The truth is you can enamel just about any metal of the silver, gold, copper, steel, bronzes, aluminum brass types and of course cast iron. The trick is in the enamel make up it self, plus the binding agent, and of course the temp used to melt the enamel and length of time in the kiln.
Cooking pots called enamel ware either in white with red or blue trim, or the infamous blue ground pots with white spots or flecks also sold under a number of generic trade names stone ware, blue enamel ware etc.
The most famous items of the cast iron stuff are the old style cast iron claw foot bathtubs of yore.
Brass items are done in India and China. The use of brass is only if it is very high in copper and low in zinc. The temperature must be accurately controlled or the zinc tends to bleed out of the metal and the enamel will not stick to it, but tends to pop off the base metal. Jewelry and decorative items, made up of thin brass wires soldered to a non-brass base forming cells, that are then filled in. It is called Cloisonné the brass wires are held in place by the enamel.
If you care to some of the better books are
The art of enameling, by Linda Darty
Cloisonné Enameling and Jewelry Making by Felica Liban &Louise Mitchell
And the two original masters works.
Enameling by Kenneth F Bates
Enameling on metal by Oppi Untracht
The materials and techniques have improved vastly in the last 45 years since I did my first ash tray. They have enamels that you can use with Mapp torches and a wide assortment of low temp lead free enamels.
The gilding metal that has been mentioned has a melting point of 1935°F/1057°C so the flow temp of the enamel should be well below that.
:clown: