Originally Posted by
cuyd
What about de-rusting with citric acid? I found it to be pretty cheap and afaik it's less toxic than other acids. I could make a makeshift container for frame and just fill it with water and acid then wait for few days. Seems I could just clean it with pressure water and no other chemicals, but would it be effective in de-rusting?
Also, people suggesting various methods but I found that most of them leave sort of slime left that has to be brushed off. Thing is, I won't be able to brush it off internal parts of frame and the only thing I got is pressure water. But pressure water might cause flash rust to appear...
Citric acid is unlikely to produce the results you want. It can even promote corrosion, especially in concentrated forms. You don't just want to remove the rust, you want to rust-proof the metal. Phosphoric acid is also a relatively weak acid, but does not promote corrosion of ferrous metals. It combines with iron oxides to form an insoluble iron phosphate. The process is called phosphatization, and is used to rust-proof ferrous tools, especially military equipment and firearms. Commercial phosphatizing solutions are available and faster than phosphoric acid alone.
Any chemical agent that you use is likely to be hazardous to one degree or other. Read and follow safe handling procedures