Hey Scotty, I bought a 2011 Nissan Frontier 147K miles 4x4 and it lived most of its life in New Jersey. They have put salt on the roads, and most of the rust I see is superficial, though my control arm assembly is flaking and rusting. Is it a smart idea to use Rustoleum? It claims to convert rust to primer. I’ve already had the job done on my truck. The Frame though is solid as a rock, I’ve hammered it, and it is not flaking at all. So does Rustoleum actually stop the rust from spreading?
If the surface is properly prepared, and there is very light rust, the Rustoleum rust converter MAY work. My 1999 Ranger 4×4 has the torsion bar suspension in the front end, and the steel covers for the adjusters were covered with a fine layer of surface rust. A couple years ago I took a manual wire brush and got rid of all the dirt and loose rust, then sprayed the covers with the rust converter. The rust hasn't come back that I've seen.
Preparation is critical for this. Phosphoric acid is the key ingredient in the paint, it reacts with iron oxide to produce iron phosphate, which is hard and adheres to the steel, providing the original iron oxide is. I would not use it in areas where you can't easily get to. If the coating is compromised at all (dirt or loose rust under the paint) it will just cause more rust. I used the product on the outer faces of my frame rails where they are easy to get to, they haven't started rusting again, nor have the covers for the torsion bars.
Alright, I didn’t prepare it at all. What should I do? I just painted Rustoleum with my truck on a lift. Do I need to try to remove it? And clean all the rust off with a wire brush? Then use Rustoleum again? Or what do you recommend I do? Should I just wait till the Rustoleum wear off, and then do it?
I would redo what you can get to. If you have a grinder, use a wire brush attachment and take it down to bare steel, then prime and paint it with regular Rustoleum paint, not the rubberized undercoating stuff they make. Anything rubber will trap moisture and oxygen.
If you're able to clean the rust off then why use a rust "converter"? In other words, what rust is there to convert after cleaning? I'd like to get something that you just spray on that neutralizes/converts the rust. If there is such a thing.
Converters are meant for things with light rust (rust that looks like a powder coat, is very fine and tightly adhered to the underlying metal). Think of rust on your rotors overnight after it rained. If you put converter on steel with any degree of scale rust (rust that's flaky, looks like alligator skin) you will convert the surface of the rust, but it will not get down and seal to the base metal. There is moisture and air trapped beneath the scale, which will continue to corrode the steel and eventually cause the scale you neutralized to fall off, exposing the area again and repeating the process. If you want to use a converter, very fine rust needs to be present, and it needs to be surface rust.
it can help, but is it worth it?
I would rather just replace the control arm and ball joint after 10 years or so.
The frame did have a little surface rust from here and there. Though it tested it with a. Hammer and no crunching or anyhting on the *FRAME* atleast. The front of the transmission crunches when I even squeeze it with my hand. So yeah. I know the Rustoleum coats don’t cover the transmission but still.
If a part that commonly gets replaced has superficial rust I wouldn't worry about it. Instead of making a mess due to paint overspray, if it's not something exposed to excessive heat I just use something to clean the rust off, blow any dust off then wet it with oil.
As for everything else such as body or structurally significant parts, mask off what you don't want paint on (if brushing it on, there WILL be drips, runs j splatter that hit unwanted areas) sand it down to clean bare metal, then get to an appropriate grit, apply primer, sand that lightly, use tack cloth apply another coat or two then do a few coats of color, always sanding & removing dust/moisture/oil in between coats.
Finally you need a clear coat to seal your work. I skipped this step as a kid when I wanted flat black paint not knowing of ultra flat clear & I paid dearly since the paint absorbed not only all the moisture but also the road salt/dirt/oils & within a few months I had rust under the paint despite making it otherwise really nice.
So learn from the mistakes of others & not only prime but seal that paint once you apply it, never rely on a supposed "one & done" type cure all.
