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Brass turning pink


#1

How to: I’m using brass (85%copper/15%zinc) after soldering and
pickling it’s pink, is there a way to have the piece remain or at
least return to the nice original gold color instead of this
pink/gold color? I have used a brass brush w/soap and water and also
hit it with the polishing marching.


#2

Hello: I found that brass gets that pink color when warm pickle and
warm rinse is used. So I use pickle and rinse with water at ambient
temperature.

Brass also gets a nice yellow color when pickling with cromic acid. I
have also cleaned that pink color with cyanide with good results
(Never mix cyanide with ANY acid).

Regards from Daniel Mischelejis


#3

try a mixture called “magic pickle.” into a teacup put 1/2 regular
pickle (just out of the pickle pot) and 1/2 hydrogen peroxide. put the
piece in the mix but keep an eye on it. it will remove the copper
plating from the surface of your piece but will etch the piece if it
is left in too long. when you’re finished just pour the mixture back
into your pickle. good luck… mj


#4
    How to:  I'm using brass (85%copper/15%zinc) after soldering
and pickling it's pink, is there a way to have the piece remain or
at least return to the nice original gold color 

G’day; Brass is usually composed of copper and zinc. When this is
heated a black colour is produced, which is mainly copper oxide
(cupric oxide). This dissolves in pickle, but some of the zinc
dissolves too, leaving the red copper colour on the surface. (call it
zinc depletion) A gentle abrading of this (tripoli, or 400 grit
wet-'n-dry paper) will remove the copper film and let you see the
brass again. Cheers, –

John Burgess; @John_Burgess2 of Mapua Nelson NZ


#5

Diane,

Sorry that this is a short post without extensive explanation, but
you will generally get this copper film because of the high
concentration of copper in the alloy. It is natural (without getting
specific). I have my students use a dilute solution of hydrogen
peroxide and sparex to remove the film. We have used a 50/50 mix most
often however I have advanced students who have experimented with a
70/30 sparex/peroxide mix. Don’t leave the piece in the bath for
extended periods of time, in my opinion not more than five minutes
before you check it. We have noticed considerable pitting in the
surface after extended exposure to the mixture. We often achieve
results within 1 to 2 minutes. Please remember to use this solution
in a well ventilated area as any mixture of compounds can lead to the
expulsion of gasses not meant for human inhalation. There are
additional people here on the Orchid list that can supply information
to you and I’m sure they will as they read your post.

Hope this helps,

Tim Glotzbach
EKU, Richmond, KY.