Fun fact: You can use a car battery, a set of jumper cables and a couple of straightened wire coathangers as an arc welding setup, just hook up one jumper lead from the battery to one of the pieces you're welding, and the other lead from the battery to the coathanger. The arc should melt the coathanger and the molten metal should hopefully weld your pieces together if they're close enough. Produces stuffty welds, runs out of juice quickly and may electrocute you to death, but it works in a pinch.