I bought this Rado Diastar 10 Diamaster about a year and a half ago. Rado made 2000 of these between 1968 and 1972. They came with a white, black or blue dial. They are extremely rare and can fetch about as high a price as a vintage Rado goes for. I bought this one off ebay for about 5% of the highest price I have seen one go for.
The lightweight fishtail is in terrible condition and the watch itself is covered in decades of grime. TC can sometimes stain from this much garbage. The day wheel is lazy and doesn't actually display the day properly. The dial looks black but is actually. The dial looks like faded black but is actually the transparent blue variety. It once looked like this:
I managed to acquire a NOS Diamaster dial which cost roughly as much as I paid for the watch. I did a swap about 8 months ago. I can't remember where I put the old dial but it came out looking similar to this Disatar 14 dial:
No problem. A quickie job.
During the swap I discovered that the day wheel was acting like it was because the dial spacer was missing and the entire surface of the day disc was covered in oil. I cleaned the disc and assembled the watch. I wore it once or twice but had not rebrushed the bracelet and had not put a new dial space in. I took it apart and then... left it. I finally got back to it this morning and here it is now:
The AS 1876 with pus button date advance:
PA110279 by hankblanc, on Flickr
This movement was used by Rado in the Diamasters and in the Diastar 8. It is notoriously finicky and is the only automatic movement Rado ever used that had an unsigned rotor.
P1012852_01 by hankblanc, on Flickr
I did not touch the caseback. It has never been polished and shows only moderate signs of wear. A clean with lemon juice and sea salt is all it got.
P1012848_01 by hankblanc, on Flickr
P1012846_01 by hankblanc, on Flickr
P1012845_01 by hankblanc, on Flickr
The tungsten case and the sapphire crystal both got a clean with a polishing compound and the case front is flawless. This is a bit unusual on a Diamaster. The flat surface on these monsters is huge and they often end up scuffed.
Thanks for looking.