[smokingfrog]

Also used for RR tracks.

http://www.weldpedia.com/2015/03/joining-of-rail-lines-by-thermite.html

[PA Engineer]

Yep. I used it for many years in engineering studies. It is very common in construction and electrical work. There is never a 100% burn and residue does come out of the molds. That is just cast into place. There is no arguing rationally with these people.