I need to reply to a few remarks. First, I agree with safety. I wear welders gloves and a face shield. Two, there is only one power cord and it is far from the molten metal. Most of the "cords" seen are water cooling hoses, and they too are not near the path of the sparks. I have been using this for several years and it is fine. Three, there is no crucible: it is a billet being held by a solid rod. I was asking about the crucible because I have also liquifed metal and want a better way to contain it. The ones that I have bought have all shattered from thermal shock. Finally, the title is a mistake. I was going to post something else, and then I left the computer. When I came back to finish the post I was thinking about crucibles and wrote about this subject. I only realized the mistake the next day. Sorry about that one.
I actually have a great way to measure the temperature, but I will release that information in a few days. It is inexpensive and has reasonable accuracy.