Bismuth plating with dragondroff reagent onto Brass sheets. 

I also did not expect brass would I'm acidic conditions plate bismuth metal particles to brass. Copper electrode is negative and brass is positive.
5 g of Bismuth trioxide was added to 250 ml of 31% HCl, and then 2 g of potassium iodide was added, which made the dragondroff reagent.
The brass is less prone to corrosion than aluminum may have better contrasts.
when all is done, I will make a post on my RU-vid channel.
Warning: Hydrochloric acid is corrosive and toxic wear gloves and have a sink were you can wash it off quickly incase of skin contact. it can cause blindness at 31% if splashed into the eyes were PPE for that needed.
Reversing polarity making copper pos and brass negative coated the brass better in bismuth.
Bismuth salts and potassium iodide are toxic. Dipose of them properly.