Home-made fireball

[Ashore]

I ground some aluminium on a wheel and a grizzled old foreman told me, in no uncertain terms, that the aluminium fills the pores of the grinding wheel. When it heats up the expansion can cause the wheel to crack and self destruct at high speed. Either way results in pain and injury.

The same can occure with wood, have seen the remnants of a 6" wheel after a seaman replaced several hammer handles grinding the tops into shape and clogging the wheel then went to sharpening cold chisles , had to press hard cause the wheel wasn't working properly , all got hot and boom, blew a bloody great chunk out the front and side of the wheel but the lucky idiot wasn't hurt , came and complained that the grinder wasn't working properly and was shaking when it ran , yes he had run it again and tried to use the other wheel it was so out of balance I had to skim the rotor where it touched the case and replace all the bearings

[Shedhand]

BobL is right. Thermite does need an intensive heat source to "set it off". I used to use it when I worked on the Nullabor in the early '70's when the ANR were replacing the old 45lb rail track with 90lb. Damn hot stuff.