[Don]

Hi.
I am from Kazakhstan
Sorry for my English.

Automation Engineer, My Hydroponics www.youtube.com/watch?v=HKO9VBg9B7A&t=11s

Two tons of St3 grade steel (similar to A284Gr.D, A57036, A573Gr.58, A611Gr.C, GradeC, K01804, K02001....), metal profile from 15x15 to 40x40 mm, length 6000 mm. I bought 50 kg of citric acid, monohydrate, 5 kg of zinc dust, built a bath 6.5x0.5x0.5 m.

Step by step:
- mechanical cleaning and degreasing with gasoline;
- washing with laundry soap, pH 11-12;
- rinsing under pressure with water (water is cleaned with a carbon filter);
- galvanizing in a bath (without galvanizing), filling with water / lemon / zinc - ratio 90 / 10 / 1.
Temperature 20C, time of day.
If I raise it to 60-70C, can I shorten the time?
Further -
- passivation with citric acid according to this technology
www.besttechnologyinc.com/passivation-systems/nitric-vs-citric-acid-passivation/
Temperature 20C.
- get a thin protective layer of 0.0..01 microns of chromium.
According to the link there 20 minutes, pH 2-3;
- drying.

 Do you think it is possible to apply an additional protective layer by passivation?
How effective will it be?
- after all, in theory, the first layer of galvanizing during passivation should decrease ...

Further -
I want to process welding seams in a galvanic way.
I will make soldering acid (zinc + phosphoric acid), a 12V power supply for electroplating.
Electrode with swab (soaked in soldering acid) for galvanizing the weld.
- this will be enough?