This article is from the Pyrotechnics FAQ, by Hans Josef Wagemueller firstname.lastname@example.org with numerous contributions by others.
First though, here are some safety rules. Read these and memorize them.
1. Mix only small batches, especially when trying something out for the
first time. Some mixtures, particularly flash powder, will detonate
rather than deflagrate (just burn) if enough is present to be self-
confining. It doesn't take much to do this. Small amounts of
unconfined pyrotechnic mixtures may damage your hands, eyes or face.
Larger amounts can threaten arms, legs and life. The hazards are
greatly reduced by using smaller amounts. Also be aware that a mixture
using finer powders will generally behave MUCH more vigorously than
the same mixture made with coarser ingredients. Many of these mixtures
are MUCH more powerful than comparable amounts of black powder. Black
powder is among the tamest of the pyrotechnician's mixtures.
2. Many of these mixtures are corrosive, many are very toxic, some will
react strongly with nearly any metal to form much more unstable
compounds. Of the toxics, nearly all organic nitrates have *very*
potent vasodilator (heart and circulatory system) effects. Doses for
heart patients are typically in the small milligram range. Some can
be absorbed through the skin.
3. Keep your work area clean and tidy. Dispose of any spilled chemicals
immediately. Don't leave open containers of chemicals on your table,
since accidental spillage or mixing may occur. Use only clean equipment.
4. If chemicals need to be ground, grind them separately, never together.
Thoroughly wash and clean equipment before grinding another chemical.
5. Mixing should be done outdoors, away from flammable structures, and
where ventilation is good. Chemicals should not be mixed in metal or
glass containers to prevent a shrapnel hazard. Wooden containers are
best, to avoid static. Always use a wooden implement for stirring.
Powdered mixtures may be mixed by placing them on a sheet of paper and
rolling them across the sheet by lifting the sides and corners one at
6. Don't store powdered mixtures, in general. If a mixture is to be
stored, keep it away from heat sources, in cardboard or plastic
containers. Keep all chemicals away from children or pets.
7. Be sure all stoppers or caps, especially screw tops, are thoroughly
clean. Traces of mixture caught between the cap and the container can
be ignited by friction from opening or closing the container.
8. Always wear a face shield, or at least shatterproof safety glasses.
Also wear a dust mask when handling powdered chemicals. Particulate
matter in the lungs can cause severe respiratory problems later in
life. Wear gloves and a lab apron when handling chemicals. This rule
is very important.
9. Make sure there are no ignition sources near where you are working.
This includes heaters, motors and stove pilot lights. Above all,
10. Have a source of water READILY available. A fire extinguisher is
best, a bucket of water is the bare minimum.
11. Never, under any circumstances, use metal or glass casings for
fireworks. Metal and glass shrapnel can travel a long way, through
body parts that you'd rather they didn't.
12. Always be thoroughly familiar with the chemicals you are using. Don't
just rely on the information provided with the recipe. Look for extra
information - the Merck Index is very good for this, especially
regarding toxicity. It can also provide pointers to journal articles
about the chemical.
13. Wash up carefully after handling chemicals. Don't forget to wash your
ears and your nose.
14. If a device you build fails to work, leave it alone for half an hour,
then bury it. Commercial stuff can be soaked in water for 30 minutes
after being left for 30, then after 24 hours cautious disassembly can
be a valid learning experience. People have found "duds" from shoots
that took place over a year ago, having been exposed to rain etc,
which STILL functioned when fitted with fresh fuse or disposed of in
a bonfire. Even after a 30 minute waiting period (minimum), initial
pickup should be with a long- handled shovel.
15. Treat all chemicals and mixtures with respect. Don't drop them or
handle them roughly. Treat everything as if it may be friction- or
shock-sensitive. Always expect an accident and prepare accordingly,
even if all these safety precautions are observed. Several people on
the net have gotten stitches, lost fingers, or been severely burned.
Some of them were very scrupulous in their safety precautions and had
many years' safe experience with pyrotechnics.