This must have been discussed before but in spite of a few searches I couldn't find any summary topic on the different variations of solid gold and gold plating on vintage watches.
Here are the variations I found :
Solid Gold :
18k = 1/750
14k = 1/583 (thought I'd seen 1/485 ?)
9k - seems rare
Plated : there seem to be several variations on this, "Gold Filled", "Electroplated", "Rolled Golled" "SGP" (Seiko) : different terms for the same thing ?
Types of plating : 9K, 10K, 14K, not sure I've seen 18k
Thickness of plating : 20 micron generally, sometimes 40 micron
Can anyone shed some light on variations in plating and whether some are better than others? Obviously 40 is better than 20 micron and 18k solid gold is better than 14k solid gold, although 14k might be stronger ?