Do you like welding? I like welding. My Dad was a fitter and welder who worked on big hydro projects around the world... Spain, Rhodesia, New Zealand, so it's got herioc connotations for me. Arc welding is a challenge to photograph. The arc is a dramatic source of hard light on the welder and the sparks add colour and action.
To get the spark streaks, you've got to have a nice slow shutter speed. I got this at 1/30 sec at f/8. The problem is that the arc can be so bright, either that part of the image is all burned out, or your welder can be way underexposed. If you're trying to get the arc in shot like this you may also have some serious lens flare to deal with.
I was pretty pleased to have gotten this on my first try. I have to confess to a little digital buggery to get some detail in those arc highlights, but nothing major.
There are also risks to this kind of photography. Those beautiful little sparks can seriously damage your lens or filter, and looking into this light for even a little while can give you a nasty UV burn that feels like sandpaper on your eyeballs. I remember my Dad would occasionally suffer that, and he was so inured to little burns that they seldom bothered him. Ah, the age of heroes.