As someone who (in his careless youth) built a very crude arc lamp, a couple of findings: 1) Such lamps generate a good amount of UV radiation. So wear good UV

As someone who (in his careless youth) built a very crude arc lamp, a couple of findings: 1) Such lamps generate a good amount of UV radiation. So wear good UV-blocking eye protection! (discovered 'cause I didn't, in the first few runs). 2) Such lamps produce a good amount of ozone. 3) Some parts of the arc can indeed be very hot. Enough to melt pieces of glass, steel or even nickel. 4) What carbon rods are used matters a lot for how well it works. For example pencil leads had a tendency to 'explode' along their full length. Not fun! 5) Confirmed: it's a light source fascinating to look at. FYI: I used carbon rods pulled from those big 6V batteries. 'Socketed' in a base of lead. 220V AC with a 1..2kW electric heater in series as current limiter. Peak lighting power around [voltage over arc] = [voltage over series resistor] (so each taking ~110V in my case). Don't do this, kids. Just don't. It's really dangerous (although I survived long enough to write this post). We have YouTube now.