[TheForge] Nickel patina... a guess...

[Andy Vida]

Looking at the results of the application of nickel-ox on wrought iron,
I am suspecting that two of the components may be nitric acid and copper
sulphate.

I am getting a coppery sheen on some pieces.  Copper sulphate leaves a
layer of pure copper on the surface of steel/iron (or is that copper
acetate?).  We used to use this t plate copper onto furniture at the
shop in Mesa.

Nitric is a common compoment in cold gun blues.  I'm thinking the black
oxide produced by the nitric combined with the reddish hues of the
copper
might well produce that purplish tone.

Anyone have any clue as the whether this makes a whit of sense?