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Brass turns red after pickling


#1

How can I avoid heated brass become red color after pickle?

I asked plating company to plate brass ring. But some part of the
ring become redish color. I think it is because after heating brass,
I pickled the ring and it become red color. I polish the ring but it
is really difficult to clean detail part completely and it turned
redish color.

Are there any solution to avoid heated brass become red color? or
Are there any easy idea to clean red brass?


#2

In general, when you heat brass, it will become both red and black
(oxides of copper). The black oxide is easily removed by pickling,
exposing the red. The red oxide can be removed by “bright dipping” in
dilute nitric acid or (better but slower) in a mixture of PhDown and
hydrogen peroxide.

Judy Bjorkman


#3

I dont cast in brass but regularly use bronze. Since both are copper
alloys this might be why your metal is turning.

The pickle will turn yellow bronze alloys reddish if there is any
iron /steel in the solution. It chemically activates the copper in
the metal making it a surface barrier. Your pickle might be
contaminated from some iron. I keep a couple pickling mini vats
going. One with materials that dont matter, one for when I want that
effect. Some specifically that are iron free, including tongs or a
sieve/strainer for retrieving pieces.

Hard pickle will remove the copoer tint. Pickle with hydrogen
peroxide added to the solution.

Another silversmith friend referred to it as poor man’s plating.

Eileen Webb


#4

I am not sure if you got an answer to this yet, but try putting the
brassin a solution of white vinegar and fresh hydrogen peroxide. 2
parts hydrogen peroxide, and 3 parts white vinegar. I have it in a
small glass bowl on the bench, it does not have to be hot, and it
lasts a day or so. It will get very blue. Keep an eye on the piece,
because the solution will start to etch it.

I used to use the borax acid and alcohol on charcoal block, and it
was a mess. You may want your brass to be more pristine than I need,
so do whatworks best.

Roxy