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Recommended phosphoric and zinc solutions for rust removal, metal etching preparation

2007

Greetings,
In restoring antique cars as a hobby, oftentimes I come across gas tanks with insides having various stages of rust. For the medium of lights stages, I would like to remove the rust, etch the steel, and provide a zinc coating to which I can apply a sealer.
Others have recommended phosphoric acid to remove the rust, and zinc phosphate as a substrate/primer for a sealer. What would be the recommended concentrations of these two solutions?

Thank you very much

Matthew Sacher
hobbyist - Downingtown, Pennsylvania, USA

Try 5% ammonium citrate (pH 3,5) as rust remover,then you can use 20 gm tannic acid [on eBay or Amazon]/15 gm phosphoric acid / 1 lit water solution(simple do it yourself rust converter [on eBay or Amazon] ). Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
2007