[R-390] CAD Welding

[Shoppa, Tim]

> What on earth is CAD welding and can I do it at home with some #22 wire
> and a few electric bulbs?

AKA "Exothermic Welding" or "Thermite Welding". There's a graphite
crucible and thermite, a lot of heat and sparks, and when you're
done you've got a weld.

Brand name that is getting mis-capitalized here is actually "Cadweld".

Where I work, we buy them by the tens of thousands not just for copper
wires but also copper-to-steel and steel rails. Yes, it is a
poor idea to store all your cadwelds in the same place. Many years
ago we had a bunch in a locomotive cab that caught fire; it took many hours
for it to cool down enough that demolition of the remnant slag could begin.

Tim.