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Chemical reaction

Posted: Sat Dec 02, 2017 10:12 am
by carrie
Any chemists out there who can answer a question? I have quite a lot of silver jewelry that has become tarnished. I read on the internet that if you put it with baking powder a scrunch of aluminum foil and boiling water it will come clean. Well I have just tried it and it is brilliant, shiney, earrings, necklaces, bracelets the lot. The question how does it work obviously some kind of chemical reaction, what?

Re: Chemical reaction

Posted: Sat Dec 02, 2017 10:46 am
by Horus
Carrie, the reaction is because your silver jewellery has got itself a coating that is similar to rusting in metals like steel which is called Oxidisation. The difference is that silver combines with sulphur instead of Oxygen and so the top few atoms 'sort of' rust. Aluminium does a similar thing, but does it a lot quicker, in other words it will rust faster than Silver. So if you place the two metals together and then give them a method of transferring the electrons from your Silver to the Aluminium foil then that will happen and the silver will be shiny again. The baking soda makes the electrolyte (similar to how the acid works in a car battery) and allows the electrons to flow between the two metals so leaving one and attaching to the other, salt water would have done the same thing. ;)

Re: Chemical reaction

Posted: Sat Dec 02, 2017 11:02 am
by carrie
Thank you Horus, that accounts for the foil becoming discolored, clever chap. : :rs

Re: Chemical reaction

Posted: Sat Dec 02, 2017 1:15 pm
by Horus
You’re welcome Carrie and now if anyone asks, you will be able to blind them with science. :lol: :lol:

Re: Chemical reaction

Posted: Sat Dec 02, 2017 1:38 pm
by newcastle
The great advantage of the aluminium foil trick is that it simply transfers to the aluminium the offending sulphur atoms which , as Horus pointed out, creates the tarnish (silver sulphide). The silver atoms are left unaffected.

By contrast, cleaning fluids usually operate as a kind of abrasive. It removes the layer of silver sulphide (and thus some silver) - and a layer of silver itself if you're too enthusiastic. After a while of continuous cleaning with a fluid you can significantly erode the silver surface from electroplated items.

The aluminium foil is also much cheaper!

Re: Chemical reaction

Posted: Sat Dec 02, 2017 3:15 pm
by carrie
No doubt no one will ever ask me about cleaning silver, what a shame I could sound like the fount of all knowledge thanks to you two. :wi

Re: Chemical reaction

Posted: Sat Dec 02, 2017 4:16 pm
by HEPZIBAH
I'm glad the metal foil method has brought your silver up well. In future though, before using that method, try using a gentle soap and water soak and rub between your hands. This should keep silver looking good if it is not too badly tarnished in the first place.

Re: Chemical reaction

Posted: Sat Dec 02, 2017 7:53 pm
by Winged Isis
Yes, that's what Pandora stores advise and it works well on mine.

Re: Chemical reaction

Posted: Sat Dec 02, 2017 8:44 pm
by Horus
Basically you are talking about two things, one is a restorative cure (the foil method) in order to remove a contaminant from the silver and the other is a preventative cure by coating the silver with what is essentially fat and oil to prevent the contamination.

Re: Chemical reaction

Posted: Sun Dec 03, 2017 5:56 am
by newcastle
Soap and water is fine with removing dirt and grime but it's of limited value in removing tarnish as the oxides/sulphides of silver (and copper which silver items may also contain) are insoluble in water.

Moreover, the tricky bits - e.g. the insides of chain links - are difficult to access with finger rubbing.

Nevertheless, worth a try on lightly discoloured jewellery.

Dusak swears by the method and gives his crown jewels a regular scrubbing with hot water and soap ;)

P.S. If your jewellery contains pearls or gem stones, be aware that some cleaning methods might attack pearls or damage the adhesives.

Re: Chemical reaction

Posted: Sun Dec 03, 2017 5:34 pm
by Dusak
I was told that placing silver in coca cola gives a nice shine.

Re: Chemical reaction

Posted: Sun Dec 03, 2017 5:43 pm
by Horus
Dusak wrote:I was told that placing silver in coca cola gives a nice shine.
Works better on Copper ;)

Re: Chemical reaction

Posted: Sun Dec 03, 2017 5:46 pm
by newcastle
Dusak wrote:I was told that placing silver in coca cola gives a nice shine.
And if it's not real silver you can watch it slowly dissolve :wi

P.S. Have you tried it on your crown jewels? :lol:

Re: Chemical reaction

Posted: Mon Dec 04, 2017 5:12 am
by Major Thom
Pril dissolves the skin and gives you terrible inflammation that take years to get rid of. I used only a small amount to get rid of motorcycle grease. Should carry a strong health warning. When you think about it they use Pril with cold water to wash up, so it obviously has some strong chemicals in it. I may work with jewelry, who knows!

Re: Chemical reaction

Posted: Mon Dec 04, 2017 8:47 am
by Dusak
newcastle wrote:
Dusak wrote:I was told that placing silver in coca cola gives a nice shine.
And if it's not real silver you can watch it slowly dissolve :wi

P.S. Have you tried it on your crown jewels? :lol:
Not as yet, I will probably wait until the next shaving day, give a better run off, bit like a gutter and down spout. :up