POR-15 Rust Preventative Coating…

Written by on March 14, 2018 in Product Reviews with 0 Comments

…Because RUST never sleeps!

Neil Young is a master of the obvious, making us wonder if he ever used POR-15. The sad reality of rust is especially true for those of us who live in the Northeast, also referred to by vehicle owners as the Salt Belt.

rust preventionIn the winter, our roads are heavily salted to melt snow and ice. This goes on for months, exposing the undercarriage and chassis of our vehicles to the fastest rust formation imaginable.

Those of us with work trucks and recreational sport utes are especially sensitive to this issue. It is common for 10-15 year old vehicles to be in perfect shape body-wise, but a mess of corrosion underneath.

For many years, we have tried to slow rust down on our rigs, with only short lived success. Recently we brought a new (to us) product into the shop. A pricy new product.

So pricy, in fact, that our local Bond Auto Parts dealers don’t even keep it on the shelf. The guy at the counter told me that its so much more expensive than other products, that they often don’t bother to put it on display.

THAT is the kind of product we are looking for! Those of us who are painters know about the shellac based primer product commonly known as BIN. We were looking for a BIN for rust.

Upon researching and purchasing POR-15 locally, we were concerned about user friendliness of the product. Most of the online reviews by users were either raving success stories or frustrated complaints about how difficult POR-15 is to use.

Many complaints seemed related to management of the can, not surprisingly. Those of us who paint have a good understanding of how to keep a clean rim on the can and how to manage product on a brush…and even choosing the right brush comes into play here.

POR-15Some users couldn’t get the lid back off when it had been resealed after use…a sign of a gunked rim. Sure, the product will lock the lid right in place if there is excess wet product in the rim.

But with a clean, dry circumference upon closure, this is not an issue. Our cans opened and closed fine, and we didn’t have to drill holes in the cans to get product out, as some users reported.

We’d also read that the product was messy to work with and dried too fast. Our experience was in a controlled environment, in our shop. Certainly, POR-15 would be more challenging to use in an outdoor application…it doesn’t take much sun and wind to make any product more difficult to apply.

And it is always important to remember that surface temps play a huge part. With any product, there is more drag and quicker tack times when the surface is excessively warm.

All that said, here is how it went for us.

Applying POR-15 to a truck frame with surface rust is a bit of work. Especially without having the truck up on a lift. We did it old school: ramps, chocks, a really good 6 caster creeper and LED lights under the rig. Keep in mind, that this puts the user on his or her back, applying product essentially overhead, and with the brush (full of product) upside down. Not for the feint of heart, especially with this product. Safety First!

Applying POR-15

Our 2002 truck has spent its whole life in the northeast. Surface rust was present, but the frame was solid. Just due for a protective update. We chose the semi gloss black POR flavor, and went into the project with the full intent of topcoating, likely with Waxoyl.

POR-15 is counterintuitive because you don’t have to do much prep before using it. There are few products that you would feel confident applying directly to rust. All you have to do is scrape off loose, flaking rust. We used simple 1.5 and 2″ putty knives and a Festool Rotex sander where needed. POR-15 is an aromatic polyurethane base with polymeric isocyanate derivatives.

The term “aromatic” does not mean that it smells good (it kind of doesn’t). Aromatic is a product type, often discussed in comparison to aliphatics. Without geeking out on tech, the fundamental difference for our purposes is that aromatic poly is not as uv resistant as aliphatic. That is fine. The manufacturer clearly states this, and the product is intended to be topcoated.


I mentioned BIN earlier. The viscosity of POR-15 is similar to BIN…very thin, almost water like in consistency. We purchased in pint quantities, because of the reviews we’d read about can management issues. Many of the reviews correctly noted that the product goes a long ways. This is absolutely true. The manufacturer claims 96 sf coverage from a quart, and 384 sf per gallon. We are inclined to agree with these ratings, as we completed our entire truck frame and other undercarriage components using just 2 pints.

We used cheap throwaway china bristle brushes. Literally, some of the cheapest you can get, because there is really no cleaning a brush after use with a product like this. So, if you take on a POR project, stock up on chip brushes. We used 1.5 and 2″ brushes.

rust prevention

Road salt washes right off the semi-gloss. We will be topcoating soon.

The biggest challenge in use (in our application) was that the brush is constantly being pointed up to the frame (bristles up, handle down) which can quickly lead to product running down off the bristles, onto the handle and onto your hands.

The best way to manage this is to load the brush with small amounts of product. It takes time, but the cleanliness gain is worth it.

With rubber gloves on, things can get slimy and messy pretty quick. Especially when you are constantly repositioning your light for visibility under a vehicle.

So, go slow and keep it clean. This way, the majority of product ends up where you want it.


The true measure of adhesion for any paint product is how hard it is to get off your skin after use. Trust us on this one…you don’t want to get this product on your skin – at all. I did, and I can assure you that nothing will remove it once it has dried. I even tried scotchbrite scrubbing with various hand cleaners. You will literally have to wait 2-3 weeks for your natural skin exfoliation to occur, for the layer holding the product to go away. That’s a good sign for the product, and serious matter of awareness for the user.

POR-15Further, you DO NOT want to get this product in your eyes. Which is hard, when working under a vehicle and applying above yourself. A small drop in your eye will really, really sting. I quickly switched from typical clear glasses to full on sealed goggles. This also keeps rust flecks from landing in your eyes.

These are issues that slow down production, and are just not good for us. Wear rubber gloves, eye protection cover all of your skin. Many products recommend this practice, but with POR-15 it is absolutely important to use smart safety habits.

That said, when dry (within about 2 hours in our shop climate), the surface formed by POR-15 is rock hard. It reminds me of the hardness of the epoxy coatings we use on concrete garage floors. I tried to chip it off with a hammer and chisel, and it was near impossible to break the coating. The chisel was more likely to slide than penetrate. That’s what we want on a truck chassis, which is constantly getting pelted with stones and road debris.

How Pricy?

You can expect to pay in the neighborhood of $30 for a pint, $50 for a quart, and up to $160/gal. As above, we did our entire frame project with just 2 pints. I can’t imagine a scenario (at this point) where I’d need to purchase more than a quart container. Ultimately, I’d rather pay more for a product that will perform, so I only have to do the work once.

We’ve tried them all kinds of products over the years that claimed to control rust. Everything from Rustoleum to Extend. POR-15 is head and shoulders above the typical lines, and an especially remarkable performer for a single component product (no 2 part mixing required).

We haven’t topcoated the undercarriage yet, stay tuned for that, as the truck is undergoing a bit of a restoration currently. We will keep our readers updated on how the POR-15 base coat holds up on the chassis over the next season or two.

Learn more about this product at POR15.com.

Share your own experiences and ask questions below. We enjoy hearing from our readers.

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