This the best product for anyone trying to keep old cars from getting rustier. I've been fighting rust since the 70s when all there was was Naval Jelly. This stuff smells like Naval Jelly but works much better. Other products cover up the rust with pigments, this does not. It leaves the original look and goes on clear right over any color you are working with. A year or two later you can re-visit your work and touch it up by just spraying where the rust is orange again. The product turns rust black so you can really keep and eye on the rust without altering the original paint color or patina. It's better than the waxy oily products out there for rust because it's not a greasy slimy mess under your car. This stuff is a life saver for me, short of doing a frame off restoration it's my #1 weapon to combat rust here in New England.
My only issue is that stores only carry 1-2 cans at a time or they don't order it at all. CatQuest (in Colorado) informed me that Rust-Fix is not available anymore and has been replaced by Rust-Barrier. I hope that's not true. In response I bought a 6 pack on Amazon for my CO vehicle. Please keep making this product. Advertising is non-existent for Rust-Fix and I'm sure if people tried it for the purposes it was designed for they'd buy it up like semi-gloss black paint. It's not going to turn a rusty pile of junk back to showroom but it WILL keep lightly rusted original paint cars looking good and most importantly not getting any worse without altering the original factory finish. Of course I'm talking about the underbody where 99% of rust lives, but I've used it on exterior body panels as well. It's just great stuff and I can't say enough good things about it. I've heard people online say this and that like they expected a result like you get from a full frame off restoration. No, that's not going to happen but if you don't want to sand, sandblast, prime, paint, etc. then Rust-Fix is the answer. I like the fact that you can see if the rust is coming back because it's clear and doesn't hide or cover up the rust. It just converts it to a black material and encapsulates it.