The 10 Best Car Undercoating Paints to Buy 2021

The Ultimate Guide to Car Undercoating Paints

Undercoating your car is a complex job to undertake. You have to consider a lot of factors in order to protect your vehicle in the most efficient way possible. This section of our guide will provide an exhaustive source of all the important information you need to use and apply undercoating paints.

What Are Undercoating Paints?

Undercoating paints provide the most vulnerable part of your vehicle an added layer of protection against harmful elements that you may encounter every day, such as rocks, debris, salt, water, and other minerals that could negatively affect your car.

This kind of paint is typically applied to the car’s exterior, especially the undercarriage. It can also be applied to floorboards, suspension parts, frame, gas tank, pans, and wheel wells of your vehicle. If you’re buying a second-hand vehicle, you should always apply undercoating paint to prevent additional damage to its already fragile underbelly.

How Long Do Car Undercoating Paints Last?

How long your undercoating lasts depends on many factors, like what type of undercoating you used, how well you applied it, how you use your car, and even where you live. Generally, though, car undercoating lasts at least a full year.

If you often use your car on rough terrain or if you live near the ocean, where the chance of rust, corrosion, and chemical damage is greater, there’s a good chance you’ll have to apply undercoating at least once every six months.

Different Types of Undercoating Paints

There are several types of undercoating available in the market, such as water, petroleum, rubber, asphalt, and polyurethane-based paints. Each type has its own strengths and weaknesses that you should consider before picking out which paint is best for you.

Here’s an explanation of each one in a nutshell.

Water-Based

Water-based undercoating paints are the most commonly used paints for DIY undercoating projects. Like other water-based products, they have a thin consistency and dry faster than other types of undercoating paint. They’re also generally sold in aerosol cans for easy application.

The biggest disadvantage of water-based paints is that they wear out faster than other types. This means you’ll need to redo the coating more often for maximum protection, which could be a problem for those who don’t like high-maintenance vehicles.

Wax or Paraffin-Based

Wax or paraffin-based undercoating paints are some of the cheapest options around. They never actually harden and instead seep into the nooks and crannies of your vehicle to protect it from most elements. They are also stronger than water-based paints and can withstand more abuse and exposure.

This type of paint can be either painted on or sprayed, making application quick and easy. However, they still wear off pretty fast, which means you still need to redo the coating at least once a year.

Oil or Petroleum-Based​​​​​

Petroleum-based undercoating is a step above both water and paraffin-based options, as it offers much wider and stronger protection. It can repel road salts, oils, and debris much better than most other types of undercoating paints. Also, petroleum-based compounds are known to be effective at preventing corrosion in vehicles.

However, they’re harder to find in the market, and some petroleum-based undercoating like the Fluid Film Rust & Corrosion Protection never really dries fully – something not everyone likes.

Rubberized

Rubberized formulas are the second-strongest undercoats available on the market. This type of substance is designed specifically for rugged terrains and can withstand stronger exposure and abuse than any other formulas mentioned. They also offer additional features like sound deadening and resistance to dents.

These formulas are very easy to apply and can be painted on or applied as an aerosol spray. They can even be painted over in case you make a mistake and can be removed easily with any undercoating paint remover.

Polyurethane

Polyurethane is one of the most expensive undercoating options out there. It is self-sealing, which means it will seep into the smallest corners and cracks, sealing the surface where it’s applied and pushing out all the salt, sand, dirt, and moisture in the process. Due to this, it’s a great option if you want complete protection for not only your car’s underbelly but also its exterior in general.

This type of undercoating can be purchased in pails or canisters for coating guns. Keep in mind that you have to spend extra time prepping your car’s surface before you apply polyurethane. This includes doing tasks such as degreasing, sanding, and applying an etching primer to metal parts.

Asphalt-Based

Asphalt-based undercoating is designed for military all-terrain vehicles that often see rugged use. It contains some rubber material in it that can help in sound deadening as well.

Compared to other types of undercoating, asphalt-based undercoating is the strongest and the most long-lasting. It does have three downsides worth considering, however. First of all, it’s the most expensive undercoating option in the market right now. It’s also not paintable, which means it can only be used for your car’s underbelly. Lastly, asphalt-based undercoating takes the longest time to fully cure.

Benefits of Undercoating

Not everyone takes the time and effort to undercoat their car. Not that it’s a surprise, considering how many people see undercoating as an expensive waste of time. However, the benefits that come with undercoating can’t be denied.

Here are some of the most significant benefits of undercoating your car.

Provides Additional Protection

Daily wear and tear, when left unattended, can eventually result in irreparable damage to your car. Every time you take out your car for a spin, it accumulates dust, grime, and salt. It also gets exposed to moisture, chemicals, and oxidation. This can lead to rust and mold, two of your car’s biggest enemies.

A good undercoating can prevent all that from happening. It can even protect your car from physical damages like chinks, dents, or scratches. And since all the important parts are covered and water-proofed by the coat, undercarriage cleaning becomes much easier and less risky.

Saves You Money in the Long Run

Anyone who has ever owned a car before will know that repairs are expensive – sometimes, unbelievably so. For instance, it’s not unusual to see repairs for structural damage amount to more than the value of your car.

Remember, the undercarriage is the part that is always exposed to rough terrains, harmful chemicals, and other debris present in the road and the environment. By providing a solid layer of protection to a vulnerable part of your vehicle, undercoating can save you money in the long run. You wouldn’t have to spend so much on repairs if there’s nothing to repair in the first place, right?

May Help Offset Insurance Costs

Insurance providers base their quote on how high-risk your car is. For example, second-hand cars cost a lot of money to insure because they’re more likely to need repairs. Reducing your risks by providing your vehicle more protection may qualify as a discount towards your premiums, especially in states that see high cases of corrosion in vehicles.

Makes Your Vehicle Run Quieter

Undercoating typically contains rubber, allowing the formula to seal the entire underbelly of your car completely. The rubber layer not only protects the surface of your undercarriage from damage but absorbs road noise, as well. The added noise suppression in your vehicle’s interior results in a quieter vehicle and a significantly better driving experience.

Undercoating vs. Rust Proofing

Although people often use the two terms interchangeably, rust proofing and undercoating are technically not the same.

Rust proofing usually refers to applying rust inhabitant on specific spots where rust will most likely form on your vehicle’s body. It usually involves using a thin substance to coat your car and prevent it from developing rust over time.

On the other hand, undercoating is applying a thick, durable, and protective layer of material to the underbelly of your vehicle. It’s meant to cover the floorboard, frame, and the wheel wells – places that are very susceptible to physical and chemical damage in the long run.

Pros and Cons of Undercoating

When you apply undercoating, you’re providing protection to your car’s underbelly against all kinds of damages, rather than just rust. In addition to that, undercoating can also reduce the noise that your car generates on the road, something that plain rust proofing can’t do.

However, undercoating is merely a preventative measure, which means it’s more advisable for newer cars. If your undercarriage has already begun to rust, you’ll have to completely remove all the rust first before you can apply undercoating. Depending on the condition of your vehicle, this can be extremely expensive.

Pros and Cons of Rust Proofing

Rust proofing is meant to lengthen your car’s lifespan as well, and for a typically cheaper price than undercoating. Unlike undercoating, you can still apply rust proofing to areas that have already begun to rust. Rusting is a chemical process, and like all chemical processes, it can always be delayed or stopped – if caught early.

However, rust proofing is becoming less and less popular with the arrival of newer, more rust-resistant materials that cars are made of. Galvanized steel, for example, greatly increases the resistance of car surfaces to rust, making rust proofing a costly redundancy. On the contrary, this doesn’t apply to undercoating, as undercoating protects your car from more than just rust.

Rust Proofing or Undercoating?

If you’re on a tight budget and can only choose one of the two, you should look first at the specific problem you want to solve.

For example, if owning a vehicle for you is all about keeping the exterior spotless and looking good, rust proofing is enough. However, if you’re more concerned about how your car will hold up over ten or so years, then undercoating is a better option.

However, if you have the means to avail both for your car, you don’t have to choose at all. Rust proofing and undercoating are not mutually exclusive – in fact, they complement each other pretty well. Getting both can give your beloved ride the best protection it needs and deserves.

Methods for Applying Undercoating Paints

Different types of undercoating may need different methods of application. Here’s a quick explanation about the two main methods used to apply car undercoating paints.

Brush or Roll

One way to apply undercoating paints is by using a paintbrush or a roller brush. Water-based, wax-based, paraffin-based, and rubberized undercoating typically use this method. It’s very straightforward even for beginners because you can easily control the brush, which means you can paint more than just your car’s undercarriage. The only downside is that it can take up a lot of your time.

Spray

This is the most widely practiced method for applying undercoating to vehicles. Spraying makes sure that the material will adhere properly to your vehicle’s underside to protect it from the elements. However, it can be quite difficult to get an even spread. It’s best to use this method on a new car the day you bring it home.

How To Apply Undercoating Paint

Undercoating your vehicle, although simple in theory, can be an arduous task. To help you out, here’s a step-by-step guide to applying undercoating paint to your car.

Materials

• Scraper
• Degreaser
• Disc grinder and grinding pads
• Sandpaper
• Dry rag
• Primer
• Undercoating
• Workshop safety goggles
• Protective gloves

Steps

1. Thoroughly clean your vehicle’s undercarriage with a good degreaser. Make sure that no part is left uncleaned.
2. If there’s any rust present, grind it down with a disc grinder.
3. Sand down any rust that remains. There should be no rust present before you begin undercoating.
4. Once that’s done, it’s time to prime the clean undercarriage. If you’re using polyurethane undercoating, etching primer is needed for bare metal parts. Allow the primer to dry completely before proceeding.
5. Liberally apply undercoating to the undercarriage of your vehicle. Cover all of the exposed parts such as the wheel wells, the frame, the floorboards. Let this first coat dry for at least an hour.
6. Once the first coat has dried, apply your second coating of undercoat.
7. Let the undercoating dry for 24 hours at a minimum before you use your vehicle.

If you want to remove undercoating from your car, apply the appropriate paint remover product for the type of undercoat you want to remove. This includes solvents, aircraft strippers, or paint strippers. You can also use a heat gun to soften the undercoating first.

Once the undercoating has already softened, use a scraper to scrape off the undercoating paint, taking care not to damage your vehicle.

What’s the Best Method for Cleaning My Undercarriage?

The best method is to get a professional car wash service to clean your vehicle’s undercarriage thoroughly. However, if you prefer–or don’t mind–doing it yourself, power washers are the best way to get all the dirt and grime off your car. If you don’t have a power washer, a regular garden hose is the next best option.

That said, keep in mind that you’ll have to check more thoroughly if you’re using a garden hose since the pressure may not be strong enough to remove dirt that has already hardened over time.

Also, both power washers and garden hoses aren’t the be all and end all of the undercarriage cleaning. You still have to apply a degreaser and then grind down any instances of rust before applying the undercoat.

Should I Remove My Wheels When Applying Undercoating?

Yes, you should. It may seem like a chore, but you should always remove the wheels of your car before you apply undercoating, especially when using spraying methods. Undercoating is a substance that hardens over time, so if you get it on your wheels, it will form a lump that may throw off your vehicle’s balance while driving.

Once again, always remove all removable parts of your car before undercoating to ensure that the whole process goes smoothly. It’s better to be safe than sorry, after all.

Tips For Undercoating Your Car

Here are some additional tips that you should keep in mind before you undercoat your car.

• Never apply undercoating to a dirty undercarriage. Once your car has been undercoated, you won’t be able to clean the surface underneath it anymore. Any dirt, mildew, or rust trapped there will slowly corrode your car’s undercarriage.
• It can be a real pain to clean the mud, dirt, and dust from the underside of your car. To easily rid the undercarriage of road gunk, use a pressurized washer. Once it dries, you can proceed to grinding and sanding down rust, if any. You can also use a rust remover to make sure that no rust remains.
• Most undercoating products will never stick to greased surfaces, no matter how long you dry it out. Always use a degreaser to completely remove grease from your car’s surface.
• If you’re using an aerosol spray, do a trial spray first to see the can’s fan pattern. Spray up and down if the paint comes out in a narrow stream, but if it comes out tall and fan-like, spray side to side.
• Always use safety goggles and a sturdy mask when undercoating. During the process, you’re going to be exposed to a lot of harsh chemical fumes, so it’s best to protect yourself.

Final Words

This list showed you the best undercoating paints that you can get on the market right now. All of them are great options–some more suitable for your situation than others.

Regardless of what you pick though, undercoating is a great way to protect your car from daily wear and tear, prevent rust and corrosion, and prolong its lifespan. Not only does it save you money in the long run, but it also saves your car from otherwise preventable damages.