Bill,
Funny you should mention pouring flour over a candle. In high school I blew  
the windows out of a gymnasium with two M-80's. The first one blew up the sack 
 of flour and dispersed it. The second one was rolled into the gym as we ran  
from the building. The explosion was deafening. It woke everybody within a 
ten  mile radius and managed to take out most of the chicken wire reinforced 
windows.  No, I was never implicated in this prank.
 
Rummy