That´s how the Wikipedia article on rust starts.
This watch was certainly in contact with water through the crown. The fund state made me doubt whether this watch would ever ticking again or whether it should migrate to the movements, which should serve as a replacement for future revisions.
But try is making wise and so the movement was first dismantled so as to examine more closely.
The winding stem was already out of the movement and when pulling the crown the stem met me completely. When I took of the hands and the dial it hit me hard. The entire winding staff around the clutch wheel and the winding pinion was one rust lumps.
When removing the cover plate has been clear that the ratchet wheel had lost two teeth. In my stash I had an incomplete movement of a caliber Junghans 620.02. This was declared as a stock of spare parts.
The Junghans 620 has an easily removable barrel. This version is specially mounted with two rubies and the upper bearing is easily removed by a small bridge.
Unfortunately it was not as easy as I hoped. When removing, the Rubin remained stuck on the rusted axis of the barrel and could be disassembled only by soaking the barrel axis in oil. There was a whole night in oil...
The cover of the ratchet was pinned in the deck board. In the attempt to remove this the next mishap happened: I tried to pull the plate from below where it broke me. It is better to drive it with the staking tool from above, which I did then (of course inevitably then also with spare parts).
The staking came again to use: The rubin of the barrel bearing had to be back in place. It was the first time that I put a ruby in his metal bearing and I can anticipate: The bearing did his work .
Usually I clean the surface of the removed parts with a small brush or Rodico and then in the watch cleaning machine. This nevertheless clearly rusty movement I decided it to be cleaned even in an ultrasonic bath.
Then the rusted parts were processed with a fiberglass brush and as far as I can polished.
Some parts were so attacked by rust that I was exchanging them.
The board and some parts were ground free up to the support material.
The winding stem was replaced and was to long, so it has to be shortened.
The dial of this Diehl watch is made of plastic and has a solar structure. The luminous material is thick and exalted applied to the figures. Unfortunately, this was distributed over a few places in the grooves of the structure of the dial. There I took this off carefully and cleaned the dial easily. The luminous material at least contains radiation tritium or even radium, so it is advisable to work always well protected, that is with mask, goggles and gloves.
Only cut the winding stem and the watch was already done! A hard but nice piece of work...