Yellow gold turned pink

[Nhurst]

Please help. My assistant soldered her first batch of 9ct yellow gold and it has all turned pink. I have not seen this before.
Tried pickling (for a day!)
Tried hydrogen peroxide in pickle as I read on a web site some where. It has also been tumbled and I tried to polish it off.
No difference.
Anyone know what I can do?
Nicola

[caroleallen]

That sounds very strange to me. Have you tried sanding it down?

[Nhurst]

Can't do that as it all has very fine texture. They were castings

[Wallace]

have you tried using the 3m radial discs? They are flexible and won't take off very much, but will clear the surface a little. You can get really fine grades to use.

[Nhurst]

Does anyone know how this happened? Or a chemical that may get rid of it?

[Dennis]

Nine carat is likely to become copper plated electrolytically if iron gets into your pickle, particularly if it is well used, just like it does with silver. This could be due to iron filings, rusty flakes from the lid of your pickle pot, or the use of steel tweezers.

To be safe change to a new solution. Maybe heating gently and re pickling several times will help. Peroxide in pickle is said to work, but it needs to be fresh and strong.

As has already been said, medium grade radial disks will remove the film without being tough on textures, as it is likely to be very thin.

[philip]

I had this problem when I started melting 9ct to make my own bit and bods of jewellery, the problem was not enough flux (borax) was the answer. The copper in the gold oxidised and turned it pink/copper and this could not be altered except for re melting and using borax. Now I have nice yellow gold again not sure if this has happened in your case.