|First arc-melted sample.|
My friend Max Whitby sent me an email about an arc melting furnace he had seen at a university in England. It could easily melt even very high-melting metals, like iridium.
It seemed like a device I could approximate at home using some things I had lying around. The most important component was an old stick welder I inherited from the former owner of the farm buildings in my compound. I've never learned to use it as a welder (my modern wire feed welder is much easier to use), but it's an excellent source of brute electric current when you need it (up to a couple hundred amps).
After I got a nice big chunk of graphite from eBay, and some graphite electrodes from Farm & Fleet (my local farm supply store), I decided it was time to give it a try. The furnace at the university had a vacuum chamber built around it allowing for melting of reactive metals without oxidation or other contamination. I may go that route some day, but for a first proof of concept experiment I just did it in the open air.
I cut an approximately 2"x2"x1" block of graphite, hollowed out a cup in the middle, and clamped the ground electrode of the welder to it. Then I placed my metal sample in the cup, put on a welding helmet, and touched the graphite electrode to the sample. After a bit of practice, I could easily bring the whole thing to white heat in a couple of seconds.
Judge for yourself whether I was successful in melting the iron: This thing used to be a 7/16" hex nut.
Source: Theodore Gray
Contributor: Theodore Gray
Acquired: 27 April, 2003
Text Updated: 11 August, 2007