Why don’t we see many silver watch cases?
Precious metals like silver and gold were extremely popular throughout human history as a preferred material to make precious objects. Still, nowadays silver is seldom – if ever – used in the manufacture of watches.
The motivation for this lack of popularity depends on a phenomenon that happens with allthe silverware you come across – which regards also silver ornaments like jewelry.
When worn in contact to the skin, silver has the tendency of staining the skin and the clothes with a darkish mark. This was not an issue back in time, when people used to wear pocket watches, but when pocket watches migrated to the wrist, the effect of silver smudging the skin and clothes became quite evident.
Actually, the blackish, greasy smudges that form on silver and are released on the skin come from the copper present in the alloy that composes the silver case of your watch.
Silver is not only silver
Remember that this alloy is composed in percentage by the precious metal – for example, in an 0,800 watch, 80% of the material is pure silver. The rest is made by other metals, which help to strengthen the alloy a bit, as in its natural state, silver is quite soft.
Typically, the other metal used in silver alloy is copper. And copper suffers from oxidizing when in contact with your skin. The most common stains from silver are black and occur when the silver tarnishes due to a reaction with gasses in the air.
This was not an issue when watches were worn on the pockets, but became rather important when they migrated to the wrist and came in constant contact with the skin.
Watchmakers found other alloys that looked like silver, like argentan, know as German silver – but still, most of the metals used to make these alloys had this kind of effect, or had other issues, like being prone to giving allergies to the skin, like nickel.
One of the only metals that is inert – does not give allergies and does not change its aspect in time – is stainless steel. So, when the price of stainless steel became more affordable, and the technique changed as well so the production was easier, watchmakers started using it instead of the previous solutions like plated metals (gold-plating and chrome-plating).
The modern saver: rhodium
While silver might cause allergy issues, there is a metal which is currently used for plating, both base metal and other precious metals, and it is rhodium. It gives a luminous sheen and a great lustre, so much that it is often used on other alloys to give them this “precious” look. And lots of modern silver jewelry is rhodium-coated.
Rhodium, however, has some drawbacks. It is brittle and rigid, so you cannot use it by itself, and has a high cost – more than the famous “noble” metals (silver, gold and platinum). More, even if modern plating techniques are much better than old ones, in time rhodium wears off, exposing the underlying silver and presenting again the same old issues that it had before.
So, what to do if you have a silver watch and you want to avoid it smudging and staining your skin and clothes?
The use of clear nail varnish
Apply a layer of clear varnish on the metal where the watch touches the skin. The varnish will be invisible and form a layer that will impede the silver to contact your skin – and so, will not oxidize and smudge skin and clothes.
When you see that the smudging starts anew, it is much better to remove the layer left on the back case, and put a new layer of nail polish on: if you apply a new layer over an old one, you risk that it starts yellowing.
You can find much more about horology and its fascinating history in The Watch Manual, a thorough e-book that explains all the basics about watchmaking and its protagonists.