... as you forget and walk over hot gravel. It is fairly effective on all the small weed plantlets but forget it on dandelions.
You (may) be doing it wrong.
If you've got something like
this , you've got best part of 2,000c at full bore. That temperature kills the plant cells dead long before they burn, you don't need them to burn and disappear, all you need to do is wave it slowly and walk away, the soil/gravel shouldn't be getting too hot.
That's not the end of the story, because - pretty much however much you char the ground, it doesn't discourage Those Who Come After, which is why I've reverted to weedkiller for my block paving. 1 maybe 2 applications per year, as opposed to a 4-6 cycle of torching.
And of course, it is Teh Best Thing Evah !!!1! for lighting a bbq, 3 seconds and it's lit, 30 seconds and it's pretty much ready to cook.