note: It is impossible to
give a finite set of rules that will assure your safety in pyrotechnics.
Described below you will find just some of the most important and common
('everyday') things that should always be kept in mind when handling pyrotechnic
compositions and chemicals. They apply to a wide variety of compositions.
But every composition is different. Some must be rammed or pressed
to work properly. Other will explode when rammed. Some must be wet with
water, others may spontaneously ignite when wet. Some mixtures are relatively
safe to use by themselves but are extremely sensitive when used together.
(A number of well known 'incompatible' mixtures and chemicals are also listed
below). The point is: remember and think about the rules below, they are
important, but realize any such list is inevitably incomplete. Accidents
happen even in places where every conceivable safety precaution is taken.
We don't guarantee your safety if you follow the rules below (also read
the disclaimer and our webserver
policy), but merely say it is wise to do so. It'll increase your safety.
SPL accepts no responsibility for persons harmed or injured
or for any damage caused by devices like rockets, igniters, propellants
etc. made on the basis of information presented on the following web pages.
Information presented herein is for informative purposes only. Also note
that although we have tried to give comments on safety aspects of the
described procedures, but we may have forgotten things or have been inconsistent.
Keep that in mind at all times. Use your common sense, and use more than
one reliable source of information before doing anything.
that said, a list of some generally useful safety precautions in no particular
smoke when handling chemicals or compositions. Keep of children and
sure you are familiar with all the properties of the compositions you
work with. Thoroughly test new compositions for sensitivity, stability,
compatibility with other mixtures etc., until you are absolutely sure
that the mixture is ok to use in your application and method of construction.
Find out as much as you can about other peoples experiences with a particular
that need to be finely powdered before use should be ground separately
in a clean mortar with pestle or a clean ballmill or tumbler. Keep separate
equipment for oxidizers and fuels. For cleaning equipment used for fuels,
a solvent or sand may be useful. NEVER GRIND EXPLOSIVE COMPOUNDS OR
only non-sparking tools. Make your tools from either: wood, paper, aluminum,
lead or brass. Other metals and materials may spark (especially steel
bags or wooden containers are good to use for storing mixed compositions.
Store compositions dry and cool. Avoid plastics, glass and metal. Avoid
storing compositions in general. Make as much as you will need in the
near future and keep no more in stock than necessary.
have large amounts of composition near you. If you must use larger amounts
of composition in multiple items, store the bulk of composition in a
safe place and bring only small amounts to your working place. Finished
items should also be brought to a safe place immediately.
contamination of chemicals and mixtures. Have separate tools for every
type of mixture (i.e. blackpowder-like mixtures, chlorates, perchlorates,
etc.) and clean them well with hot water and/or alcohol after use. It
is no luxury either to have different sets of clothing for working with
different mixtures. Wash them every time after use (dust collects in
the clothing). If you have the possibility, have separate rooms or better
yet: separate buildings for working with different types of mixtures/chemicals.
to 7: Keep a clean working place. Fine dust easily spreads all over
your working place. Keep chemicals in closed cabinets or in a separate
building. Mixtures should not be kept in the working place anyway (see
rules 5and 6).
adequate ventilation. This is especially important when working with
volatile solvents or (poisonous, flammable) powdered chemicals. Not
only can you get yourself poisoned, vapour or dust may also ignite.
aware of static electricity buildup. Ground your working table. Monitor
humidity and keep it above 60% as a rule of thumb. This can be especially
important in winter when preparing for new years eve (on the Northern
Hemisphere at least). Touch a grounded surface before you place things
on it. Touch other people before handing over compositions or finished
items. Wear cotton clothing, avoid synthetics (do not be tempted to
wear fleece clothing if your working place is cold in winter). Simple
things such as unscrewing a (plastic) bottle, unwinding some tape or
even moving your arm may accumulate enough charge on your body to ignite
a sensitive composition. The risk of static electricity is often underestimated
or even completely ignored by beginning amateurs in pyro, while it is
actually one of the major causes of accidents in both commercial/industrial
and amateur pyro setups.
proper protective clothing. A face shield, dust mask, heavy gloves and
a leather apron are minimal. Wear cotton clothing. Hearing protection
can be good but it also makes it harder to hear other people's warnings.
safety screens between you and compositions, especially when pressing,
ramming, sieving or in other ways causing frictions/shocks/pressure
prepared for the worst. Have a plan for when something should go wrong.
Have a fire extinguisher and plenty of water ready (excepting for mixtures
for which water would create a greater hazard than ignition). Think
beforehand of what might happen and how you could minimize the damage.
Know how to treat burns. Inform someone else so he/she can help in case
of an accident. Have a fast escape route from your working place.
location: The work location for compounding of low sensitivity propellant
should be a minimum of 25 meters from any inhabited building, with distance
to increase appropriately depending on the amount and type of material
being used. All materials must be locked in proper storage facilities
when not actually being used. Finished propellant/motors will be stored
in a proper magazine.
Keep the area where propellant compounding is being carried out, clean
and neat at all times. Oxidizers, powdered metals, and other ignition
hazards will be treated with appropriate care to minimize the danger
of accidental ignition, with special care taken to avoid "dusting" of
fine material. Never have more than one open container of chemical within
this area at any time.
Become familiar with the associated literature, including MSDS's for
each chemical used. Don't use "makeshift" chemicals, but instead will
obtain technical grade or appropriate/equivalent purity for propellant
compounding. Learn about chemical incompatibilities
and avoid them (examples: ammonium compounds with chlorate compounds;
aluminum and any nitrate). Never make substitutions simply to see "if
this works", but instead will engineer mixtures to meet the preselected
The initial phases of your work will be performed under supervision
of a knowledgeable person, one who has been properly trained in that
which you are doing. Your initial work will involve mixtures that have
been well characterized by others and have found to be minimally sensitive.
You will study regularly to learn more about the nature of your propellant
and motor work. A good book about safety in pyrotechnics and rocket
propellants is L.
Edward Jones' "Safety Manual for Experimental and Amateur Rocket Scientists".
Work with small amounts of materials. For well characterized minimal
hazard mixtures make no more than can be used within a reasonable length
of time. Uncharacterized experimental mixtures will be made initially
in quantity not to exceed one gram, until the mixture has been properly
characterized as to sensitivity and other hazard.
Work in compliance with federal, state, and local laws. The local authorities
having jurisdiction will be aware of your activities. For people living
in Switzerland look here.
Test the (impact and friction) sensitivity of mixtures using the smallest
practical amounts of the mixture. Carefully note and avoid any
mixtures that are unduly sensitive. Test any motor design at least three
times, by proper static test, before committing that motor to flight.
rocket motors will be constructed of materials properly selected and
engineered. Don't use makeshift materials. Each rocket motor will be
designed so that its failure mode is longitudinal, and testing of such
motors will be performed in a vertical mode until the propellant has
been properly characterized. Strength of the casing material itself
will be a minimum of 1.5 times the maximum expected stress.
Dispose of scrap material and flammable waste from your operations properly,
by remote ignition, on a daily basis or more often. Scrap and waste
will not be allowed to accumulate.
out any other procedures needed to minimize properly the hazard to myself,
to others, and to your surroundings.
combinations of chemicals lead to especially sensitive or instable mixtures.
There are many more of such incompatible chemicals/mixtures than listed
here but these are some of the more commonly encountered types:
and sulfur. Mixtures containing both are not
only very sensitive to friction and shock but are also known to ignite
spontaneously. The sulfur reacts with water and air to form trace amounts
of sulfuric acid. This will react with chlorates to form chlorine dioxide,
a yellow explosive gas that will ignite most flammable materials upon
contact. Addition of small amounts of barium or strontium carbonate
to chlorate based compositions is sometimes done to prevent buildup
of acid, even in compositions without sulfur. Many older texts on pyrotechnics
describe the use of chlorate/sulfur based compositions. Today, many
alternative and much safer compositions are available and there is therefore
no excuse for the use of chlorate/sulfur mixtures. This also means chlorate
based compositions cannot be used in items that also contain sulfur
based mixtures. For example: chlorate based stars cannot be primed with
black powder. Nor can a H3 burst charge be used with black powder primed
stars (or stars containing sulfur).
and ammonium compounds. Mixing these will allow ammonium chlorate
to form in a double decomposition reaction that takes place in solution
(moisture speeds up the process). Ammonium chlorate is a highly instable
explosive compound. It decomposes over time producing chlorine dioxide
gas (see chlorates and sulfur). Mixtures are likely to spontaneously
ignite upon storage or may explode for no apparent reason. An exception
seems to be the use of ammonium chloride and potassium chlorate in some
smoke compositions. According to Shimizu this combination is safe due
to the lower solubility of potassium chlorate (compared to ammonium
perchlorate). I personally would still use these mixtures with great
caution (or avoid them) since it seems inevitable that small amounts
of ammonium chlorate will still form. The lower solubility of potassium
chlorate will make it the -main- product in a double decomposition reaction
but not the -only- product.
with metals and nitrates. These mixtures show the same problems
as chlorate/ammonium compound mixtures. The reason is that nitrates
can be reduced by most metals used in pyrotechnics to ammonium. The
reaction rate of this reaction is increased by presence of water. Over
time (for example when drying) these mixtures may spontaneously ignite
or become extremely sensitive. The fact that ammonium forms in a relatively
slow reaction is treacherous. These mixtures are referred to as 'death
mixes' by some.
and nitrates. Mixtures of these compounds sometimes spontaneously
ignite, especially when moist. The mechanism is assumed to be as follows:
the aluminum reduces some of the nitrate to ammonium, simultaneously
forming hydroxyl ions. The aluminum then reacts with the alkaline products
in a very exothermic reaction leading to spontaneous heating up of the
mixture. This can eventually lead to ignition. The reactions take place
in solution and therefore moisture speeds up the reaction. The process
is usually accompanied by the smell of ammonia. Some types of aluminum
are more problematic than others. Stearin coated aluminum is generally
safer to use. The whole process can be prevented in many cases by the
addition of 1 to 2 percent of boric acid. This will neutralize the alkaline
products. It is best to bind such compositions with non-aquaous binder/solvent
systems such as red gum/ethanol. Since aluminum/nitrate mixtures are
extensively used it is important to be aware of this problem which is
why the combination is listed here.