ask this old house
Q What was this tool used for?
A It’s an old-fashioned soldering iron, also called a soldering copper, after the pointy hunk of metal at its business end. You heat it up in a fire or with a blowtorch, rest it on a seam, then touch a stick of solder on one of the facets. The stick instantly melts into a silvery river that runs down to fill the seam.