Stripping of Gold is usually done by proprietary solution based on Potassium or Sodium Cyanide
Edward, Eltek 



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
Sent: Friday, February 06, 2015 2:09 PM
To: [log in to unmask]
Subject: Re: [TN] Stripping of gold

Potassium iodide is another gold etchant. No idea if it attacks nickel also.
If I find a little time, I'll go through the treasure trove of tech documents Inge dropped on us a few years ago. I know there's an article or two in there about which etchants eat what.

If there is no "magic elixir" for this job, maybe electrolysis? You'd have to tie all of the conductors together.

And finally, another alternative is to simply wash the board in SN100 solder, then wick it off. The tin in the solder will pull off all of the gold. Then getting the tin off should be relatively easy with the proper etchant. It is common to have tin strippers in pcb shops. 

Wayne

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Grossmann, Günter
Sent: Friday, February 06, 2015 3:27 AM
To: [log in to unmask]
Subject: [TN] Stripping of gold

Hi all

I need to strip gold from Ni on solder pads but Aqua Regina eats away the nickel as well. Has anyone got the formula for a chemical solution?


Best regards


Günter


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