LAST UPDATED: May 29, 2021

Best Rust Prevention Spray for Cars: Rustproof Both Old and New Cars

Best Choice VHT Rust Converter VHT Rust Converter
Best Price Evapo-Rust Rust-Block.jpeg Evapo-Rust Rust-Block
Premium Pick Rust Bullet Metal Jacket.jpeg Rust Bullet Metal Jacket

By:  Norah Tarichia

It’s usually during spring or summer when rust appears on your vehicle—that’s when the moisture and road salt that accumulated during winter starts to act on the metal. As the temperature rises and the metal expands, rust gets a bigger surface to act on and even spreads to other areas. A few decades ago, this would mean that your vehicle’s bodywork and even the internal components are on their last leg but currently, rustproofing products have reshaped the auto industry. Vehicles can now last as long as they should, thanks to undercoats, waxes, and even rust prevention sprays. 

Not only are rust prevention sprays easier to use, but they can better penetrate every nook and cranny of your car, so it gets the best protection. We will guide you through the selection process so you can find the best rust prevention spray that will help maintain your car’s structural integrity.

The Best Rust Prevention Spray for Cars

VHT’s rust remover for cars is a powerhouse when it comes to fixing rust problems. When sprayed directly onto metal, rusted areas are destroyed on contact, leaving behind an even black coating that also acts to prevent more rust from forming in the future. The formula can be safely applied not only to metal but also to body filler and fiberglass, making it one of the most diverse options on the market. Many people have used this product to salvage metal that would otherwise have gone to the scrap heap, making it a great option for thrifty hobbyists. You can paint over the tough film that the product forms following 24 hours of drying time, so you don’t need to sacrifice the appearance of your equipment to get the most out of this product.

While it may be a decent product even for high-heat applications the 24-hour drying time is a bit long in comparison to other solutions. This means that you may even have to wait longer when removing heavy rust.

Key Features
  • Rust converter and stopper
  • Dries in 24 hours
  • Sprays on clear then turns black
Specification
  • Brand VHT
  • Model SP229
  • Weight 14.2 oz
PROS

Suitable for use on metal, body filler, and fiberglass

Converts rust into a black, rustproof protective coating

New protective coating can be easily painted over

Safe for non-metal surfaces

CONS

Takes long to dry

Nozzle tends to clog

Ideal for vehicles that will be sitting idle in humid conditions for a long period, Evapo-Rust Rust-Block forms an effective seal against rust. It’s a water-based rust inhibitor that’s eco-friendly and non-toxic so you can apply it even without wearing gloves. Once sprayed on, the product dries within minutes and leaves a thin, transparent protective film that can resist rust for up to a year if your vehicle is stored indoors. When it’s time to reapply a fresh coat, you don’t need a chemical cleaner or rust solvent to remove the film. A simple warm water rinse will do. The product is safe for all auto parts, garden equipment, farm tools, and hardware.

However, you should note that it’s not designed to be painted over. You need to remove the coating, and only then can you coat the surface with oil, paint, or a primer.

Key Features
  • Water-based formula
  • Leaves a thin transparent protective film
  • Non-flammable
  • Biodegradable
Specification
  • Brand Evapo-Rust
  • Model RB015
  • Weight 16 oz
PROS

Fast-drying

Offers long-lasting protection

Safe on skin

Can be easily removed with warm water

CONS

Not designed to be painted over

Not resistant to the elements

Not ideal for frequently used or offroading vehicles

If salt spray, chemical fumes, high humidity, and other corrosion-inducing factors are having your vehicle looking old and unsightly, then the Rust Bullet Metal Jacket may be the solution you need to keep rust at bay. It’s a military-grade, non-chlorinated, rust and corrosion prevention formula that can be used on all types of metal. It leaves a non-greasy and amber-colored protective film so you can easily identify the treated areas. The protective film is also flexible and resists cracking, peeling, or flaking within a temperature range of -40 to 125 degrees Fahrenheit. Therefore, it’s reliable even in freezing temperatures. The film can be removed with the Rust-Bullet solvent.

However, it’s not designed to destroy rust so you shouldn’t apply it over an already rusty surface. It’s also on the expensive side.

Key Features
  • Military-grade rust prevention
  • -40 to 125 degrees Fahrenheit working temperature
  • Non-greasy and dirt resistant
Specification
  • Brand Rust Bullet
  • Model 00856084000395
  • Weight 13 oz
PROS

Offers cold weather protection

Protects against salt spray

Leaves a flexible and durable film

Safe on other non-metal parts

CONS

Doesn’t destroy rust

Somewhat expensive

Boeshield’s anti-corrosion spray was developed by the Boeing Company to lubricate and protect aircraft components. It combines anti-corrosion technology with waterproofing and lubrication. Boeshield’s T-9 solution loosens rusted and corroded parts while displacing dirt and old lubricants and works its way into moving parts for better lubrication. It dries to a thin, waxy layer that clings to the metal and protects it for months. Boeshield’s T-9 formula is safe to use on any metal surface, as well as paints, plastics, and vinyl. This makes it diverse enough for use with everything from bicycles to cars, to tools. It’s also a cost-effective way to give your car the protection it needs.

The main complaint we noted from most users is that the product tends to clog up the nozzle. Therefore, you have to constantly wipe the tip. It’s also a bit pricey.

Key Features
  • Rust protection and lubrication
  • Dries to a thin, waxy layer
  • Suitable for use on exposed metal, painted metal, plastics, and vinyl
Specification
  • Brand Boeshield
  • Model 122182
  • Weight 15.8 oz
PROS

Provides rust protection, lubrication, and waterproofing

Loosens existing rust

Displaces dirt and existing lubricant

Can last for months

CONS

Tends to clog the nozzle

Somewhat pricey

Quickly convert rust into a paintable surface with the Rust-Oleum Rust Reformer Spray. The solution contains synthetic polymer epoxy that chemically bonds with rust and converts it into a black, non-rusting, paintable surface that resists future rust. The spray nozzle features any-angle spray technology with a comfort tip so you can spray in any direction, even upside down. It takes about 20 to 40 minutes to dry depending on the quantity you used. For best results wait for at least 24 hours before applying a topcoat. You can use this rust reformer on engine blocks, axles, exhaust manifolds, and other rusted metal surfaces, even ones with lacquer or oil-based industrial paints.

While it may convert rust into a paintable surface, you still need to remove excess rust with a sandpaper or wire brush before painting the area so you can get a smooth finish.

Key Features
  • Water-soluble and odorless
  • Any-angle spray technology
  • 200 degrees heat rating
Specification
  • Brand Rust-Oleum
  • Model 248658
  • Weight 12 oz
PROS

Compatible with automotive paints

Converts rust into a paintable surface

Prevents future rust

Quick-drying formula

CONS

May take longer to reform heavy rust buildup

Excess rust needs to be removed with a sandpaper

If you are looking to restore the look of your antique car, then the Rust Kutter Professional Rust Repair can help restore your vehicle to its original glory. The solution works to destroy rust by converting it into phosphate. It then bonds with the metal to prime the surface, and keeps moisture and oxygen out so rust or corrosion doesn’t attack the metal. The solution is non-viscous so it spreads easily and a few spritzes can cover a large area. Besides your car, you can use it to treat or stop rust on other areas, including trucks, farm equipment, garden tools, door hinges, and more.

However, you should take caution when using this product by wearing gloves; it can irritate the skin. It also has a strong odor so consider wearing a respirator and working in a ventilated area.

Key Features
  • Converts rust into a phosphate
  • Metal primer
  • Multi-purpose
Specification
  • Brand Rust Kutter
  • Model 08088
  • Weight 32 oz
PROS

Removes heavy rust

Treats the surface to prevent rust

Safe for cars and a variety of outdoor equipment

Spreads easily and covers a wide area

CONS

May irritate your skin

Has a strong odor

Before your car gets a rust problem, consider treating it with the Krylon Fusion All-In-One Paint Primer to protect against rust. The solution creates a strong bond with bare metal to keep out moisture and oxygen. After about two hours, it dries into a glossy, spring-grass-colored finish that can be used as a primer if you intend to apply a top coat of a similar color. You’d have to wait for at least 24 hours before you can recoat it. A single, 12-ounce bottle covers up to 25 square feet, and the any-angle spray nozzle makes it easy to spray the product even if you hold the spray can upside down. For best results, it should be applied on a surface with a temperature range of about 55 to 75 degrees Fahrenheit.

Just be warned that the color may be a bit off, so there’s no guarantee that the color on the spray will be an exact match to the sprayed-on solution.

Key Features
  • Rust preventive primer
  • Any-angle spray technology
  • 55 to 75 degrees Fahrenheit application temperature
Specification
  • Brand Krylon
  • Model K02724007
  • Weight 12 oz
PROS

Maximum adhesion for durability

Can be used on any surface

Provides a colorful and glossy finish

Can be painted over

CONS

Color may be a bit off

May have bubble pockets if you do multiple coats

3M is known for its high-quality automotive products, and this rust undercoating spray is no exception. Available in both rubberized and non-rubberized options, the unique, asphalt-based formula dries to a black protective coating that effectively protects against corrosion. The no-run solution makes it easy to apply, whether you’re protecting a car, truck, or recreational vehicle. The coating is also easy to apply due to its built-in aerosol dispenser. Another great feature of this spray is that, when you apply it correctly, the layer of rust protection also acts to absorb and deaden road noise.

You should note that this is only a preventive formula and shouldn’t be applied to an already rusty area. It will trap moisture and oxygen underneath it, and most likely cause deeper damage to the affected area. Use it only on clean metal.

Key Features
  • Professional-standard undercoating
  • Asphalt-based formula
Specification
  • Brand 3M
  • Model 03584
  • Weight 16 oz
PROS

Protects against corrosion and abrasion

Perfect for undercarriages, wheel wells, floor pans, and more

Helps to deaden road noise

CONS

Doesn’t destroy rust

Has an unpleasant smell

When CRC says “heavy-duty,” it means it. This corrosion inhibitor provides a tough but flexible coating that’s suitable for a huge range of metal components. The spray is easy to apply, and its carefully blended formula is designed to creep into every nook and cranny before firming up to provide a durable layer of protection. Suitable for marine use as well as automotive applications, CRC’s rust-proofing solution will hold its own even in wet, salty conditions. CRC recommends using its product on everything from electrical connections to engine components and trailers. Users report that this spray provides a thinner, more even coating than many of its competitors.

Unfortunately, the design of the nozzle may make it a bit challenging to deliver the solution in tight spaces. Also, if your vehicle has brightly colored paintwork, reconsider using this product since it may leave behind a yellow residue.

Key Features
  • Corrosion inhibitor
  • For automotive and marine applications
Specification
  • Brand CRC
  • Model 06026
  • Weight 1.44 oz
PROS

Heavy-duty rust proofing holds up even in marine conditions

Provides a tough but flexible coating on any exposed metal

Offers a more even coating than many options on the market

Long-lasting effects

CONS

Can be challenging to direct the nozzle in tight spaces

May leave behind a yellow residue

When your car is completely covered in heavy rust and ordinary rust removers just don’t cut it, you can try using the STP Pro-Series 3-in-1 Anti-Rust Protection. It’s a three-in-one formula that’s designed to penetrate rust to destroy it. It then displaces moisture to create a protective barrier against rust and corrosion. Lastly, it lubricates the surface. The spray comes with a permanent straw that can provide either a wide spray or a precise stream. It can even be used upside down. Since it’s a versatile product, it can also be used to keep metal from overheating when used as cutting oil.

Unfortunately, it’s only available in a small 11-ounce container so you may need more than one spray can if you intend to cover your entire car.

Key Features
  • Three-in-one formula
  • Penetrates and lubricates metal
  • Ideal for home and auto use
Specification
  • Brand STP
  • Model 18274
  • Weight 11 oz
PROS

Fights rust and corrosion

Can provide a wide spray or precise stream

Lubricates moving parts

Can be sprayed upside down

CONS

Small quantity

Slight learning curve to using the straw

Best Rust Prevention Spray Buying Guide

That concludes our rundown of the best rust prevention solutions on the market. There are plenty of options to choose from, and despite being rust prevention formulas, each carries its benefit for your application. So how do you determine which one goes on your car? It’s simple. You need to understand your vehicle’s needs and look for a product that meets those demands. For example, if you live in a humid area or near the coast, you need a formula that’s not only waterproof but resists damage from salt and corrosive minerals. Read on to find out more about rust prevention sprays so you can make an informed buying decision. 

Do You Need a Rust Prevention Spray for Your Car?

Rustproofing cars are one of the single best ways to keep vehicles in the best possible condition. Corroded components are more likely to fail over time, and could be costly and difficult to fix. Because of this, rust-proofing your car is a small investment that makes for huge benefits further down the road (pun not intended). 

Also, it doesn’t matter if your vehicle is new, used, or a classic car. You still need to rustproof your vehicle to make it safer, last longer, maintain its appearance, and make it more structurally sound. 

Below are just a few of the many benefits you can expect from using a rust-proofing treatment on your vehicle:

  • Ensuring a vehicle is adequately treated for rust increases its resale value
  • Repairing rust damage is a costly and time-consuming endeavor, which can be avoided by preventative rust-proofing
  • Over time, rusting compromises how well your car’s components perform – because of this, applying a rust prevention treatment improves its overall safety
  • Stopping rust before it starts is a simple way to significantly increase the lifespan of your car

Different Kinds of Rust Prevention Spray for Cars

rust prevention spray

Rust prevention sprays come in three forms: primers, removers, and inhibitors. All these types have different functions but can also be used together depending on your end goal. Let’s dive deeper into the types so you can learn how to differentiate them. 

Primers 

A primer spray ideally seals and bonds with the surface, and forms a rustproof foundation so a topcoat can be applied. Priming the surface helps to ensure maximum adhesion with the base and topcoat for a perfect paint job. It’s used on a new surface that’s free of rust and works best on even surfaces. It usually stays wetter for longer than other rust prevention formulas so the solution can penetrate deeper into the surface and offer long-lasting protection. 

The difference between a primer and an undercoat is that the latter is usually applied on a vehicle’s undercarriage or on a surface that has been painted before. Primers are typically used on new surfaces.  

Removers 

A rust remover or converter is usually applied on a rusty surface and the solution chemically combines with rust to convert it into a non-reactive, protective barrier. This helps to prevent rust from forming. Some rust removers can force rust to break away from the surface, and still leave a protective film that prevents further oxidation. Other options convert the rust into a paintable surface so you only need to sand away any excess product before applying a primer. 

If you have a classic or used vehicle, a rust remover spray with rust proofing capabilities is the best option to remove all traces of rust. It can be used on almost all types of material, including fiberglass, stainless steel, galvanized metal, and metal alloys. 

Inhibitors 

A rust inhibitor or rust stopper is a chemical solution that slows down or stops rust or corrosion when applied to the affected area. It also creates a protective barrier on the metal that keeps out oxygen and water. Most solutions also lubricate the surface. After treating the surface, you can use a rust remover so you can brush out heavy rust then you can add more of the product for further protection.

What to Consider When Buying a Rust Prevention Sprayrusty wheel

Below we work our way through some of the most important factors to bear in mind when choosing your rust prevention spray:

The Surface To Be Treated

When choosing a rust prevention treatment, one of the first things to check up on is what type of surface the product is suitable for use. Plenty of rust prevention and vehicle undercoating solutions are suitable for use on fiberglass and body filler as well as metals, but this is not always the case. Be sure to check the manufacturer’s advice before purchase.

Removal or Prevention

Another key factor that will influence your decision is whether you want to deal with existing rust, or simply prevent it from forming in the future. Solutions that remove rust as well as preventing its formation effectively allow you to paint over rust. Most of the solutions on this list perform both functions, but it’s always a good idea to double-check.

To Paint Or Not to Paint

If you are planning to treat a visible surface, make sure you choose a rust inhibitor that can also act as a primer, so you can easily paint over it. Bear in mind that products designed to convert existing rust tend to leave a dark brown or black surface behind, so you will probably need to apply at least two or three layers of paint to adequately cover it.

Application

If you dislike the idea of working your way over multiple uneven surfaces with a wire brush, you may wish to choose a rust inhibitor that can be applied via spraying. Most can be, but if you do not have your spraying equipment, it could be worth selecting a formula that comes in a spray can as standard paint over rust.

Related Posts: Best Car Paint, Spray Paint For Rims and Automotive Touch Up Paint

Best Rust Prevention Spray for Cars FAQs:

Q: What is a rust inhibitor?

A rust inhibitor is a formula designed to slow down the chemical process of oxidation which results in rust. They can work in a few different ways:

  • Providing a thin protective coating to keep iron away from the oxygen in the air
  • Absorbing oxygen that could otherwise react with the metal
  • Inhibiting the chemical process of either reduction or oxidation, both of which are necessary for the formation of rust

The solutions on this list work by the first method.

Q: How does corrosion take place?

When iron rusts, the process is a type of corrosion. Rust is the common name given to iron oxide, which forms gradually whenever iron or an iron-based alloy is exposed to oxygen for extended periods. This is because iron is a relatively reactive metal, which can form chemical bonds with many elements.

Q: What’s the difference between rustproofing and undercoating?

Rustproofing involves using a rust inhibitor to treat any area of the car where rust may form. Undercoating is the process of applying rust- and scratch-proof coating to the undercarriage of the vehicle so it can be more resistant to wear and tear. 

Q: Is it worth getting rust protection for a new car?

Yes, it is. Even new cars aren’t foolproof against rust, especially if they are frequently stored outdoors where they are exposed to the elements. Rust protection helps to keep your vehicle looking new for longer

Q: How often should I rustproof my car?

On average, you should rustproof your car at least once every two years. If you live in a humid environment, then you should rustproof your car every year. You can increase the frequency to every six months depending on how often your vehicle is exposed to rust-inducing conditions

Our Top Pick

The VHT Rust Converter stands at the top of our review because it’s an effective rust remover that removes rust on contact, and creates a black coating that protects against future rust and corrosion. It’s safe to use on almost any rusted part of your car, and you can sand it to get the finish you desire. 

Final Thoughts

While the VHT Rust Converter is a soli choice, especially if your car has pre-existing rust, you can also opt for the Evapo-Rust Rust-Block. It’s eco-friendly, reasonably priced and can offer up to a year of rust protection.