A safety coordinator at the Esso Oil Company plant in Longford, Australia, was using a belt grinder in his home workshop to smooth the edge of a hacksaw cut on a 2" length of 1.5" angle iron. He had been grinding for about 1.5 to 2 minutes when there was a loud "THUMP" accompanied by an approximately 2-foot diameter brilliant yellow orange fireball. The fireball lasted no more than 1 second and then completely extinguished itself. It completely enveloped the machine, his hands to half way up his forearms, and the front of his torso.I'll spare you the gory details. The guy got burnt a bit, needless to say. Good thing he was wearing his glasses, eh?
Now, what on earth makes a belt grinder explode?
Nothing on the bench was burning. A few streaks of white powder were deposited on the bench top and on a few items lying on the bench. The workshop was filled with dense white smoke with very little odor.Hmm, white powder? White Smoke? The plot thickens! One last piece of info is missing.
A few days before the event, the man's son had ground the heads off about twelve aluminum pop rivets.Aluminum makes a belt grinder explode? Yes it does my friends! Aluminum dust plus grinding dust from steel makes thermite. Add a bunch of heat from grinding sparks, and POOF goes your eyebrows. The good news is that thermite is very difficult to get going. This poor guy's loss of eyebrows was pretty fluky. But if you grind a lot of steel and a lot of aluminum...
So all you hot rodder slobs like myself who work with steel AND aluminum, get busy with the vacuum cleaner. The facial hair you save may be your own.
The "but am I paranoid enough?" Phantom