POR15 vs Zero Rust and Eastwood's Rust Encapsulator A couple years back I made some comments on various websites whereby I said that I could not see HOW a spray-can product (such as Zero Rust and Rust Encapsulator) could have the same properties - and therefore work/last the same - as would an epoxy-based product like POR15 (and now RustBullet), which are single-part epoxy products. Some time after making those comments, Zero Rust people and Eastwood sent me some of their product and asked me to try it, which I did. After several trials in my own restoration shop, I still felt the same way, but there were a few voices - some in the profession - still saying otherwise. It was then that I decided to do some actual "testing" of these products. While not a "scientific" test, it could well be called a "real world" or "as intended" trial. The products were used as recommended, the way an enthusiast would use them in their own shops or garages. In every instance, both Rust Encapsulator and Zero Rust were applied from the spray cans supplied, using 3-5 medium-wet coats. The POR15 was applied with a brush in a single, medium coat. Regardless of the number of coats or the perceived thickness of product application, all products were applied per their instructions, at temperatures near 60F/15C and as you would in practice, to both cover surface rust and to give the metal some protection from further rusting, as advertised by all 3 products. I have 3 experiences (or "tests" if you will) that I'd like to share: In the first instance, I applied Eastwood's Rust Encapsulator and POR15 to either end of a spare tailgate for my 1946 Mercury truck. This item had lived outside for a long time and had developed an even surface rust, making them the exact surfaces applicable for these products. Since the application of these products, this particular tailgate remained inside my shop, dry, at temperatures between 7C and 25C. In this trial then, the products were not subjected to harsh conditions (as per a subsequent, ongoing test) so we can see how they age on their own. After about 2 years, we can see that the Rust Encapsulator has become somewhat transparent, while the POR15 has remained solid and opaque (solid). Again, this part stayed inside my shop all this time, so I'm not sure why the Rust Encapsulator would have deteriorated on the panel, though I can make an educated guess: if you look closely, you can almost see the rust of the tailgate coming back through the Rust Encapsualtor coating in some spots, leading me to believe there is a lack of solids in the product. From that, one may infer that this product may not provide a long-lasting coating, nor long-term protection. 1946 Mercury Tailgate: On the left is the Rust Encapsulator, on the right the POR15. Below: If you look closely at the photo below, you'll see how the Rust Encapsulator has - for lack of a better term - worn out. You can almost see through it to the rusted surface in some spots. If exposed to the elements outside, I would guess the product would provide less than optimal protection. Below is the POR15 coated portion. It still looks solid and opaque. There doesn't appear to be a weakening or wearing of the product and rust-through is non-existent. Of course that being a fairly "easy" test - and certainly not the one everyone wants to see - I did a second test where the part (thsi time a Chevy tailgate) was left in the elements for an extended period of time: This time all three products (POR15, Rust Encapsulator and ZeroRust) where used on a Chevy tailgate that had been exposed to the elements long enough to produce a heavy coating of surface rust. After proper application of all 3 products, the tailgate has been left outside, throughout the seasons. This test was started about 6 months ago, so not yet ready to be reported on, but I'll do a full posting on the results in another 12-18 months, depending on how fast I see differences in the performance of the products. This third experience (below) speaks to the composition of these products, their robustness, as well as their ability to resist chemical degradation and protect what is under them: Most of us know that brake fluid is highly toxic to paint. In the photo below, the brake backing and tie rod on a 1956 Chevy Truck restoration were brush painted with POR15, but the wheel rim was sprayed with Zero Rust. After assembly and bleeding the brakes - and getting brake fluid all over both surfaces - we wiped it all down and noticed that some of the Zero Rust from the rim had been removed by the brake fluid, while the POR15 was still intact. Several days later, as we were checking over various systems, we noticed that the bleeder on this side was leaking, again allowing brake fluid to run over the wheel and the along the tie rod. So now both surfaces where in prolonged (several days) contact with brake fluid before being noticed and wiped down and still the POR15 remained intact. Below: Up close, one could see the POR15 was completely intact and would likely never be impacted by brake fluid. It doesn't take a rocket scientist (lucky for me!) to know that products in a spray can just cannot dry to the same hardness as would an epoxy (single or dual component). If they could, they would harden and ruin the spray tips on spray cans so that upon second use, they would not spray again. For anyone that has ever used POR15 (which cures in the presence of atmospheric moisture) you know just how hard it dries. It actually WELDS the lid to the can and it dries to a hard shell, regardless of how thickly or thin it is applied. On a suitably prepared surface (key point - read directions carefully), I've found that POR15 bonds like nothing else you'll ever try. Disclaimer: I do not work for any of the companies that make or distribute any of these rust products. After posting several threads about my use of POR15, the manufacturers/distributors of Zero Rust and Eastwood's Rust Encapsulator sent me more product to use and try. POR15 has never offered me anything. While I know that these products have their fans, I have as yet not seen an instance where POR15 has been outperformed by them in my experience. The POR15 I applied to the undersides of the 1956 Chevrolet truck is still performing well and looking great 3 years later. The truck won 1st Place at the huge Draggins Car Show here in SK, I'm sure partly due to the great OEM "suede" look you get by just brushing POR15 on surfaces.