POR-15 vs. Rustoleum: Rustproofing Coating Comparison Guide

As winter draws near, most truck and SUV owners are looking for a way to protect the underside of their vehicles from the rust and damage that winter roads cause. There are dozens of rustproofing agents available, but it can be difficult to know which is the best.

Por 15 vs. Rustoleum

If you are deciding between POR-15 and Rustoleum, you have narrowed it down to two of the biggest brands of rustproof coating.

Here is a complete comparison of the two products to help you decide which will work best for you and your vehicle.

While Rustoleum has been around for longer, POR-15 offers a more comprehensive product for rust. However, both will get the job done, so it’s up to you to decide!

What Is POR-15?

POR-15 is a high-performance rust-prevention technology that has been around since 1978. Instead of a singular anti-rust spray, POR-15 has a several-step process meant to completely coat the underside of a car or truck and permanently prevent rust.

POR-15 offers an entire line of anti-rust products, from a single coat of rustproofing coating to an entire car detailing line. However, we will focus on the POR-15 anti-rust system. It’s a three-step system that includes a cleaner, a metal prep, and a rust-preventative coating.

What Is Rustoleum?

Rustoleum is another huge automotive brand dedicated to a full lineup of car supplies. Rustoleum has been in business for over 100 years and has been focused on making vehicles safer and more efficient. With a wide array of products, Rustoleum covers many automotive needs.

However, the anti-rust spray is one of the best-selling products in the Rustoleum lineup and the reason the company has its name. Rustoleum’s Rust Reformer spray is a simple, one-step spray that eliminates the need for sanding or anti-rust products.

POR-15 vs. Rustoleum Similarities

While the two companies provide different products, their anti-rust lines are similar. Before we dive into how Rustoleum and POR-15 differ, we’ll talk in-depth about what makes them both work similarly. Here are the four main similarities between the two products.

Anti-Rust Coating

POR-15 and Rustoleum both provide a safe, fully effective anti-rust coating. Whether painted or sprayed on, the anti-rust coating will prevent water from rusting out the underside of your car and protect the exposed metal.

No Need for Sanding

One of the biggest reasons to anti-rust coat your car is to prevent the need to sand down the metal until the rusty bits are gone. When rust starts to spread, many car owners will sand and repaint the entire underside of their car. With both POR-15 and Rustoleum, however, no sanding is necessary. You can simply paint them over the rust on your car.


Although POR-15 markets itself as a three-step system and Rustoleum is just a spray, both have the same basic principle. The actual anti-rusting material coats the bottom and sides of the metal and protects it from the formation of rust. Both are watertight and won’t allow water, salt, or other damaging products to hit the metal.


Once you’ve coated your rusty metal car with POR-15 or Rustoleum, you can safely put car paint over it. There’s no need to add another layer of primer or a different product. The rust preventatives are both paint-ready and act as a primer (both are black but come in different colors).

Por 15 vs. Rustoleum

Differences Between POR-15 and Rustoleum

While there are several similarities between these two products, it’s the differences that make them stand out. Both save your car from rust and primer it for a fresh coat of paint. Both products can come as paint or as a spray. However, here is what makes the products different from each other.

POR-15 vs. Rustoleum Features Comparison

Here is an overview of the main features of POR-15 and how they compare to Rustoleum:

  • POR-15 comes in a recommended three-step process, which includes cleaning (Rustoleum only has one step)
  • POR-15 is in paint form (Rustoleum is in a spray can)
  • POR-15 is a rubberized paint, while Rustoleum is oil-based
  • POR-15 requires a primer, while Rustoleum does not

Rubberized vs. Oil Based

Although both products are based on inorganic zinc to prevent rust, the oils that form the liquid in Rustoleum result in an oil-based paint cover. However, POR-15 ends up with a more rubberized seal. Both are equally effective in removing rust, but POR-15 is sturdier against rocks and scratches.

Primer and Paint

One of the biggest differences between the two products is the steps it takes to apply them. While Rustoleum has a simple one-step spray can, POR-15 requires a three-step process of cleaning, prepping, and painting the metal. Rustoleum recommends that you clean your car before painting it with the product, but it doesn’t require that you buy cleaning supplies.


Both of these products advertise permanent rust solutions. However, the durability of Rustoleum is a little better than POR-15. While POR-15 lasts well under heavy rains, snow, and gravel, it tends to fade and stretch in the sun. If exposed to heavy weather without a topcoat, POR-15 might not last longer than a few years.


However, POR-15 does outperform Rustoleum when it comes to strength. In power washer and gravel driving tests, a car coated in Rustoleum sustained more damage than one with POR-15. Of course, both should be covered with a topcoat to prevent sustained damage to the rust-prevention system or the metal underneath.


For some people, price is the deciding factor when it comes to car products. As of writing, a pint (16 fluid ounces) of glossy-black POR-15 costs $42.99 on the POR-15 website. However, a 10.25-ounce spray bottle of Rustoleum sells online for as low as $9. You will need more Rustoleum to thoroughly coat a vehicle, however.

POR-15 vs. Rustoleum Pros and Cons

Here is a quick comparison of the pros and cons of both products.

Ready for paintMore expensiveLess expensiveEasier to damage
Scratch-resistantSeveral step processOne-step processRequires more Rustoleum
PermanentDoesn’t hold up in the sunEasy-to-use spray canIsn’t a final coat
Seals rust inCan peel offPrimes and holds 

Which Is Better POR-15 or Rustoleum?

In the end, both POR-15 and Rustoleum are high-quality materials that come with a bit of a higher price tag. Where POR-15 does better against water and snow, Rustoleum holds up better against time and sun. Both have good reviews and will tend to peel after a few years.

When you are deciding which is better, it depends on where you live and what you are looking for. If you live in sunnier, drier areas, Rustoleum might be your top choice. However, if you are willing to spend a little more money for a product that takes some more time to apply, POR-15 won’t let you down.

Can You Paint Rustoleum Over POR-15?

Because Rustoleum is a spray and POR-15 is a primer and paint, it is possible to use both on your truck. They have the same base chemical to keep the rust away, but priming your truck with POR-15 and spraying Rustoleum over the top might be an excellent way to keep the rust off throughout the summer and winter months.

POR-15 and Rustoleum Alternatives

If you’ve read this comparison and want to find a different choice for your anti-rust needs, here are three of the best alternatives to POR-15 and Rustoleum.

PPG Industries Industrial Coatings

While it’s almost as large of a brand as Rustoleum, PPG Industries has managed to sell its products around the world and in several huge supply chains. PPG Industries is essentially a paint company, but they have a line of rustproof primer and paint that works to prevent rust and coat a vehicle.

FDC Ultra Rust Converter

Created especially for the undercarriage of cars, FDC Ultra Rust Converter converts rust into a coating and provides a primer at the same time. The rust won’t spread, and you won’t need to worry about reapplying it every season. You can just cover it in paint.

Fluid Film

If you live in especially wet or snowy climates, Fluid Film is a great choice. It was created for off-shore rigging and oil rigs and needed to be reapplied every year. However, no liquid or air will get between the Fluid Film and the car as long as it’s applied correctly.

Where To Buy POR-15

Whether you decide to buy POR-15 on its own or as part of a three-step rust prevention program, the first place to look is the POR-15 website. It is available on Amazon and at some Walmart stores but doesn’t feature in large retailers outside of auto mechanics.

Where To Buy Rustoleum

Rustoleum, on the other hand, is available at most large retailers, including AutoZone and Walmart. You can purchase it online from Amazon or the online section of these stores. Rustoleum has an online shop and offers a zip-code-based search site for stores near you that might have the product.

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Author: Dave Johnston

Dave Junior is a hands-on automotive technician with experience in performing service, diagnostics, and repairs on domestic and imported vehicles. He enjoys writing and sharing his knowledge far and wide.

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