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human
Why doesn't aluminium spark?

Hi guys, I was just watching some youtube video of Adam Savage and as he sands down some aluminium and it doesn't create any sparks.

I have never really noticed it before, can anyone explain why that is?
gpt
Because it's too soft.     Grinding sparks occur when two conditions are met, the metal needs to be flammable, which aluminum certainly is, and it needs to be hard enough for the grinding process to heat it up to the ignition temperature.  The harder the metal the more work needs to be done to grind it and the hotter it gets.  The idea formula is an alloy with rare earths know as mischmetal, very hard as well as flammable, used in lighter flints and such apps.