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video Clean Silver Tarnish with Simple Electrochemistry
How to restore old silver with aluminum foil or a battery by electrochemistry.
Old silver is often tarnished by a thin layer of silver sulfide that appears as a brown color. The silver sulfide can be electrochemically converted back into pure silver if a negative charge is applied.
To do this, first make a solution of equal parts baking soda and table salt (NaCl) and adding enough hot water until they dissolve. Then simply place a silver object in the solution and contact it with a large piece of aluminum foil. In a short time the silver will be restored.
A very cool way to do the same thing is to use a battery. Connect the negative end of the battery to the silver and the positive end to a large electrode, like a copper plate, and dip them both in the solution.
This process occurs due to electrochemical reduction of the silver sulfide to silver.
Special notes:
THIS ONLY WORKS WITH ELEMENTAL SILVER! This restoration method does not work with silvery things like stainless steel or chrome. So make sure the item you want to experiment on really is silver before trying this.
A low voltage battery is best for this experiment, around 3 volts. Higher voltages do not improve the process and may actually damage the item you're trying to restore. If you don't want to mess up, then just use aluminum foil and skip the battery entirely.
More cool science videos at http://www.nurdrage.com
Old silver is often tarnished by a thin layer of silver sulfide that appears as a brown color. The silver sulfide can be electrochemically converted back into pure silver if a negative charge is applied.
To do this, first make a solution of equal parts baking soda and table salt (NaCl) and adding enough hot water until they dissolve. Then simply place a silver object in the solution and contact it with a large piece of aluminum foil. In a short time the silver will be restored.
A very cool way to do the same thing is to use a battery. Connect the negative end of the battery to the silver and the positive end to a large electrode, like a copper plate, and dip them both in the solution.
This process occurs due to electrochemical reduction of the silver sulfide to silver.
Special notes:
THIS ONLY WORKS WITH ELEMENTAL SILVER! This restoration method does not work with silvery things like stainless steel or chrome. So make sure the item you want to experiment on really is silver before trying this.
A low voltage battery is best for this experiment, around 3 volts. Higher voltages do not improve the process and may actually damage the item you're trying to restore. If you don't want to mess up, then just use aluminum foil and skip the battery entirely.
More cool science videos at http://www.nurdrage.com
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You have to either use a metal that won't disintegrate, like platinum, or a substance that once disintegrated won't plate onto the silver, like graphite or aluminum or iron.
As far as the other method goes, the best substance to use in the water is lye, or sodium hydroxide. A 10% solution is what is recommended by conservators who do this type of restoration professionally (although to be honest, the preferred method nowadays is the electrochemical cleaning with the battery). But if you don't want to risk lye, which can be nasty stuff, sodium carbonate is better than sodium bicarbonate. I have to admit I'm a bit skeptical about the claims that a single dip of the tarnished object is enough, though. If it's anything more than lightly tarnished, it's going to take repeated dips with lots of changings of the aluminum foil.
you can research the concepts of electrochemistry and such in most first year chemistry textbooks.
I've tried heating, adding more water, more Al, more salt and more sodium bicarbonate. Nothing helps to clean that last little bit.
I tried with an egg when I got my silver bar, and it polished it magnificently using this technique... But not so well when it's been anodized...
Can you restore it with a battery and Al foil (instead of a copper electrode?)
And also it helps with moving products away from reactants a tiny bit.
Thats my knowledge at least.
2 cups water for each Tbsp of soda
First i suggest leaving the item in the solution for a longer period, sometimes it might take hours.
Then i recommend gentle polishing with toothpaste. I know it sounds odd but toothpaste has fine abrasives that will help remove the tarnish.