Gold Filled, Rolled Gold Plate, Electroplating.

In the late 1800's in the U.S., the process of gold filled
and rolled gold plate was developed.  These processes
involved the fusing of two layers of gold with a middle
layer of suitable supporting base metal.  The metal is
fused into a laminate through the controlled application
of heat, time and pressure.

A gold filled case is usually 10k or better and is .003
(3 thousandths) of an inch thick.  Rolled gold plate is
10k or better and is 1.5 thousandths of an inch thick.
For watch cases the amount of gold varies from 25 microns
in the rolled gold plate to 50 microns in gold filled.
The gold is applied in a way to make it much denser than
it would be if electroplating.  Electroplating is easily
discernible because it is brighter and has the look of
costume jewelry.


Gruen - Rolex

Gruen in Switzerland took its famous # 877 doctor's
wristwatch movement and with slight modifications
manufactured it for the # 300/500 series Rolex Prince
wristwatch.

Copyright American Wristwatches, Five Decades of Style
and Design, by Edward Faber and Stewart Unger with
Ettagale Blauer.
(This is a great book for collectors - my opinion)

Tim Sweet
TIMEKEEPR2@AOL.COM
M.O.S.T (MY OWN SWEET TIME) WATCH COMPANY.
14002 Tuckey Lane
El Paso, TX  79927  U.S.A.
(915) 852-2409  (See my add in the MART)

Requests and comments welcome
enjoy