What metal are antique kettles usually made from?

Copper, overwhelmingly. It appears in 154 of the 190 titles on Sellingantiques, with brass a distant second at 33. Iron, bronze and painted tinware turn up only as single appearances, including one toleware kettle on its stand.

How old are most of these kettles?

The dealers' dating runs from 1800 to 1950, with 99 listings carrying a clean year. Much of it is broad: 41 say only "19th Century", 32 only "Victorian". A cluster reads as 1800 largely because a run of George III kettles was entered that way, so treat it as early nineteenth century rather than the year itself. A few samples go back further, including a Dutch brass tea kettle given as c.1760-80.

Why are fish kettles sold as planters?

The long oval shape suits a window sill, and dealers have leaned into it. Of the 23 fish kettle titles, about half are offered for flowers rather than fish. Wording such as "planter", "window cill planter" and "flower display" appears in the titles themselves.

What is a spirit kettle on a stand?

A kettle sold with its own frame and spirit burner underneath, so the water stays hot while it sits on the table. Twelve titles name the spirit element and 18 name a stand. They come in brass and in copper, sometimes on wrought iron. Dealers flag the burner when it's still with the kettle, using words like "Complete".

Are Japanese kettles part of this category?

They appear rarely and sit at the very top of the range. The samples hold two Edo-period sake kettles with cloisonné lids and a single Kyoto iron tetsubin, which is a Japanese cast-iron kettle.

How many kettles come up for sale?

Around 22 are listed in a typical year on Sellingantiques. Fifty-three different dealers have handled one, so most who carry them carry only one or two at a time.