Tinker

"[4] A tinker's dam is also reportedly a temporary patch to retain solder when repairing a hole in a metal vessel, such as a pot or a pan.

[5] In the Practical Dictionary of Mechanics of 1877, Edward Knight gives this definition: "Tinker's-dam: a wall of dough raised around a place which a plumber desires to flood with a coat of solder.

[4] When working with copper, tin, gold, or other low-melting-point metals, the tinker would construct a charcoal furnace out of bricks and mud.

At the bottom, he would leave a hole for the molten metal to pour out into a trough that led to a casting or a depression for an ingot.

The function of the blockage coined the term "tinker's dam" as being something that only lasted temporarily, as it was to be destroyed or made useless in the very near future.