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Ph down and hydrogen peroxide


#1

hi all

after reading a reading a post and seeing a comment for using ph down
mixed with hydrogen peroxide for “bright dipping”? what will that mix
remove and how much hydrogen peroxide should be mixed with the ph
down. now i know this might sound stupid but im gonna ask anyway, do
you just desolve x amount of ph down in x amount of water then add x
amount of hydrogen peroxide and what strength of peroxide do you
need, cant it just be the stuff from the local chemist or would i
need to get it from a chemical suppliers

i would be greatfull for any help and advise that anyone can give

regards
jason


#2

The original Hydrogen Peroxide Pickle paper is in the archives of
this forum. Adapted from an industrial pickle process in 1979-80 by
me in graduate school at the University of Knasas.

Bill
Reactive Metals Studio, Inc


#3

Jason, just make up a solution for pickling (PhDown, i.e., sodium
bisulfate or Sparex No. 2 – they’re all the same) and add some of
the drugstore hydrogen peroxide. To tell if it’s working, see if
tiny, tiny bubbles are rising from the surface of your work. Over
time, try adding a little more PhDown and/or a little more H202. I
also heat mine very gently to try to speed the process. Do not let it
boil! It’s a lot slower than using 50:50 nitric acid to bright-dip.

This is for removing the red cuprous oxide (the black cupric oxide,
and any glaze from excess flux, will come off in the pickle). Go into
the Orchid Archives for previous discussions on this.

Judy Bjorkman


#4

Judy,…

It's a lot slower than using 50:50 nitric acid to bright-dip. 

But a whole lot safer!!

Other more specific examples of what to do with this
solution…when heating brass, it often is covered by a layer of
copper (cuprous oxide). The solution will strip that right off and
get you back to the brass!

Cheers from Don in SOFL


#5
Other more specific examples of what to do with this
solution....when heating brass, it often is covered by a layer of
copper (cuprous oxide). The solution will strip that right off and
get you back to the brass! 

After repeated heating and pickling of brass the red surface is not
cuprous oxide but relatively pure copper. This is just like the
effect you get from repeated heating/pickling of sterling where you
"raise " the fine silver surface. What is actually happening is the
zinc in the case of the brass and the copper in the case of sterling
is more readily oxidized during heating and then the oxide is
dissolved by the pickle leaving and enriched surface of either
copper in the brass example or silver in the case of sterling. The
H2O2/ pickle is a much more aggressive mordant and it attacks the
metallic material removing the enriched surface and revealing the
bulk alloy underneath. It will leave a matte surface behind due to
this etching behavior.

James Binnion
James Binnion Metal Arts