science club |
How to polish a watch case
I have always been wondering how old watchmakers are able to polish
the case of a watch such that it looks almost like new.
There are companies such as replateit.com
who are specialized in galvanizing old watch cases but often that is
not even necessary. Just buffing the case will bring back it's old beauty
What you need
The procedure is very simple and you don't need any special machines.
A magic eraser sponge, a few cloth and the right metal polishing paste is
all you need. Metal polishing pastes contain abrasives (often diamond dust)
the size of a few microns. Those tiny abrasives mixed with a protecting
wax take away any oxidation and tiny grooves on the surfaces resulting
in an extremely even surface. This is what makes the metal shine.
Autosol metal polish.
I recommend to use autosol metal polish. You can find it in stores that
carry products for washing, waxing and polishing cars. To clean a watch
you will only need a tiny amount.
The basic idea
Metal polishing paste removes a little bit of metal from the surface
thus you should avoid to use it on gold plated surfaces. That is: you
should use it on a gold plated watch but only on the spots where the
gold plating is already damaged. The base metal (e.g brass or copper) matches usually the
tone and color of the gold plating. Thus if you clean the areas where
the gold plating is still good and you polish the oxidized base metal
in the areas where the gold plating is worn out then you can make it
shine again. Here is an example of a gold pated Bulova watch case. The
gold plating is partially damaged and even the gold plated areas look
dull because tiny cracks in the gold plating allow oxidation from
the brass in back to come to the surface.
An old bulova watch case prior to cleaning and polishing
An old bulova watch case after cleaning and polishing
The procedure: How to polish an old watch
- Take a "magic eraser sponge" (melamine foam sponge) make it a bit
wet and clean the entire watch case (rub hard). This will remove most of the
dirt and oxidation and make the areas shine where the surface level gold
plating is still good.
- Rub the watch dry with a towel
- Apply a tiny amount of "autosol metal polish" to and old but clean piece of cloth. Buff the areas where the gold plating is damaged. The cloth will become black. There is no rotating buffing wheel required. Just the cloth and your hand going over the surface a few times will do the trick.
- Take a clean white cloth and remove the black metal particles that remained after the polishing.
- The watch looks now clean and shiny but there are still some micro abrasives on the surface. Take a new cloth and a bit of mineral oil (e.g baby oil) and polish the watch. You will notice that the cloth becomes still slightly gray as tiny metal particles and dirty micro abrasives stick to the oil.
- Take now a soft microfiber cloth and buff the entire watch
Practice with a coin
I suggest to practice with a copper brass or nickel coin before you
go to your precious watch.
Testing autosol metal polish on a coin. A coin before and after polishing.
© 2004-2019 Guido Socher