I did really need a spot welder though, and there was no shortage ... As the supercapacitors were roughly the shape of a large battery, I put a collar around one electrode as a spacer.

That need is what led [Erwin Ried] to purchase a small, battery-powered spot welder from a maker in Korea ... and is designed to be portable and powered by batteries commonly used for RC.

Want to make your own spot welder at home? This video shows you how to build a simple, functional spot welder using a battery ...