Nickel Plating on PC card fingers

[oldtimmer]

I used AP to disolve the copper on the boards, leaving the gold fingers, but still have the nickel platting is still left on the gold foil. What is the best way to remove it? Nitric acid? or other. If it is left on the gold foil and disolved along with the gold when using HCl+CL, what problems, if any, will it cause when dropping the gold put of the solution with SMB?

There is just too much good information here on the forum that one could spend a month and not cover it all. Only problem that I am having is trying to find detailed information as in the above question.

Secnond question is were is a good place to purchase some DMG for tesing solutions?

Thanks.

 

[lazersteve]

Oldtimer,

Typically nickel gets dissolved in the AP solution as the foils are lifted.

Are you certain what you are seeing is nickel. If it is then it should dissolve in AP, or just straight HCl. If it is nickel it's best to remove it before you move onto HCl-Cl.

I can hook you up with a gram or so of DMG if you want to send me a PM.

Steve

 

[Harold_V]

If it is left on the gold foil and disolved along with the gold when using HCl+CL, what problems, if any, will it cause when dropping the gold put of the solution with SMB?

Like all other contaminations, it will be the source of lower quality gold, due to drag-down. While it is very desirable to dissolve gold that has been stripped as cleanly as is possible, if you find that you occasionally have gold from a dirty solution, a second refining will generally bring it right up to standards.

I took advantage of gold that was not very clean. Filings from the jeweler's bench were usually quite dirty, and yielded gold of questionable quality routinely. It was that gold that I melted to use as the added gold for evaporation. By doing so, it got processed a second time, yielding far better quality.

If you find you have gold that is not pleasing, it is very easy to re-dissolve before it is melted. Armed with that idea, it might be to your advantage to melt a small sample before melting an entire lot, so if re-processing is required, you avoid dissolving a solid button.

Harold