Does rust converter spray actually work or am I going to do damage with it?
What is it supposed to “convert” the rust to? Rust is iron oxide, same as ore, and nothing short of a steel making process will turn it into anything else.
It could slow down further rusting. Rust should be repaired by cutting or grinding it out to bare metal and then doing a proper repair with brazing or using body filler. There are numerous books on how to do bodywork yourself.
Some say they’ve had successs using it to slow the process, but I’ve tried it and have been unimpressed.
Interestingly, I used a piece of aluminum flashing globbed on with generous blobs of “Liquid Steel”, to patch a rot hole in the bed of an old pickup, and it stopped the progress of the rust completely.
This stuff is popular and I’ve found it to be a worthwhile attempt to slow rust and in some cases act as a primer. I use if on heavier components (trailer hitch mounts example) and not much on sheet metal. That requires elbow grease and complete rust removal for a long term fix. But, even there, if your short on time and want to milk the car for another year, it’s worth a try. A long term fix, it is not. In areas underneath car on structural components, routinely (yearly) “painting” with red grease does wonders on exposed areas. Shutting off the O2 is the only real solution regardless of how it’s done.
Yes it works. But you must remove as much of the rust as possible either by grinding, sanding, or wire brushing. When the rust preventer is applied it destroys the remaining rust and leaves a durable polymer coating. This can be primed or painted. It will cause no damage.
Tester
The ones I used did not work well. Three months later, it’s rusting again.
Rust converter is supposed to convert iron oxide to iron phosphate. And it seems to – sometimes – if you follow the directions. Best and highest use is to prime slightly rusted metal that is hard to get to and mechanically scrape. It’s almost certainly not going to be effective on panels that are rusting through from the inside. Anyway, it’s probably not going to do any harm as long as you keep it off your hand rubbed lacquer paint job.
It works for a little while, but the rust will be back within a year.