Removing fire scale

[Niamh]

Hi everyone
I’m making a pair of rose gold rings and one has got some kind of discolouration after soldering. I believe it’s fire scale. It’s a blackish tinge like spots in places on the gold I have tried filing it with 600 grit sandpaper, pickling, and polishing with tripoli but it’s not budging. Can anyone offer some advice please? Thank you

[Dennis]

I hesitated to reply, because I dont know. But if it happened to me I would heat the ring to just below red and drop it into strong hot safety pickle. Most blemishes dissolve after a couple of minutes, but you can repeat it several times.

Beware that it will spit and bubble up, so dont have your container more than half full, wear eye protection and step back. Dennis,.

[Niamh]

I hesitated to reply, because I dont know. But if it happened to me I would heat the ring to just below red and drop it into strong hot safety pickle. Most blemishes dissolve after a couple of minutes, but you can repeat it several times.

Beware that it will spit and bubble up, so dont have your container more than half full, wear eye protection and step back. Dennis,.

Thanks Dennis, I think it actually turned out to be firestain which was very hard to remove but i seemed to manage to remove it with a scotchbrite mop on a lowish speed x

[enigma]

I have had this on occasion and have used a Scotchbrite wheel then back through red and green everflex burrs but it is a pain so if re pickling works as Dennis suggests above its certainly worth trying first.
https://www.cooksongold.com/Jeweller...prcode-999-ACR
For future reference it tends to happen less when you coat the whole piece in Auroflux and also it seems to be a result of overheating the piece- the worst time for me was a large cuff that I had real trouble getting the solder to flow on before I had my Smiths torch.

[enigma]

Ha! cross posted there Niamh, glad it worked

[china]

coating in boric acid helps

[Niamh]

coating in boric acid helps

Thank you everyone, scotchbrite mop seemed to do the trick, although it took longer then expected to sort this out! I won’t be charging £280 for the pair of rings in the future!!!