Originally Posted by jackei
I found different kinds of rust inhibitor out there. Some say will turn rust into primer, some say contain 90% of zinc, some say will some how prevent rust magically. wonder which one works best on our cars? which one I should avoid?
One that comes highly recommended from the restoration folks is Loctite Extend 754 or SEI CPT-298. These are both milky-white coatings.
Phosphoric acid-based compounds such as Naval Jelly are used initially to deactivate the rust. This is necessary unless you are able to completely without question remove all rust from the area. Neutralize the phosphoric acid with a baking soda solution wash.
OTC Rust converter primer is usually some kind of tannic acid mixed with acrylic. Note that most of these dry black, so read the label.
Zinc primers with phosphatizing agents will neutralize rust and form a protective zinc phosphate layer along with unreacted sacrificial zinc in suspension. The only problem with this stuff is that it's not white, it's silver.