ok. Fertan is made in Germany so thought maybe you used it. I have been using it over here for 30 years. love it. non toxic works better than the other converters
i've been using on bare metal to prevent flash rust. I mix 1/3rd fertan to 2/3rds water in a spray bottle. works great. I can treat bare metal and leave a parts outside for months if needed and they wont rust.