# Clean Nickel Silver



## Enthalpy

Hi dear friends!

Here are *interrogation and observations about bicarbonate and aluminum cleaning nickel silver*.

The item is my flute. It stayed some 40 years exposed to the air in a normally dry room, the last untouched 8 years were the worst. Supposedly banal nickel (or German) silver: variable Cu-Ni18-Zn27. Definitely no silver layer on it. The black patch is adhesive tape. The clean patches are unalloyed tin hold by unsupported acrylic tape, they look like new after 40 years. The covers where I put my fingers are the less corroded ones, so fingers clean nickel silver faster than they corrode it. The cleaner end at the headjoint (second longest joint) stayed fit in the main joint all the years.









The bath is what Internet rumours recommend for true silver:

1 litre boiling (microwave) water (tap).
2 tablespoons bicarbonate ("pure" from drugstore).
A piece of aluminium foil (supermarket, usually Fe+Si 0.5% to 1%) at the bottom.
Plastic container (feels and looks like polypropylene, meant for cereals).
Observations:

Aluminium fizzles in boiling bicarbonated water without the nickel silver, producing an odour known in electrochemistry.
Bicarbonate poured in boiling water bubbles shortly, and then the alu foil doesn't fizzle. Supposedly, a decomposition cools the solution excessively. So, bicarbonate before heat.
Action is within seconds, including from the foam. Dirtier places take longer, you guessed.
The setup loses its efficiency quickly. The alu foil tarnishes, the bath gets less transparent, the temperature drops.
Microwave and plastic container let re-heat easily. Wrapping paper and a lid conserve heat. An immersed resistor would help.
*Contact of nickel silver with aluminium makes no difference*. For the small cleaned portion of the head joint, I avoided the contact.
Aluminium is necessary.
The used bath didn't etch my fingers. No strong NaOH concentration formed.
Some places at nickel silver still needed short rubbing, which was inefficient before. A piece of old bedsheet worked with downpressure without any lotion.
















*Can you propose a reaction?* The usual "sacrifical anode" must be ba***cks. I vaguely suspect some aluminium hydroxide scavenges the corrosion layer at nickel silver. At heat, bicarbonate might etch aluminium like NaOH does. Or the bubbles do the job. They could be strongly reducing (hydrogen??), and somehow activated.

I must still clean the main joint and the keys (removed to clean the joints, reassembled, check the contrast) so I can experiment your suggestions. No lab here, not even a thermometer, that's home chemistry - but an ohmmeter yes.

And: your instrument, your risk.

Thank you!
Marc Schaefer, aka Enthalpy


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## Enthalpy

More observations:

The bicarbonate solution gets a bit alkaline over time at heat without aluminium, like pH=10 or 11 according to beetroot juice.

Alone, it does nothing against the scale on nickel silver.

An aluminium foil reacts in the solution without the nickel silver part. Heat and clean foil are paramount. The bubbles' composition is unclear. This new solution with the foil removed does nothing against scale. No effect neither with the foil at one bath's side and the nickel silver part at the other. And nothing happens with the part over the solution where the bubbles emerge.

*Only with the nickel silver part in the solution where the bubbles rise does the scale disappear*, about instantly. Contact with the aluminium foil changes nothing.









The composition of the bubbles is still unclear to me: carbon dioxide, carbon monoxide, hydrogen, a reaction product with water...? A lighter provided no clear answer.


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## Enthalpy

*It works with sodium hydroxide instead of bicarbonate*, so I believe the cleaning gas is hydrogen.

The hydroxide is sold to clean drains. 1g/L gave beetroot juice true yellow as for the boiled bicarbonate solution, which had pH>12 hence, maybe 12.5.

Again, the alkali did nothing to nickel silver, and only when boiling hot did it produce bubbles from the aluminium foil. The bubbles cleaned the flute joint end, with or without contact with the aluminium.









As the joint wasn't quite clean, I tried bicarbonate again, but it did nothing better than sodium hydroxide. Organic residues supposedly prevented the bubbles' action.

I repeat: your instrument, your fingers, your risk. Bicarbonate works equally well and is less dangerous than sodium hydroxide.

Marc Schaefer, aka Enthalpy


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## Enthalpy

My mistake: the outer face of my flute *has a silver layer*. So cleaning with aluminium foil and bicarbonate is just the usual operation. Below the silver, the body is grey, much darker than silver hence it shouldn't be the usual nickel silver, while at the bore and the tenons it's more yellow, less so than the usual brass, and there the reaction didn't clean the metal. A workshop complained the alloy is very soft.

Aluminium and bicarbonate didn't act at the keyworks, where I suspect a strong biofilm, nor against residues from adhesive tape. 7000 grit sandpaper worked there but it removed the silver layer much faster than expected. Metal tools scratched the parts. Bone had the right hardness, I shaped a scraper of it, but access in the corners was imperfect and lengthy. The best means, especially on keyworks, were *toothpaste and a toothbrush*. This can replace all other means I tried.

Marc Schaefer, aka Enthalpy


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## david johnson

Try some Brite Dip.


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## Enthalpy

david johnson said:


> Try some Brite Dip.


NO.

A forum read by hundreds of people is the wrong place for random suggestions dangerous to the instrument and the operator.


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