From: agbrooks@teaching.cs.adelaide.edu.au (Zoz)

Newsgroups: rec.pyrotechnics,news.answers

Subject: rec.pyrotechnics FAQ

Date: 22 Jan 1993 06:02:21 GMT

Organization: Massachvsetts Institvte of Technology

Message-ID: <pyrotechnics-faq_727682531@athena.mit.edu>

X-Last-Updated: 1992/12/22

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Archive-name: pyrotechnics-faq





                              REC.PYROTECHNICS FAQ

                              ++++++++++++++++++++





CONTENTS

========



1. Introduction - Welcome to rec.pyrotechnics



2. Reading rec.pyrotechnics



3. Posting to rec.pyrotechnics



4. Legal Aspects of Pyrotechnics



5. PGI - Pyrotechnics Guild International



6. Pyrotechnic Literature

  6a. Fireworks Literature

  6b. Fringe Literature

  6c. Net-Available Information



7. Frequently Asked Questions

  7a. Nitrogen Tri-Iodide, NH3.NI3

  7b. Thermite

  7c. Dry Ice Bombs

  7d. Smoke Bombs

  7e. Basic Pyrotechnic Devices

  7f. Terminator Bombs, MacGyver, etc.



8. Commonly Used Chemicals in Pyrotechnics





1. Introduction - Welcome to rec.pyrotechnics

=============================================



Rec.pyrotechnics is a worldwide newsgroup dedicated to the discussion of

fireworks and explosives, mostly concerned with their construction. The

readers of rec.pyrotechnics welcome anyone with an interest in the

subject, be they experienced or just trying to get started in the hobby.



If you are just getting started, try to get hold of as much information

on the subject as you can, and read it carefully. If it is explosives

you are interested in, make sure you read up on the theory behind

explosives. There is a lot of misinformation in movies etc. regarding

explosives, so it is important you get a good background from a reliable

source.



In the Pyrotechnic Literature section below are several books that are

must-reads for anyone serious about pyrotechnics. Try all your local

libraries - even if they don't have the books mentioned below, they are

sure to have some information on the subject. Remember, you can never be

too well-informed - it is *your* safety that is at stake, and not being

aware of all the aspects involved is extremely dangerous.



Pyrotechnics and explosives are not safe - factories have been destroyed

in the past, and they have access to the best materials and equipment,

and take the most stringent safety precautions. Some people on the net

have also been injured by accidents, and many of them had years of

experience and took extremely comprehensive safety measures.



Some knowledge of chemistry and physics is essential - if you didn't do

high-school chemistry, get yourself a chemistry textbook and read it.

Make sure you understand the basic principles involved for any

composition you might be making. It is a good idea to check a recipe out

with someone who is experienced in chemistry, to make sure you haven't

missed any safety aspect.



If you take the time to find out all the information, and put safety of

yourself and others as your highest priority, you will find pyrotechnics

an extremely fun and rewarding hobby.



2. Reading rec.pyrotechnics

===========================



Often you will see an interesting composition or method posted to

rec.pyrotechnics and the temptation is to run out and try it immediately.

However, sometimes information posted will contain errors, or omit

important safety aspects. Sometimes people will post methods that they

heard from some vague source, or that they think should work but haven't

tried.



Leave it for a couple of days to see if anyone on the net responds to it.

If not, get a printout of it and read it several times to make sure you

are completely familiar with it. If you have any questions or corrections

for an article, please don't hesitate to post. People on the net would

much rather answer a question that may seem "silly" to you, than to have

you get hurt.



3. Posting to rec.pyrotechnics

==============================



If you have a composition or a method that has served you well, please

share it with the net. Also if you have a question, people will be happy

to help you out with it.



However, please remember that you message is going to be read by a lot of

people around the world, many of whom may not be as familiar with aspects

of your posting as you are. Include all relevant safety information, for

example possible mixing and storage hazards, toxicity, expected behaviour

of the composition once ignited etc.



If you post something you haven't tried, be sure to make that clear in

your article. This is a good idea when asking questions as well - make

sure it is obvious that you are asking a question, rather than posting

something you don't know about and hoping someone will correct it.



Read through your article before posting it to make sure that you have

covered every aspect, and that there are no errors or ambiguities that

could cause people to interpret part of it the wrong way.



4. Legal Aspects of Pyrotechnics

================================



Chances are that many of the procedures involved in pyrotechnics are

illegal without a permit where you live. There are generally separate

laws regarding storage of chemicals, manufacture of fireworks,

manufacture of explosives, storage of fireworks, storage of explosives,

use of fireworks and use of explosives.



The laws regarding fireworks may also be split up in terms of the "Class"

of fireworks concerned - commonly available fireworks are Class C, while

the fireworks typically seen at displays will be mainly Class B, with

some Class C. Make sure you know where you stand in terms of the law in

your area, and get a permit if necessary.



Make sure that what you are doing will not cause any damage to other

people's property, and that there are no innocent bystanders that can get

hurt. There are plenty of laws relating to injury or damage to third

parties and their property, not to mention lawsuits. We don't want anyone

to get in trouble with the law because of anything here.



5. PGI - Pyrotechnics Guild International

=========================================



Pyrotechnics Guild International, Inc is a non-profit organization of

professional and amateur fireworks enthusiasts: builders, shooters &

watchers.



Membership includes a quarterly journal and an annual convention.



(Idaho (Fire) Falls, Idaho, 92)



For membership information, contact:



        PGI

        Ed Vanasek

        18021 Baseline Ave

        Jordan, MN

        55352



        You need either three reccomendations from random people or one

        reccomendation from a PGI member.  Dues are $25/yr., US.



Another newsletter is American Fireworks News, monthly, miscellaneous

news, technical articles, ads, $19.95/yr.



        AFN

        Star Rt Box 30

        Dingmans Ferry, PA

        18328





6. Pyrotechnic Literature

=========================



6a. Fireworks Literature

------------------------



These are extremely good books on the subject of pyrotechnics, and are

really a must-read for the serious pyrotechnics enthusiast. Many others

that are not listed here are also worth reading - check out your local

library, Books In Print, Pyrotechnica Publications etc. for more

references.



Conkling, John A.: "Chemistry of Pyrotechnics: Basic Principles & Theory"

(Marcel Dekker, New York, NY 1986. (ISBN 0-8247-7443-4).)



See also Conkling's articles in Scientific American (July 1990, pp96-102)

and Chemical & Engineering News (June 29, 1981, pp24-32).





Shimizu, Takeo: "Fireworks - The Art, Science and Technique", 2nd ed.

(Pyrotechnica Publications, 1988. (ISBN 0-929388-04-6).)





Lancaster, Ronald: "Fireworks, Principles and Practice" (Illus.) 2nd ed.

(Chemical Publishing Company Incorporated, 1992. (ISBN 0-8206-0339-2).)

The 1st edition is also available, and is much cheaper. The 2nd edition

only has about 20 new pages and some minor corrections, but is about

$50 more expensive.

Shimizu often directs people to Lancaster rather than giving the detailed

information himself.





Weingart, George W.: "Pyrotechnics" (Illus.)

(Chemical Publishing Company Incorporated, 1968. (ISBN 0-8206-0112-8).)





Davis, Tenney L.: "Chemistry of Powder and Explosives"





More references are available from Books In Print.



By far the best source for all books on fireworks is:



Pyrotechnica Publications

2302 Tower Drive

Austin, TX 78703 USA





6b. Fringe Literature

---------------------



These books usually deal with home-made explosives etc. more than

fireworks, and are usually dubious at best. Most are not worth buying,

especially if you are more interested in the pyrotechnics field.



Much of the information in them is inherently unsafe - many of the books

deal with field-expedient methods, and assume that some casualties are

acceptable along the way. If you want to try anything out of one of

these, it is a good idea to ask about it on the net or to someone

experienced in pyrotechnics or explosives.





"The Anarchist's Cookbook": this is in "Books in Print" so your local

bookstore should be able to get you a copy.  Alternatively, you can send

$22 (includes postage) to Barricade Books, PO Box 1401, Secaucus NJ 07096.

The Anarchist's Cookbook gets a big thumbs down because it is full of

inaccurate information.



"Ragnar's Guide to Home and Recreational Use of High Explosives": thumbs

down as it is even more inaccurate than The Anarchist's Cookbook.



US Army Technical Manual 31-210 1969 "Improvised Munitions Handbook":

The Improvised Munitions Handbook generally gets okay reviews; it

contains a whole bunch of recipes for making explosives etc. out of handy

chemicals. You can get it from several sources, gun shows, or for $5 from

Sierra Supply.



"Poor Man's James Bond Vol. 2": mostly a set of reprints of various

books, in small type.  It does have Davis' Chem. of Powder and Explosives

and what appears to be Vol. 1 and 2 of the Improvised Munitions Handbook

series. Vol. 1 of PMJB has a reprint of Weingart's book Pyrotechnics (?)



Here are some sources for the books.  Most of these places will send you

a catalog with related material.



Loompanics, P.O. Box 1197 Port Townsend, WA 98368.

This company sells a wide selection of fringe books on drugs, explosives,

war, survival, etc.

Catalog $5.



Sierra Supply, PO Box 1390 Durrango, CO 81302 (303)-259-1822.

Sierra sells a bunch of army surplus stuff, including technical

manuals such as the Improvised Munitions Handbook.

Sierra has a $10 minimum order + $4 postage.  Catalog $1.



Paladin Press, P.O. Box 1307 Boulder, CO 80306



Delta Press Ltd, P.O. Box 1625 Dept. 893 El Dorado, AR 71731



Phoenix Systems, P.O. Box 3339, Evergreen CO 80439

Phoenix carries fuse (50 ft/$9), smoke grenades, tracer ammo, dummy

grenades. Catalog $3.



U.S. Cavalry, 2855 Centennial Ave.  Radcliff, KY 40160-9000 (502)351-1164

Sells all kinds of military and adventure equipment.



Thanks to Ken Shirriff, Phil Ngai, Keith Wheeler, Charles Marshall, Gary

Hughes, and others.



6c. Net-Available Information

-----------------------------



The so-called "gopher files", a collection of 4 introductory files on

pyrotechnics, are available using a file transfer client called gopher.

The sources for gopher are available via anonymous FTP from

boombox.micro.umn.edu in the directory /pub/gopher/ .



You can see what it looks like by telneting to consultant.micro.umn.edu

and logging in as "gopher". The pyroguide is in the Gopher system under:



Other Gopher and Information Servers/Fun & Games/Recipes/Misc/Pyrotechnics



These files are quite a good introduction to pyrotechnics, including

information on the manufacture of fuses and casings.





"The Big Book Of Mischief 1.3", commonly abbreviated TBBOM, is available

via anonymous FTP from world.std.com, and has the file path:



obi/Mischief/tbbom13.txt.Z



This is generally a compilation of articles from many sources such as

'The Poor Man's James Bond' and from here in rec.pyrotechnics. This also

comes under the heading of 'Fringe Literature', as many of the items and

methods contained in it are of dubious safety and reliability.



7. Frequently Asked Questions

=============================



Below are descriptions of several things that are frequently asked about

on rec.pyrotechnics - they are not generally of much use in fireworks,

but they are here to cut down message traffic on these subjects which

have been covered many times before.



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

   a time.



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,

   DON'T SMOKE!



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.



7a. Nitrogen Tri-Iodide, NI3.NH3

--------------------------------



Nitrogen Tri-Iodide is a very unstable compound that decomposes

explosively with the slightest provocation. It is too unstable to have

any practical uses, but is often made for its novelty value.  Some books

describe uses for it in practical jokes etc. but in my experience it has

been far too unstable for this to be a feasible idea. Despite its common

name, the explosive compound is actually a complex between nitrogen

tri-iodide and ammonia, NI3.NH3 (nitrogen tri-iodide monamine).



Reagents:



Solid Iodine (I2)

Ammonia solution (NH4OH) - Use only pure, clear ammonia. Other solutions,

                           such as supermarket 'cloudy' ammonia, will not

                           give the desired product.





Place a few fine crystals of iodine in a filter paper. The best way to

make fine iodine crystals is to dissolve the iodine in a small quantity

of hot methanol (care: methanol is toxic and flammable. Heat on a steam

bath away from open flame. Use in a well-ventilated area.), and then pour

the solution into a container of ice-cold water. This will cause

extremely fine iodine crystals to precipitate out. Drain off the liquid

and wash the crystals with cold water. If this method is not possible,

crush the iodine as finely as possible.



Then filter ammonia through the iodine crystals. Use a small amount of

ammonia and refilter it, to reduce wastage. The smaller the pieces of

iodine the better the result, as more iodine will react if it has a

greater surface area. You will be able to recognise the NI3.NH3 by its

black colour, as opposed to the metallic purple of the iodine.



Reaction:       3I     +  5NH OH     --->  3NH I     +  NI .NH    +  5H O

                  2(s)       4  (aq)          4 (aq)      3   3(s)     2 (l)



When the NI3.NH3 decomposes it will leave brown or purple iodine stains.

These are difficult to remove normally, but can be removed with sodium

thiosulphate solution (photographic hypo). They will fade with time as

the iodine sublimes.





Safety aspects:



NI3.NH3: Despite the common misconception presented in many articles

         on NI3.NH3, it is NOT safe when wet. I have personally witnessed

         NI3.NH3 exploding while at the bottom of a 1000Ml plastic beaker

         full of water. NI3.NH3 can not be relied on not to decompose at

         any time. Even the action of air wafting past it can set it off.



         If you want to dispose of some NI3.NH3 once you have made it, it

         can be reacted safely with sodium hydroxide solution. NI3.NH3 is

         a potent high explosive, and should be treated with respect. Its

         power, instability and unpredictability require that only small

         batches be made. Do not make more than you can immediately use.

         Never attempt to store NI3.NH3.



         The detonation of NI3.NH3 releases iodine as a purple mist or

         vapour. This is toxic, so avoid breathing it. Toxicity data on

         NI3.NH3 is unknown, but I think it is safe to assume that eating

         or touching it would be a bad idea anyway.



Iodine:  Iodine sublimes easily at room temperature and is toxic -

         ingestion of 2-4g of iodine can be fatal. Make sure you are in a

         well-ventilated area, and avoid touching the iodine directly.



Ammonia: Again, use in a well-ventilated area as ammonia is not

         particularly pleasant to inhale. Ammonia is corrosive, so avoid

         skin contact, especially if using relatively concentrated

         solution. If skin contact occurs, wash off with water. Don't

         drink it.





7b. Thermite

------------



The thermite reaction is a redox reaction that produces a lot of heat and

light. In its usual configuration, temperatures can exceed 3000 degrees C,

and molten iron is produced. It is therefore mainly used for welding, and

by the Army in incendiary grenades.



There are many possible configurations - basically it is the reaction

between a reactive metal and the oxide of a less reactive metal. The most

common is as follows:



Aluminium powder, Al (coarse)   1 volume part or 3 weight parts

Iron (III) Oxide, Fe203         1 volume part or 1 weight part



A stoichiometric mixture will provide best results.





The powders are mixed together and ignited with a suitable fuse. Many

people use magnesium ribbon - I don't recommend this, as magnesium ribbon

is not all that easy to light, and quite prone to going out due to oxygen

starvation. A much better fuse for thermite is a common sparkler. The

mixture should be shielded with aluminium foil or similar to prevent

sparks from the sparkler igniting the thermite prematurely.



Reaction:       2Al    +  Fe O     --->  Al O     +  2Fe    +  lots of heat

                   (s)      2 3(s)         2 3(s)       (l)



The mixture can be varied easily, as long as the metal oxide you are

using is of a less reactive metal than the elemental one you are using,

e.g. copper oxide and zinc. Adjust the ratios accordingly.



Safety aspects:



Reaction: Make sure you no longer need whatever you are igniting the

          thermite on - the reaction will melt and/or ignite just about

          anything. If you ignite the thermite on the ground, make sure

          the ground is DRY and free of flammable material. If the ground

          is wet a burst of steam may occur, scattering 3000 degree metal

          everywhere.



          Be careful when igniting the thermite - use adequate shielding

          to prevent premature ignition. Don't get close to the mixture

          once ignited - it has been known to spark and splatter. Don't

          look at the reaction directly. It produces large amounts of

          ultraviolet light that can damage the eyes. Use welder's

          goggles, 100% UV filter sunglasses or do not look at all.



Aluminium: Chemical dust in the lungs is to be avoided. As always, wear a

           dust mask. Make sure the environment you are working in is

           dry - aluminium powder can be dangerous when wet. Fine

           aluminium dust is pyrophoric - this means it can spontaneously

           ignite in air. For this reason aluminium powder with a large

           particle size is recommended.



Iron Oxide: This is not directly toxic, but any particulate matter in the

            lungs is not good. Again, the dust mask is important.





7c. Dry Ice Bombs

-----------------



Dry ice bombs are devices that use pressure to burst a container,

producing a loud report and limited shock effects. No chemical reaction

is involved - the container, usually a plastic 2-litre soft drink bottle,

is burst by the physical reaction of solid carbon dioxide, CO2, subliming

into gas. As the CO2 sublimes, the pressure builds up and eventually the

container ruptures.



The method is very simple - some dry ice is added to the container, some

water is added (about 1/3-1/4 full) and the cap is screwed on tight.

Within a short time the container will burst, usually extremely loudly.

The water can be omitted if a longer delay time is required. It is

reported that these devices can be manufactured using liquid nitrogen

instead of dry ice, and no water. This is not recommended as the delay

time will be substantially shorter.



Safety aspects:



Device: NEVER use glass or metal containers! I cannot stress this enough.

        Dry ice bombs are extremely unpredictable as to when they will go

        off, and a glass or metal container is very very dangerous to

        both the constructor and anyone else in the vicinity. Plastic

        bottles are much safer because the fragments slow down quicker,

        and thus have a smaller danger radius around the device. Plastic

        fragments are still very nasty though - don't treat the device

        with any less caution just because it is made of plastic.



        There is no way to tell how long you have until the dry ice bomb

        explodes - it can be anywhere from a few seconds to half an hour.

        Never add the water or screw the cap on the container until you

        are at the site you want to use it and you are ready to get away.



        Never go near a dry ice bomb after it has been capped. If a dry

        ice bomb fails to go off, puncture it from long range with a

        slingshot, BB gun, by throwing stones at it or similar. Some

        indication of timing can be achieved by semi-crushing the

        container before capping - once the container has expanded back

        to its original shape it is no longer safe to be anywhere near.



        Don't forget that the temperature of the day and the size of the

        dry ice pieces will affect the delay length - don't assume that

        delay times will be similar between bombs. A hotter day or

        smaller pieces of dry ice (i.e. greater surface area) will create

        a shorter delay. Remember, even though no chemical reaction

        occurs you can still be legally charged with constructing a bomb.



Dry Ice: Humans will suffocate in an atmosphere with a carbon dioxide

         concentration of 10% or more. Use in a well-ventilated area. Dry ice

         typically has a temperature of about -75 degrees C, so do not

         allow it to come into contact with the skin, as freezer burns

         and frostbite will occur. Always use gloves or tongs when

         handling dry ice.



7d. Smoke Bombs

---------------



A relatively cheap and simple smoke mixture is potassium nitrate

(saltpetre) and sugar. The mixture can be used in powder form, but much

better results are achieved by melting the components together. The

mixture should be heated slowly until it just melts - beware of excessive

heating as the mixture will ignite. Keep a bucket of water next to you in

case the mixture does ignite, and peform the entire operation outdoors if

possible.



The mixture does not have to be completely liquid, the point at which it

has about the viscosity of tar or cold honey is about right. While it is

semi-liquid it can be poured into cardboard or clay molds, and a fuse

inserted. Once it cools and hardens it will be similar to a stick of hard

candy, hence its common name of "caramel candy".





Safety aspects:



Mixture: The mixture burns very hot. Don't go near it once ignited, and

         don't assume that whatever the mixture is contained in or

         standing on will survive. Try not to breathe the smoke as fine

         particles in the lungs are not good for them.



7e. Basic Pyrotechnic Devices

-----------------------------



Stars

-----



A star is an amount of pyrotechnic composition that has by some means

been fashioned into a solid object. These are the bright burning objects

you see ejected from Roman candles, shells, mines etc.



Usually the pyrotechnic composition is mixed with a binder and a small

amount of solvent to make a doughy mass which is then fashioned into

stars, although some use has been made of so-called pressed stars, which

involve the composition being pressed extremely hard into a mold with a

hydraulic press or similar, thus doing without the solvent.



The usual methods are to make the composition into a flat pancake or

sausage and cut it up into stars ("cut stars"), pushing it through a tube

with a dowel, cutting it off at regular intervals ("pumped stars") or

rolling cores of lead shot coated in fire clay in a bowl of the

composition ("rolled stars").



Cutting and pumping produce cubic or cylindrical stars, while rolling

produces spherical stars. Pumped stars are the most suitable for Roman

candles, because it is easy to get the correct width. The stars are often

dusted with a primer, usually meal black powder, to ensure ignition.





Shell

-----



The shell is a sphere or cylinder of papier mache or plastic which

contains stars and a bursting charge, together with a fuse. It is fired

into the air from a tube using a lift charge, usually black powder. The

time the fuse takes determines the height above the ground at which the

shell will burst, igniting and spreading the stars.





Rocket

------



A rocket consists of a tube of rocket fuel, sealed at one end, with a

constriction, or nozzle, at the other end. The burning fuel produces

exhaust gases, which, when forced out the nozzle, produce thrust, moving

the rocket in the other direction.



Solid fuel rockets can be one of two types - end-burning, where the fuel

is solidly packed into the tube, so the fuel can only burn at one end -

and core-burning, where there is a central core longitudinally through

the fuel, so the fuel can burn down its full length. At the top of the

rocket can be a smoke composition, so it is possible to determine the

maximum height ("apogee") of the rocket, or a burst charge and stars.





Lance

-----



A lance is a thin paper tube containing a pyrotechnic composition. These

are most commonly used in large numbers to make writing and pictures at

fireworks shows - this is referred to as lancework. The tube is thin so

burns completely away as the lance burns, so as not to restrict light

emission from the burning section.





Gerb

----



These are pyrotechnic sprays, often referred to as fountains or flower-

pots. They consist of a tube full of composition, sealed at one end and

with a nozzle at the other, similar to a rocket. Unlike a rocket, they

are not designed to move anywhere, so all the emphasis is on making the

nozzle exhaust as long as pretty as possible, with large amounts of

sparks, nice colours etc.



The sparks are produced by metal powders or coarse charcoal in the gerb

composition, with coarse titanium powder being the chemical of choice.

Gerb compositions in a thin tube set up in a spiral arrangement are used

as wheel drivers, for spinning fireworks e.g. Catherine wheels.





Waterfall

---------



These are similar to gerbs, but usually do not spray as far. They are

usually mounted horizontally in banks of several tubes, placed some

distance above the ground. When ignited, the effect is like a brilliant

waterfall of sparks.





Mine

----



These have a mortar arrangement similar to that for a shell, but are not

designed to send out a shell. The lift charge sends up a bag full of

stars and a bursting charge, with a short fuse set to spread the stars

relatively close to the ground. Because the bag has much less strength

than a shell, the stars are not spread as far, and the final effect is

that of a shower of stars moving upward in an inverted cone formation.





7f. Terminator Bombs, MacGyver, etc.

------------------------------------



The first thing to remember when watching pyrotechnics in movies, TV

shows etc. is that it is exactly that, not real life. There is almost

always no point in trying to extrapolate what MacGyver, for example,

does back to reality, with respect to pyrotechnics at least. Reese

making those bombs from supermarket supplies in Terminator was bogus,

as are pretty much any information on explosives you receive from

movies. Sorry.





8. Commonly Used Chemicals in Pyrotechnics

==========================================



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.





Aluminium, Al                   -- Fuel



This is used in many compositions to produce bright white sparks or a

a bright white flame.  There are many grades of aluminium available

for different spark effects. Most pyrotechnic compositions that involve

sparks use aluminium, e.g. sparklers, waterfalls etc.





Ammonium Nitrate, NH4NO3        -- Oxidiser



This is used very infrequently in pyrotechnics due to its hygroscopic

nature and the fact that it decomposes even at relatively low

temperatures. Even when dry, it reacts with Al, Zn, Pb, Sb, Bi, Ni, Cu,

Ag and Cd. In the presence of moisture it reacts with Fe. It reacts with

Cu to form a brissant and sensitive compound. It is best not to use any

bronze or brass tools when working with ammonium nitrate.





Ammonium perchlorate, NH4ClO4   -- Oxidiser



Used as an oxidiser in solid rocket fuels, most notably the solid booster

rockets for the Space Shuttle.  Using it in a composition improves the

production of rich blues and reds in the flames. As with any ammonium

salt, it should not be mixed with chlorates due to the possible formation

of ammonium chlorate, a powerful and unstable explosive.





Anthracene, C14H10              -- Smoke Ingredient



Used in combination with potassium perchlorate to produce black smokes.





Antimony, Sb                    -- Fuel



The metal is commonly used in the trade as 200-300 mesh powder. It is

mainly used with potassium nitrate and sulphur, to produce white fires.

It is also responsible in part for the glitter effect seen in some

fireworks.





Antimony trisulphide, SbS3      -- Fuel



This is used to sharpen the reports of pyrotechnic noisemakers, e.g.

salutes. It is toxic and quite messy.





Barium salts                    -- Colouring Agents



Used to colour fires green. several are used:





Barium carbonate, BaCO3         -- Colouring Agent, Stabilizer



As well as being a green flame-colourer, barium carbonate acts as a

neutralizer to keep potentially dangerous acid levels down in pyrotechnic

compositions.





Barium chlorate, Ba(ClO3)2.H2O  -- Colouring Agent, Oxidiser



Used when deep green colours are needed.  It is one of the more sensitive

chemicals which are still used, best to avoid if possible, but if used it

should be in combination with chemicals which will reduce its sensitivity.





Barium nitrate, Ba(NO3)2        -- Colouring Agent/Enhancer, Oxidiser



Not very strong green effect.  Used with aluminium powder to produce

silver effects. Below 1000C aluminium burns silvery-gold, characteristic

of aluminium-gunpowder compositions. Above 1000C it burns silver, and may

be achieved using barium nitrate. Boric acid should always be used in

compositions containing barium nitrate and aluminium.





Barium oxalate, BaC2O4          -- Colouring Agent



Sometimes used, generally in specialised items with magnesium.





Boric acid, H3BO3               -- Stabilizer



This is a weak acid, often included in mixtures that are sensitive to

basic conditions, notably those containing aluminium.





Calcium carbonate, CaCO3        -- Stabilizer



Used as a neutralizer in mixtures that are sensitive to both acids and

bases, for example chlorate/aluminium flashpowder.





Calcium oxalate, CaC2O4         -- Colour Enhancer



Used to add depth to colours produced by other metal salts.





Carbon black/Lampblack, C       -- Fuel



A very fine form of carbon made by incompletely burning hydrocarbon fuels.

Commonly used in gerbs to produce bright orange sparks.





Charcoal, C                     -- Fuel



Probably the most common fuel in firework manufacture, it is not pure

carbon and may contain in excess of 10% hydrocarbons. Indeed, the purer

carbon charcoals (e.g. activated charcoal) do not necessarily give better

results, and are very often worse than less pure grades. It is included

in the vast majority of pyrotechnic compositions in various mesh sizes

and grades, or as a component of black gunpowder.





Clay



This is an important material for making fireworks, not as a reagent but

to perform various practical applications such as blocking or constricting

the ends of tubes for crackers or rocket nozzles, or coating lead shot

prior to the application of star composition when making rolled stars.





Copper and copper compounds     -- Colouring Agents



Used to add both green and blue colours to flames:





Copper metal, Cu                -- Colouring Agent



Both the bronze and electrolytic forms are occasionally used, but easier

methods are available for the same effect.





Copper acetoarsenate, C4H6As6Cu4O16     -- Colouring Agent



Commonly called Paris Green, this chemical is toxic but used to produce

some of the best blue colours in combination with potassium perchlorate.





Copper carbonate, CuCO3         -- Colouring Agent



This is the best copper compound for use with ammonium perchlorate for

production of blue colours. Also used in other blue compositions.





Copper (I) chloride, CuCl       -- Colouring Agent



Cuprous chloride is probably the best copper compound for creating blue

and turquoise flames, and it can be used with a variety of oxidizers.

It is non-hygroscopic and insoluble in water, but it is oxidised slowly

in air.





Copper oxides, CuO/Cu2O         -- Colouring Agent



Used for many years for blues, but needed mercury chloride to intensify

colours. Seldom used.





Copper oxychloride              -- Colouring Agent



Occasionally used in cheap blue compositions.





Cryolite, Na3AlF6               -- Colouring Agent



Also known as Greenland spar, this is an insoluble sodium salt.  Sodium

salts are used to produce yellow colours, but as sodium salts generally

absorb water this tends to be a problem. By using cryolite this problem

is surmounted.





Dextrin                         -- Binder



Dextrin is a type of starch that is added to many firework mixtures to

hold the composition together. It is the most commonly used binder in

pyrotechnics.





Gallic acid (3,4,5-trihydroxybenzoic acid)



This is used in some formulas for whistling fireworks. Whistle mixes

containing gallic acid are generally the most sensitive of the whistling

fireworks, with high sensitivity to both friction and impact when used

with chlorates, but cannot be used with perchlorates either.  There are

safer alternatives for whistle compositions.





Gum arabic (Gum Acacia)         -- Binder



An example of the various wood-resin-based adhesives used to bind firework

compositions. Others used include Red Gum and Gum Copal.





Gunpowder



Black powder is the mainstay of pyrotechnics. At a basic level it is

a mixture of potassium nitrate, charcoal and sulphur. However, simply

mixing these ingredients together will not produce proper black powder.

It merely produces a much milder version, which itself is used

extensively in pyrotechnics, and is commonly called meal powder.



True black powder takes advantage of the extreme solubility of potassium

nitrate by mixing the very fine milled ingredients into a dough with

water, then using strong compression to force the water out of the

mixture, so that tiny crystals of potassium nitrate form in and around

the particles of the other ingredients. This produces a product that

is far fiercer than the simple meal powder.





Hexachlorobenzene, C6Cl6        -- Colour Enhancer



Used as a chlorine donor in coloured compositions that require one.

Rarely used, with PVC, Saran and Parlon being preferred.





Hexachloroethane, C2Cl6         -- Smoke Ingredient



The basic ingredient in many military smoke formulas. Not often used

with inorganic smoke mixtures, except those containing zinc.





Iron, Fe                        -- Fuel



The metal filings are used mainly in gerbs to produce sparks. Iron will

not keep well in firework compositions, and so it is generally pre-coated

with an oil/grease. One simple method is to add 1 gram of linseed oil to

16 grams of iron filings, mix, and boil off the excess oil.





Linseed oil                     -- Stabilizer



Used to coat metal powders in order to prevent them from oxidation, both

prior to use and in the firework composition. Polyesters are used in

commercial fireworks, but linseed oil remains an accessible option to the

amateur.





Lithium carbonate, Li2CO3       -- Colouring Agent



Used to colour fires red.  It has no advantage over strontium salts for

the same purpose.





Magnesium, Mg                   -- Fuel



Used to produce brilliant white fires. Should be coated with linseed oil/

polyester resin if contained in a composition which is not to be used

immediately, as it may react with other components of the mixture. The

coarser magnesium turnings are sometimes used in fountains to produce

crackling sparks. Magnesium-aluminium alloys give similar effects, and

are rather more stable in compositions.





Parlon                          -- Colour Enhancer, Binder



Parlon is a chlorine donor, and a key ingredient in many coloured stars.

It is a chlorinated isoprene rubber, chlorine content 66%. It interferes

with burning less than PVC or saran, and can be used as a binder. It

is soluble in methyl ethyl ketone (MEK) and partially in acetone.

Compositions made with parlon and acetone or MEK are nearly waterproof.





Phosphorus, P                   -- Fuel



Phosphorus is rarely used in pyrotechnics today, except for a few

specialized applications. It was used commonly many years ago, but as the

hazards associated with its use became known it dropped out of use.



Phosphorus comes in several forms, of which the red and the white/yellow

varieties were used. Red phosphorus (used in the strikers on the side of

matchboxes) is the more stable form, while white phosphorus (used by the

military in incendiary devices) ignites spontaneously in air, and must

therefore be stored under water or otherwise protected from the

atmosphere. Both forms are toxic.





Polyvinylchloride (PVC)         -- Colour Enhancer, Binder



PVC is a commonly used chlorine donor. It is not as good as Parlon for

this purpose, but is cheaper and more readily available. PVC is soluble

in tetrahydrofuran (THF) but almost all other solvents are useless.

Methyl ethyl ketone (MEK) will plasticise PVC to some extent, however.





Potassium benzoate, C6H5CO2K    -- Fuel



Used in whistling fireworks, in combination with potassium perchlorate.

It must be very dry for this purpose, and should be less than 120 mesh.





Potassium chlorate, KClO3       -- Oxidiser



Originally used very commonly in pyrotechnics, potassium chlorate has

gradually been phased out due to its sensitivity, in favor of potassium

perchlorate. Mixtures containing potassium chlorate and ammonium salts,

phosphorus or anything acidic are particularly dangerous. For this reason

mixtures containing potassium chlorate and sulphur are to be avoided,

as sulphur (especially the common "flowers" of sulphur) may contain

residual amounts of acid that can sensitize the mixture. In general,

potassium chlorate should be avoided unless absolutely necessary.



Chlorates have probably caused more accidents in the industry than all

other classes of oxidisers together. The reason lies in their sensitivity

to acids and their low decomposition temperature. When mixed with an

easily ignitable fuel, such as sugar or sulfur, chlorates will ignite

from a fingernail striking a wire screen. Moreover, sulfur is often

acidic, a fact that has lead to spontaneous ignition of sulfur-chlorate

compositions. If you intend to use chlorates, pay extra attention to

safety.





Potassium nitrate, KNO3         -- Oxidiser



A very common oxidising agent in pyrotechnics, potassium nitrate is one

of the chemicals you should never be without. From its essential use

in gunpowder to general applications in most fireworks, you will find

potassium nitrate used wherever a relatively mild oxidiser is required.

In fireworks it should pass 120 mesh, but can be used at 60 mesh. The

fine powder should be used as soon as possible after grinding or

milling as it will soon cake and have to be re-ground.





Potassium perchlorate, KClO4    -- Oxidiser



More expensive than potassium chlorate, but a better oxidising agent

and far safer. In almost all mixtures that previously required the

chlorate, safety factors have led to its replacement with potassium

perchlorate. It should be used in place of the chlorate wherever possible.





Potassium picrate



This is a shock sensitive compound that is used in some whistle formulas.

While safer than gallic acid formulas in this respect, care should be

taken to keep it away from other metals such as lead, because some

other metallic picrates are extremely sensitive.





Saran                           -- Colour Enhancer, Binder



Saran is another plastic chlorine donor. It is most commonly encountered

in the form of the cling wrap used to protect foodstuffs. It is slightly

soluble in tetrahydrofuran (THF) and will be plasticised by methyl ethyl

ketone (MEK).





Shellac                         -- Binder



Shellac is an organic rosin commonly used as a binder where a water-

soluble binder would be inappropriate. It can be bought at hardware

stores in the form of lustrous orange flakes, which can be dissolved

in boiling ethanol.





Sodium salts                    -- Colouring Agents



Sodium salts are sometimes used in place of the corresponding potassium

salts, but this is uncommon due to their hygroscopic nature. They rapidly

absorb water from the air, which can ruin a pyrotechnic composition.

In particularly dry environments they can be used without too much

trouble, and are therefore used in places like Egypt due to the relative

cheapness of some of the salts with respect to the potassium ones. Sodium

salts are also used as colourising agents, producing a characteristic

orange flame.





Strontium salts                 -- Colouring Agents



Used to colour flames a brilliant red:





Strontium carbonate, SrCO3      -- Colouring Agent, Retardant



Used often for producing red colours, and as a fire retardant in

gunpowder mixtures.





Strontium oxalate, SrC2O4       -- Colouring Agent, Retardant, Stabilizer



As for strontium carbonate, generally, but suffers from greater water

content.





Strontium nitrate, Sr(NO3)2     -- Colouring Agent, Oxidiser



This is the most commonly used strontium salt, because it provides the

most superb red colour available. Best results will be acheived if the

strontium nitrate is anhydrous.





Sulphur, S                      -- Fuel



Another basic fuel in pyrotechnics, sulphur is used in many pyrotechnic

formulas across the range of fireworks, most obviously in black powder.

It is recommended to avoid the common "flowers" of sulphur, as they

contain residual acid. If they cannot be avoided, a small amount of a

neutralizer such as calcium carbonate should be added if acid is likely

to present a problem.





Titanium, Ti                    -- Fuel



The coarse powder is safer than aluminium or magnesium for producing

sparks, and gives rise to beautiful, long, forked blue/white sparks.

Fantastic for use in any spark composition, especially gerbs.





Petroleum jelly (Vaseline)      -- Stabilizer



Very occasionally used to protect metal powders e.g. iron by coating them

with a thin film of petroleum jelly.





Zinc, Zn                        -- Fuel, Smoke Ingredient



Zinc metal is used in what are known as zinc spreader stars, which

produce a very nice effect that looks like a green glowing cloud. Also

used in several smoke formulas, due to the thick clouds of zinc oxide

that can be produced.





SPECIAL CAVEATS

---------------



AVOID:



Mixing chlorates with:  acidic ingredients

                        sulphur or sulphides

                        ammonium salts

                        phosphorus

                        pitch or asphalt

                        gum arabic solution.



Mixing picric acid with:  lead or lead compounds

                          almost any other metal.



Mixing ammonium nitrate with metals especially copper.



Mixing nitrates with aluminium WITHOUT boric acid.





Further Information

-------------------



Further information about these chemicals, for example chemical, physical

and toxicity data, can be obtained from the following books:



The Merck Index

The CRC Handbook of Physics and Chemistry

Ullmann's Encyclopaedia of Industrial Chemistry

Kirk-Othmer's Encyclopaedia of Chemical Technology



The information may be found elsewhere, but these are the most

comprehensive and readily available.





--*** Many thanks to Dave Pierson, Christian Brechbuehler, Ken Shirriff,

--*** Petri Pihko, Bill Nelson, Robert Herndon, Mike Moroney, Geoffrey Davis

--*** and others for their helpful comments, corrections, additions and advice.

--

     ______        _____________    ______________________          ______

    /\####/\      /            /   /                     /         /\####/\

   /  \##/  \    /_______     /   /    _     ______     /         /  \##/  \

  /____\/____\          /    /   /    / \    \    /    /         /____\/____\

  \####/\####/         /    /____\    \_/    /   /    /_______   \####/\####/

   \##/  \##/         /                     /   /            /    \##/  \##/

    \/____\/         /_____________________/   /____________/      \/____\/



                     agbrooks@teaching.cs.adelaide.edu.au

.

