This article is from the Pyrotechnics FAQ, by Hans Josef Wagemueller firstname.lastname@example.org with numerous contributions by others.
Ignitibility and Reactivity
The secret of making a good pyrotechnic mixture is _homogeneity_. The
better the contact with the oxidiser and the fuel is, the fiercer the
composition. Finely ground fuels and oxidisers are essential for good
stars and propellants. The required intimacy also implies that mixing
can never be thorough enough.
For consistent results, use the same sieves and same mixing methods. Wet
mixing is sometimes more efficient than stirring the dry composition;
moreover, it is almost always safer. Star compositions and granulated
powders can almost always be mixed with water or some other solvent.
Good, homogenous compositions also ignite more easily. Large amounts of
loose, fine powder of almost any pyrotechnic composition represent a
large fire and explosion hazard. But when such a powder is kneaded and
cut into stars or carefully pressed in a tube, it will take fire easily
and burn smoothly.
This is the pyrotechnist's dilemma: the best compositions are often the
most dangerous ones, too. But not always. There are chemicals and
compositions with much worse safety records than today's compositions
have. In the list of pyrotechnic chemicals below, the most notorious ones
have been indicated.