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Polishing sterling bangle


#1

In my experience sterling will be come harder, stronger after polishing, however from various goldsmiths I heard that is not correct, or if any hardening to be archived you would have to polish for hours. Who can enlighten me


#2

I can’t imagine that polishing would produce any substantial hardening of the metal. Hardening happens when the molecules of metal are compacted closer together. This happens mainly when it is hammered, stamped in a die or rolled through a rolling mill. Some of the tarnish resistant silver alloys can be heat hardened by holding them an oven at a certain temperature for a certain amount of time.
I harden cuff bracelets by bending them in a bracelet former that curves them in two directions at the same time. I buy the blanks in half hard sheet to begin with so they end up quite springy, for silver.


#3

Hi Wade,
I’m not going to disagree with the tarnish resistant silvers being the greatest thing since sliced bread, but I do want to point out that ANY sterling alloy can be hardened by annealing followed by an hour at about 575*F, not just Argentium or Sterlium or whatever. The amount of hardness gained seems to be similar, also. So many “alternative facts” around these days that I thought I’d speak up.
Best,
royjohn


#4

Yup, thats what the books say. Any sterling alloy can be heat hardened. But you cant heat harden fine silver.


#5

There are only four ways to physically work harden non-ferrous metals: rolling in a rolling mill, drawing wire through a draw plate, hammering (usually between steel hammer heads and steel bench plates–sometimes a hard plastic, like a delrin mallet will compress metal over steel) and lastly, by bending/twisting.


#6

You can also after you have worked your piece toss it into a tumbler.
Give it a nice shine too! (The Tumbler tosses the shot into the metal causing it to slightly harden. ) but for best results use a planishing hammer :hammer: to make it harder ever so slightly.


#7

That tumbling action has a realy minor impact on hardening metal.
The reason why is that the molecules and atoms deeper inside the metal stay
as they are… soft.
The only impact (as small as it is) is at the very top of the surface and
even that is of small importancy.

A blow of a hammer will penatrate the whole area changing the structure of
the metal, changing the hardness of the metal.

@bbbsimon.
I agree but you forgot one.
Precipitation hardening by heat is a well knowen way to harden metal but
not pure metals because there is nothing to precipitate.