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Copper plating on brass


#1

Could anyone please suggest what the best way to remove copper plating buildup on brass after many soldering in fabrication processes? Obviously sanding, but there are many nooks and crannies in this piece where that is not possible…Super pickle and what is that formula?
Thank you!


#2

Whats the best for one person isnt the best for another.
Given that, the std formula in industry for bright dip of copper based metals is as follows.
55% conc sulfuric
30% conc nitric
balance water.
Plus for half a uk pint(8fl oz) of this mixture 1 level teaspoon of salt. Sodium chloride.
This needs to be used as follows, with a fume hood or like I do with the kitchen window open ( s/steel sink just in front), house/hold summer fan behind me, cold water a slow trickle 1/2in
have the object on a nylon thread. Dip into pickle, wait till it fizzes. Brown fumes blown out of window, lift out, rinse under running water, examine. Repeat 2 or 3 times.
Put bright dip back in bottle ( blue coloured!)
rinse everything well under hot water. dry. Or, if your set up to do it, Wet scratch brush, by hand or with motor driven brush.
If your not up to using these chemicals there are other ways, not my knowhow.
Ted.


#3

Super pickle is a 50/50 mix of clean pickle and hydrogen peroxide. It works better warm. It should work pretty quickly so don’t leave items unattended. Once you’re done you can pour it back into your pickle pot. It has no shelf life.

Hope this helps,

Pam


#4

If anyone tries this formula that Ted
gave us, I would like to add this warning:
Always add acid to water, never add acid to water, it will explode.
“Given that, the std formula in industry for bright dip of copper based metals is as follows.
55% conc sulfuric
30% conc nitric
balance water


#5

Sorry Pam, but it doesnt help.
If you want to help can we please have the full chemical formula for your clean pickle. there will be lots of folk who might use the wrong stuff and get hurt.
Pickle can mean what you use to preserve onions!.
Ted


#6

One of the reasons many people don’t post is that they don’t enjoy being attacked with criticism. It would be far more civil to ask for clarification than to hit with condemnation.

I use a food grade citric acid in water as a pickle. 1/2c to 1/2 gallon of water.


#7

Pam,

I have heard about the super pickle stunt in several texts. The Hydrogen Peroxide super charges the pickle for about 1/2 an hour. Then it turns into water. I have done it a time or two myself with Sparex 2. But I still ventilated heavily when I did it. As I recall it worked well.

Don Meixner

---- Pam Farren orchid@ganoksin.com wrote:


#8

Hi Pam
I did say sorry and please, not everyone is clever enough to know what clean pickle is.
As for condemnation?, I thought I was handling your post with kid gloves on.
I wouldnt dream of quoting anything chemical without being specific for common duty of care principles.
Ted


#9

Thank you so much Pam6! Do you think this will remove the copper from my brass surface?

Barbara McFadyen
www.barbaramcfadyen.com http://www.barbaramcfadyen.com/
bnmcfadyen@gmail.com mailto:bnmcfadyen@gmail.com

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#10

Hi Barbara,

It should quickly remove the copper from your brass. Mix just enough to cover your piece. The solution works better warm. As Don pointed out ventilation is important, as it is for most activities in the studio.

Pam


#11

Sodium bisulphate and hydrogen
peroxide mixed 50-50 is usually referred to
as super pickle.


#12

Hi Richard,
Can you PLEASE be more specific as to the ingredients

  1. What concentration hyd perox? Not HTP surely?
  2. The sodiun bisulphate, a powder? liquid?
    a solution? what weight in gms to 1ltr water?
    As ive just crossed swords with a poster called Pam who also was vague saying super pickle assuming everyone knew what it was?
    For no other treason than if you quote chemicals you have to be detailed for safety reasons if nothing else.
    I await you technical data.
    Thanks
    Ted… ,

#13

This is how I’ve always done it. Take the lid off the pickle pot (I use swimming pool acid - 2 tablespoons to a pint of water) and add a good dollop of hydrogen peroxide. Put the metal in. Leave it a bit. Take it out.

Hydrogen peroxide is simply water that had an extra oxygen molecule added to it. The metal and the warmth dissociates this oxygen molecule and since it is “nascent” (oxygen molecules usually pair up) it is highly reactive. It’s a moderately weak oxidizer. It’s bleaching effect occurs because most oxides are white and as dyes and hair color oxidize they turn white.

I respect the “care” taken by some people but this procedure is more related to cooking that chemistry.

I expect to make quite a few people cross by my lax approach.


#14

HI Ted,

Standard H2O2 sold in the drug stores (chemists) here in the States is a 3% solution, not the ?6% or 12%? you see in the UK. Nearly harmless.
Sodium Bisulphate is just Sparex #2 (pickle) without the pricetag. It’s often used around here to adjust the PH in hot tubs. Only sold in granular form. Many of the metalsmith types buy it from pool suppliers as Sodium Bisulphate because (A) it’s loads cheaper than Sparex #2, and (B) it’s actually more pure. Go figure.

Americans almost never use Sulphuric pickles any more. For 90% of us, if you say pickle, you’re talking about some sort of sodium bisulphate solution, and the rest are probably using vinegar or citric acid.

That said, as someone who grew up in a chem lab, I agree with you: if you’re going to talk about chemicals, please be precise.

But to get back to the original question, yes, a 50/50 mix of fresh sodium bisulphate pickle mixed with drugstore hydrogen peroxide will get the pink oxide off brass. It’s a pretty aggressive solution, so keep an eye on it and get your piece out as soon as the pink’s gone. It’ll also go after silver soldered joints, so be careful it doesn’t etch your joints to the point where you can’t polish out the line. The peroxide is photoreactive, so the solution will start to lose effectiveness in an hour or two, and will just be normal pickle again by the next day. (The H2O2 just degrades back to H2O, and dilutes the bath.)
For whatever any of that’s worth.
Brian


#15

Morning Brian,
Ahaaaa, a sane voice replies to my lone voice in the wilderness!.
Thanks for the H2O" %. BUT!!! youve STILL not said how many tons, or ounces of the SBS you mix with water!!
How the hell am I supposed to guess it?As you so rightly say with chemicals one should be specific.
Especially as USA stands for" you sue all!" ive been told.
It only take some stupid person to mix up the chems incorrectly, forget they put it on the stove to warm up , return and lift the lid for it to explode in their face. Then who ever failed to give the correct recepie, will very quickly have some hard nosed lawers knocking on the posters door.
If that happened Id laugh my socks off.
Ted.


#16

HI Ted,

Errrr…it’s a ratio. There is no specific quantity, other than a 1:1 ratio between freshly mixed Sodium Bisulphate pickle and (American) drugstore H2O2.
As someone earlier in the thread noted, it’s much closer to cooking than chemistry. If you mix it with too much H2O2, it gets more aggressive, too little and it slows down. That’s the only reaction it has. Higher percentage H2O2 could cause heating reactions with brass, but not the wimpy stuff they sell in the stores around here.

Regards,
Brian


#17

Brian,
So, you mean like cooking, 1cup of dry powder to 1 cup of liquid ?
thats not a solution like mixing acids, its a paste? or is it still liquid?
Am I getting there?
Please confirm.
Ted.


#18

Ted, sodium bisulfate is mixed until it goes
into solution, liquid will not dissolve more
and granules fall to the bottom.
Using warm water helps dissolve the
sodium bisulfate as cold water takes
longer for it to dissolve.
Hope this helps.


#19

Thank you ALL for your help with this information! I mixed a clean pickle solution, and Drugstore Hydrogen Peroxide 50/50. Worked like a charm!

Barbara McFadyen
www.barbaramcfadyen.com http://www.barbaramcfadyen.com/
bnmcfadyen@gmail.com mailto:bnmcfadyen@gmail.com

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