help needed with argentium discolouration

Hi I'm hoping someone out there can help.

I have used a piece of 0.5mm thick argentium for a small chasing and repousee piece. All seemed to be going ok but when I finished there were some small bits of red german pine pitch left in some of the very fine lines that I was struggling to get off so I decided to burn it off which went ok but the argentium went a grey brown colour, I have pickled this and it is now more silver in colour, but has a yellowy cast to it and a couple of small patches of dark grey! This is the first time I have used this and can find very little information about it, its certainly not the very white silver I was expecting.

Any ideas?

Thanks Carrie

Hi carrie, With any luck it will be either because you have some unburned deposits left, or because your pickle is loosing strength, or has become contaminated.

I would make up some fresh pickle.

Then reheat your piece in semi darkness until it barely barely glows, for a few seconds. Allow the heat to subside and pickle for no more than five minutes. Fingers crossed. Dennis.

You can expect discolouration when you heat argentium that has been freshly worked, abraded or polished, but it'll not go deep like firescale in traditional sterling, so will polish out easily. Once a piece is finished, you need to clean it well - ultrasonic ideally - then heat gently (100C for 3+ hours) to passivate the surface so it resists further oxidation. Quite a good place to start for understanding how best to work with argentium is here: http://media1.riogrande.com/Content/...cedures-IS.pdf - also (assuming you are using 935): http://media.wix.com/ugd/623923_4b2b...d0bebe1756.pdf
Alan

thank you both for your help, i will try polishing first and if that dosent work i will see if was my pickle like dennis says.

It's quite common for my argentium castings to come back with weird dark grey spots, but they polish off really easily and the silver then has a much nicer colour than sterling.
It's just a pain when the spots are in areas you can't polish easily!