925 that won't tarnish

[flowerpecker]

hi there,
Is there anyway for 925 silver not to tarnish?

[BarryM]

925 silver is mainly an alloy of silver (92.5%) and copper (up to 7.5%) and it is the copper on the surface that tarnishes to a black film. Just polishing it off reveals fresh copper that will itself tarnish.

So the aim is to reduce the surface copper. This can be done by plating with pure silver, or more easily pickling the 925 ( which leaches out the surface copper and will turn the piece matt white) and then Gently polishing with a very fine polish such as jewellers rouge. This should significantly reduce surface copper and hence tarnishing.

I am a relative beginner but know a bit about metallurgy, some of the more expert silversmiths may be able to give you other methods.


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[mizgeorge]

A lot of large commercial producers will plate with fine silver to avoid tarnish (and to avoid doing a proper job of polishing as well). I think it's a sloppy option, and it will wear off.

If strong anti-tarnish properties are important to you, you might want to try a different sterling alloy - argentium is the obvious one, but Cookson's own Reflections Silver, whilst not quite as good IMO, does have better tarnish resistance.

Otherwise, storage is important. Keeping pieces stored in airtight boxes or bags and using anti-tarnish tabs both help a lot.

[enigma]

Do you know where you can get Argentium wire from George?
Im using Reflections atm as couldn't find Argentium.

[Dennis]

925 silver is mainly an alloy of silver (92.5%) and copper (up to 7.5%) and it is the copper on the surface that tarnishes to a black film. Just polishing it off reveals fresh copper that will itself tarnish.

So the aim is to reduce the surface copper. This can be done by plating with pure silver, or more easily pickling the 925 ( which leaches out the surface copper and will turn the piece matt white) and then Gently polishing with a very fine polish such as jewellers rouge. This should significantly reduce surface copper and hence tarnishing.

I am a relative beginner but know a bit about metallurgy, some of the more expert silversmiths may be able to give you other methods.


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Well, actually I have found that fine silver tarnishes too Barry. Rightly or wrongly I have put that down to the formation of silver sulphide. Dennis.

[mizgeorge]

Do you know where you can get Argentium wire from George?
Im using Reflections atm as couldn't find Argentium.

The UK supplier is now http://www.alliedgoldltd.com/3-argentium

Or from the US (usually Rio).

Such a pity that a British invention (once again) is so hard to get here.

[enigma]

Brilliant thanks George!

[BarryM]

Well, actually I have found that fine silver tarnishes too Barry. Rightly or wrongly I have put that down to the formation of silver sulphide. Dennis.

You are quite right that pure silver will still tarnish, but at a MUCH lower rate than 925. It may be caused by sulphides but the level of sulphur dioxide in the air (that creates the sulphides) is very low, particularly away from industrial centres.

[Nick martin]

Not a lot I can add to this topic other than what other members have said.

All I can suggest is doing what I do, and whether you're casting your jewellery, or producing it from sheet / wire, spend a fraction more and buy the reflections variation. I find that its a lot more resistant to firescale, and that it also comes out of the pickle really clean and without any firescale if dipped long enough. It also polishes up really well of course.

I've not used Argentium myself, but I believe thats a better option although I believe its good slightly different properties when heated that you need to be careful of... more brittle I think?

Cheers,

Nick

[flowerpecker]

brilliant guys,i learn a lot in my question.
Just in case i want to use Argentium do i need to buy a Argentium paste etc?