Note from teen-aged self:
Make sure when testing home-made black powder fuse (which is prone to sputtering and releasing glowing embers) that the lid is on the container of home-made black powder. The ensuring conflagration may just melt floor tiles. Fortunately a box fan in the window removed the fumes, and some artful smearing of the melted floor tiles restored things before the parents asked any awkward questions....

D.