the dirt out and protect the material from rust.  It was first developed for aircraft parts lubing but works on cars just as well.

It is safe to use on different metal surfaces and it is one of the best products available. Check current price and customer reviews of the BOESHIELD Rust&Corrosion Protection here on Amazon.


  • great for cars, bicycles, marine tools, aviation
  • safe on paints and different metal surfaces
  • just a thin layer can be enough to protect the metal for months

Corrosion Technologies Max Wax

Since it was regarded as the “best of the best” title by Field&Stream magazine, it deserves a place on our list.

Corrosion Technologies Max Wax review

The Corrosion Technologies Max Wax

Max Wax is a tough, synthetic wax inhibitor for long-term protection of metal surfaces. The best part? It won’t crack on freezing temperatures and even a thin layer will prevent rust forming for several months.

This wax forms a smooth coating, offering maximum protection and you can find it at an affordable price. If you like it, you can check the current price of the Corrosion Technologies Max Wax here on Amazon.


  • “best of the best” title
  • ideal for long-term protection
  • it won’t crack on extra cold weather conditions

Which product do you find the best? Feel free to share your opinion and experience in the comments below.

How to stop rust from spreading on a car?

Recently, there is a lot of debate on this topic. If you start searching for automotive forums, you will find many different answers.

As a newbie, you may go for the wrong ones. However, here is what you can expect and what you can trust.

Mechanic gurus will suggest you use rust spray for cars, which is the answer you need to consider. However, there are other opinions as well.

Some ‘experts’ confidently say that using this kind of spray is basically a waste of money. Their biggest argument is that cars are already protected and just washing your car will be enough to prevent rust on it.

However, I highly disagree with this.

This can be true under only one condition – If you live in Florida, or other places with nearly same weather seasons (definitely no snow).

You drive your car rarely and you can afford to buy a new one after 2 or 3 years. In this case you could probably do without rust protection.


Otherwise, using this logic that cars don’t need rust proofing is non-sense. If you don’t believe it, try it on your own and you will see what will happen to your car (hint – it will get rusty after a while).

But what if you live in an area where most of the time there is snow on the streets?

Now we are asking real questions. Is it enough to wash your car with water and soap?

The main weapon against snow on the streets is the salt. That is basically magnesium or calcium chloride, that is thrown on the roads many times over the year.

It is a great way of dealing with the snow, but it can leave permanent damage on your car.

These chemicals form a crystalline film on the car body and on the windows as well, which is very hard to remove with just water. If not treated properly, the crystalline film will stay on your car even when the winter season is over.

The rust eats the metal, and not only that, your car won’t look good, but it will be damaged that much that you won’t even be able to drive it.

Since you don’t want that to happen, you need a solution for this problem. Next section is a proof that you shouldn’t believe everything and contact professionals before you can start doing anything.

Does vinegar neutralize road salt?

If you don’t like spending money for sprays, you may start looking for other cheaper ways of dealing with rust. Vinegar, baking soda, or any homemade road salt neutralizer made of cooking ingredients is what people try to use to fight the rust.

Using any of these can be a good solution if you want to throw your car away and never get into it again. Seriously, sometimes it is better to pay for the solution rather than create a bigger problem.

Cleaning with a vinegar is a huge mistake as you can damage the paint with it. In order to find a cheaper option, you will make even more damage than not cleaning the rust at all.

Even the modern cars are not privileged

Another mistake is that new models don’t have this problem, as they have rust protection. They may need longer time to create rust, but modern cars are not immune to this issue either.

When you buy a brand new vehicle, you can choose to ask the dealership to apply a protection or do that on your own. Whatever you choose, keep in mind that the protection won’t last forever.

Luckily, there is a way to prevent rust formation. So if your goal is to keep your car for several years, no need to worry – just keep reading and you will find the solution.

How to prevent rust on a car?

Following these simple steps, you will be able to give your car a maximum protection. With regular maintenance, your car will be constantly in a good condition.

Firstly, you need to understand that the inside of the car is as important as the outside of it. The possibility that someone will see the inside of your car is down to a minimum, but that doesn’t mean that you don’t need to take care of it.

What is needed for rust forming?

Nothing much, just water and steel/iron. In order to protect your car, you need to find a way to protect the water to come in an interaction with the steel.

An anti-corrosion spray wax is one great way to prevent it. You need to insert the wax on the doors, trunk, frame, hood and so on.

It will block the water from interacting with the steel and forming a rust.

Secondly, you will need to take care of the underbody.

Most people don’t pay much attention to this, but it is also important as rust can form there too, mostly on the brake lines or the floorboards.

So, in order to prevent rust formation, you need a coating, as just a water wash won’t help you much.

Next, you need to maintain the paint. If you notice any minor scratch on your car, treat it as soon as you can.

Car scratch leaves the metal exposed

And again, I am not talking about the outside, the eye-catchy look of the car, even though I guess you wouldn’t like your car with scratches too.

The paint has another role and that is protecting the car from rust forming. So, whenever you scratch your car, do what it requires to re-paint it.

And finally, wash your car. The last step, but not the least important. It may be stupid to tell you this, but many people forget about this step, even though it is crucial.

Wash it frequently and thoroughly, clean all the dust and mud, and go under your car as well. Don’t forget the underbody as that is where the rust is most likely to form.

As frequent washing can damage the paint, use a professional car wash soap (like the Chemical Guys CWS_301 Citrus Wash and Gloss Concentrated)– since you are washing it frequently, it won’t be too dirty.

Rust is feeding itself with metal

Since you are aware of this, you need to find a way to stop that. Following these straightforward steps, you will be able to prevent rust on your car, use it for more than 2-3 years and increase its value if you are thinking of selling it.

How much rust is enough?

Well, my point is not to scare you, but even a small presence of rust should concern you.

People are often too lazy to take care of their vehicles and don’t really understand how serious this issue is.

Why is it important to prevent our cars from rust?

The truth is, your car is one of the biggest asset you own, of course, after your home if you own that.

You need to take care of it, no matter if it is old or brand new, you need to make sure that it is properly functioning. And believe me, rust is your biggest enemy.

The sooner you take care of it, the better. You can handle it on your own, or get it fixed by professional mechanics. Personally, I wouldn’t recommend you the second option.

Professional undercoating

The main reason why I disagree with finding a mechanic to fix this problem for you is that you will need to pay hundreds of dollars.

In case you can afford that and you are willing to pay for it, then do it. But, my point is that if you don’t want to spend a load of cash for it – here is how you can do it, or what the mechanic would do.

First of all, you need to access the underside of your car. You can place your car on a car hoist or use car ramps as a cheaper option. Then, clean the underside with a degreaser. Once you finish with this, use an angle grinder and remove the rust from the undercarriage. Just be careful and make sure your eyes are protected when doing this.

Most of the rust will be removed this way, but there will be some leftovers. Take some sandpaper for metal and sand anything left.

When sanding, you will leave some dust. Once you finish it, use a towel to wipe away the dust before you can continue to the next step.

Next step is prime and paint.

Prime all the areas that you cleaned the dust from. Leave it for a while to dry.

When it is dried, put the paint over the prime, and let it dry too.

Now, you have come to the last, but the most important step – applying the undercoating.

Apply the undercoating to every part that is exposed to the road. Leave it to dry for at least an hour, or even more.

When it is dry, apply a second coat. But, remember that you need to let the undercoating to dry for a day before you can drive the car.

It is best to use a rubberized coating as they are more durable, however, it is up to your choice.

How to remove a coating?

What if you want to remove the undercoating, so you can apply new? Well, this process is simple, you just need to apply removal spray, and when the coating is softened enough, just grab your scraper and remove it carefully.

Applying the protection

Applying the protective substance isn’t as easy as it looks. If you check my recommendations, you will easily notice that all of the products come in different packages.

So, how do you apply it?

The first category of products are the ones that come in a spray can. Once you finished the washing, take the spray and check every metal surface that you might think has rust formation.

Apply a thin layer of it on every area that has a rust on it. Wait for a while to let it dry and that’s it.

But what if you bought a different type of can? Well, nothing to worry about. Do the same as you would with the spray can, the only difference is that you will need a small brush.

Use the brush to apply a thin layer on the rusted metal and let it dry.

But, if we talk about wax application, things are a bit different.

First of all, clean the previous layer of wax. Wash your car thoroughly and make sure there is no wax left on it. Make sure the metal is completely dry before you continue to the next step.

Apply a thin layer of coat. You want to make your car shine, but you don’t need much wax. It is best to use a towel that is clean and dry before you use it.

Even one water drop can complicate this process, which is why you need to make sure that both the car and cloth are dry.

Repeat this process every month to keep your car in a perfect condition.

Rustproofing guns

As you may have noticed, some of the products are not in spray cans, but in a package that doesn’t allow you even to use a brush.

Best rustproofing gun

PMT Rustproofing Gun - Rating

Best value rustproofing gun

TCP Global Brand Pneumatic Air Undercoating Gun - Rating

Budget rustproofing gun

Astro 4538Economy Air Undercoat Gun - Rating

So, how do you apply these liquids?

Luckily, there is an alternative for this – rustproofing guns. Guns, or sprayers, call them whatever you like, these tools are what you need.

You can apply the protection even easier, faster and with more precision than with a spray can. Don’t believe me? Take a look at these models.

PMT Rustproofing Gun

If you ask me what is the best rustproofing gun available on the market, without any hesitations, I would recommend you this one.

PMT Rustproofing Gun review

The PMT Rustproofing Gun

It weighs just about 2 pounds and it is ideal for applying coating inside doors, beams and other metal surfaces. The pressure builds up inside the tank which helps you with the application as the spray tip will provide total coverage of the surface.

In case you were wondering what is the gun that body shops and car dealers use, you have found your answer. However, you will need to pay for the quality, and you can check the latest price of the PMT Rustproofing gun here on Amazon.


  • made of stainless steel
  • 1-liter capacity
  • 40-60 PSI working pressure

TCP Global Brand Pneumatic Air Undercoating Gun

But if you do not own a body shop, a gun that is not the best one will do the job for you. What rustproofing gun offers great value for the price?

TCP Global Brand Pneumatic Air Undercoating Gun analysis

The TCP Global Brand Pneumatic Air Undercoating Gun

Consider this one, a lightweight, handy and well-balanced tool designed for undercoatings and other purpose coatings. It is well-balanced and sturdy in construction, so you won’t need much effort to use it.

This rustproofing gun can spray very wide and the fluid can be adjusted just as you want. It can handle a wide range of water/oil based materials. Check the current price and customer reviews of the TCP Global Brand Pneumatic Air Undercoating Gun here on Amazon.


  • great for automotive coatings but other appliances as well
  • well-balanced, precise machine
  • sturdy in construction

Astro 4538 Economy Undercoat Gun

As the name speak for itself, you don’t need a loads of cash to buy a rustproofing gun. This may doesn’t have the best performances, but it is a quality gun that can satisfy your needs.

This rustproofing gun is small and very compact, and it weighs only 0.65 pounds. It can apply different undercoatings to vehicles in order to fight rust and stone chips.

It comes with two tubes with different length and it can be quickly assembled for faster cleaning. Check the latest price of the Asteo 4538 Economy Undercoat Gun here on Amazon.


  • ideal for rust and stone chips fighting
  • lightweight
  • easy to clean

When to do it?

The best time for rustproofing and undercoating is when you buy a new car. By new car, I refer to a vehicle that hasn’t been driven yet.

Many dealerships offer to do this for you, so maybe it is a good way to protect your car from the beginning.

The point here is that since the car is not driven, it is clean and you can apply the protection without cleaning it. However, as I said, you don’t need to pay loads of cash for it, so you can clean the car at your place and apply the protection.

But don’t apply the protection once, and then forget about it. You need to take care of your car regularly and look for any damage or rust areas on it.

The sooner you notice anything unusual, the better – as you will have more time to deal with it.

Types of rustproofing/undercoating

If you have done this in the past, you probably know that there are several types of protection. If not, now is the best time to learn something new.

Electronic method

It is a small device that stops the rust forming with a weak electric current.


Spraying a substance that acts as a barrier, which is personally, the best method of rust protection.

Oil spray – dripless

A substance similar to wax that is applied to the body, and when it hardens it offers maximum rust protection.

Oil spray – drip

Similar to previous, just the drip oil spray is continuing to drip when applied until they dry completely, which may take up to 2 days.


If you want to keep your car in a good shape, you need to take care of it regularly. Rust forming is one of the biggest issues you are about to face and you need to learn to deal with it.

Whether you need to prevent or clean the rust from your car, this article will guide you through that. With many products reviewed, I am sure you will find the best for you and solve this common problem.

What are your experiences with rust cleaning and prevention? How do you deal with the rust? Feel free to share your opinions in the comments section.

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