Wirecutter tells us about cutting metals with it.
Today I’m going to talk about thermite.
Possessing thermite is not a crime as long as it’s not used or intended to be used in an illegal manner. It’s used for cutting metal or welding, so if you do any metal work at all you have a legitimate use for it. I do some lightweight metal working and have used it in the past to cut plate steel – what would take me hours to cut using a cutting wheel (not to mention about a million cutting wheels) can be done in minutes using thermite. It will not make a clean cut (lots of slag) but it beats the hell of changing cutting wheels every 3 minutes. Yes, you can accomplish the same thing by using an arc welder if you have one and cranking up the voltage but sometimes that’s not an option.”