|Plasma cutter electrode.
Plasma cutters are really neat: You can cut thick steel using nothing but electricity and air. No acetylene, no fuel of any sort, just the iron burning in air. Jim uses one on our farm to make metal art. Here's a picture of the arc plasma as it's reaching out to the metal, a fraction of a second before the metal ignites:
Here it is just after the metal ignites:
The sound for this sample is the sound of this plasma torch: The quieter sound at the start is the sound of the compressed air blowing out of the tip before the arc starts. Then it ignites and becomes much louder, and towards the end shuts off again leaving just the air sound.
Oh, wait, I guess I should explain what this has to do with hafnium! Ed found out that in the center of the electrode for just about any air-based plasma torch there is a small button of hafnium! Very strange where you find these elements. I think the ones in our torch have such a button, but they are chrome colored and it's hard to see. I went to my favorite welding shop and asked to pick out one where the dot was most prominent. This one shows a nice color contrast. I had planned to pay for the tip, but I guess he thought it was such a strange request he'd just give it to me.
Source: Claudin Welding Supply
Contributor: Claudin Welding Supply
Acquired: 24 July, 2002