for a longer fuse you can also use a cigarette with the filter broken off.
a cigarette burning on it's own will provide about a five - ten minute fuse.
just a word of warning, case anyone doesn't understand this.
packets of dust scraped from sparklers and sealed up are bombs, and whenever you make a bomb you take your life into your own hands somewhat...
i.e if you loose life or limb it's your own stupid fault.