I had always thought...June 11 2012 at 4:06 PM
No score for this post
from IP address 126.96.36.199
Response to monday and whacha wearin'?
blued hands were invented by Abraham-Louis Breguet, the famous French watchmaker (he set up shop in Paris in 1775) since he used them extensively on the timepieces he made for European royalty (indeed, his associations with the French royalty "motivated" him to sit out the French Revolution over in Switzerland. The risk of having one's head severed from his body can be a powerful motivation!).
However, it appears that these types of hands were being used earlier on the more expensive timepieces such as the "Nuremberg Eggs" which were the spring powered / balance wheel regulated forerunners of the familiar and much thinner pocket watch.
Those early personal timepieces only had a single hand, the hour hand, and the time was set by manually positioning the hand on the dial. Needless to say, all of that touching of a steel hand with sweaty fingers could make it rust rather quickly. So early watchmakers were always on the lookout for methods of protecting their hour hands from corrosion. One option was to use brass hands, but brass is softer than steel and the square holes that mounted them on the ends of squared off pivot extensions could fail over time as external torque was applied to the hand in order to move it about the dial to set the time of day. A steel hand is a better option even though it is more prone to oxidation than brass.
Some of the early watchmakers tried "blueing" the steel used on the hands. This technique was already being used on such things as armor and firearms to improve their appearance and provide added protection against rust.
It had been found that certain alloys of carbon steel, when heated in a furnace, would turn a nice deep sapphire blue in color. The effect could also be achieved by immersing the metal pieces in various heated caustive soda solutions. The color came from a very thin layer of black oxide or magnetite, Fe3O4 that formed on the surface of the metal. This substance is more resistant to further oxidation than red oxide or ordinary rust, Fe203 which is hydroscopic and, upon soaking up water, swells a bit and begins to flake. Once the flaking takes place, fresh iron is exposed to the air and further rusting will take place until, eventually, the entire piece of iron will be converted to rust!
Unfortunately, blueing metal does not make it 100% rustproof and it is still necessary to apply a bit of oil to it to prevent moisture from penetrating the blue oxide layer.
High end watches dress watches nowadays often use the furnace blued hands on their timepieces that were made using the same techniques developed hundreds of years ago. I am noting, however, that on many of the lower end, mass produced watches with blued hands, they are apparently just putting an blue colored anodized finish on the metal. I guess there is noting wrong with this approach because it does produce a finish that is identical to what would be achieved with furnace blueing. However, I have also seen "blued" hands that appear to have been made by just applying a blue, somewhat irridescent PAINT to the hands. These look totally FAKE to me.
I think those early Timex watches with the blued hands were probably made using the electroplating technique in order to keep the cost down.
- BTW... - technoguy on Jun 11, 2012, 4:26 PM