I am making a 20 mm wide closed textured anti-clastic sterling silver cuff for a customer (don't we just love this kind of custom orders ). First annealed it, turned black (of course), my pickle could only cope with 50% of the oxidation, I scrubbed the rest off with steel wool (I don't do a lot of silver so maybe my pickle is no good with it). Anyway...
Textured the strip with the rolling mill, then back to annealing before forming on a mandrel. It turned a dull red, but never oxidized, it looks like I am heating 999 silver, but it is not (not so soft, turned black first time, was marked 935 silver)
But when it was annealed and cooled, it looked like a powdery white, I scrubbed that off with water and detergent and it was good as new.
Does anybody have an explanation or idea? I don't mind not having oxidation, but somehow it is odd, or?
No...what you experienced is common. What's odd is that you never experienced it before or that you could get the powdery off with just soap...I use a brass brush...who knew...maybe mine will come off with detergent too?
I'd avoid steel wool too, I'd use it as only a last resort, I was taught to use brass wire brushes, that way it doesn't contaminate the pickle.
Why it happened? I know it's been explained to me...I hope I get this right. The first time you got an oxidized layer of copper to come to the surface and took it off with the steel wool. The second time the layer of copper was clean not oxidized. If you've ever done granulation this is the step to do that.
Ah, that is cool. Thank you for your explanation. Sounds logic. I did use a brass brush with the detergent (no break through here )forgot to mention it, but I still could not get it off, so I used steel wool as plan b.
No, I have never done granulation, still on my long to-try-out list. Not even sure what it is exactly, something with small balls (don't laugh now).
Post by salvatorepaul on Aug 12, 2015 1:13:50 GMT -6
Theoretically, oxidation requires oxygen, and in thr rare event you heated the piece so perfectly thar while the flame was brushing it you covered the item so well all the air which could reach the surface was consumed by the flame, you would avoid oxidation. And the white you saw was the fine silver rushing to the surface, leaving heavier elements that form the other .065 (your silver was Marked 935, that's Argentum, and that is common with that alloy)