Comment: The horseshoe shaped beam and the beams melted in a cross...

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The horseshoe shaped beam and the beams melted in a cross...

...were not aluminum.

(see 1:58 & 5:17 for those in particular)
http://www.youtube.com/watch?v=PNtTcS2vrUg

This video is less than a minute and also shows molten steel.
http://www.youtube.com/watch?v=fNHNvwI-P9g