There are really only 4 processes for sticking gold to something, and only 3 of them are really old.
The forth, electroplating, came relatively recently, as plating gold is much harder than plating most other metals.
Of the other three, there is simply gluing gold leaf on (guilding in the artist sense), amalgamating (dissolving the gold in mercury and painting the metal, then cooking off the mercury, obviously not done much anymore) and rolling.
Rolling involves sandwiching a sheet of , say brass, between 2 layers of gold foil, and squeezing in rollers to bond them together, the result is filled gold plate.
filled gold wire is a bit more complicated to make, but essentially the same result.
Other than being thicker than electro plate, filled gold is also not porus, so persperation can't get to the base metal as easily...
Because of the time, labor, and expense, very little filled gold is made these days, probably not for the last few decades...
It will probably be another lost art in a few more.