I notice that the day/date wheels for the 18k model of both 3711 and 3713 have patina or become yellowish, but not for steel model, anyone knows why? Many thanks!
18 carats is not pure gold, it contains 75% of pure gold and 25% of other metals
By: PoyFR : October 22nd, 2020-23:26
this case it could be that from 25% of other metals, one of the metal used is dominant or high dosage of it (here probably copper) and helping this patina effect.
Very nice piece! And the patina effect is just lovely 👌🏼
By: Makilla : October 23rd, 2020-01:07
This is due to the copper effect. 18KT gold is mixed with silver and copper in order to make the gold harder and more wear resistant than pure 24KT gold.
On a water resistant watch of this age the 'patina', i.e. corrosion or contamination, on the day/date wheel would worry me. It shouldn't be there. [nt]