As an alternative, I REALLY like the look of mercury gilded silver
and copper like that seen on medieval enamels or central asian
jewelry. I know there are health hazards with dealing with
mercury. Can it be done safely in small quantities in a small shop?
Equipment needed to do so? My preferred price range is in the same
$500 ballpark to set up the capability.
Mercury gilding can be done safely in small, very small and only
infrequent, quantities. The best instructions are still Cellini's.
However, while fire gilding on a purely hobby scale will not likely
do you much damage if well ventilated, fire gilding for commercial
purposes, even if done safely, will run you afoul of various
environmental regulations. You would be producing toxic, heavy-metal
vapors and could be in for stiff fines.
Keep in mind what Cellini says, that it is best to leave fire
gilding to the people who do it for a living, as it is dangerous. He
notes that those who do fire gilding as their profession tend not to
live very long.