From: agbrooks@teaching.cs.adelaide.edu.au (Zoz)
Newsgroups: rec.pyrotechnics
Subject: FAQ
Date: 17 Aug 92 21:35:26 GMT


                              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.

--*** Table of contents added

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.

--*** Fixed error in fireworks classing

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., 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).)


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.  Catalogs from most of these places
are likely to be interesting.

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, is available via email-request from brech@vision.ethz.ch.
Send mail with subject "Send Gopher Pyro Files" for these files, which
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 at kalikka.jyu.fi, or via email-request from
brech@vision.ethz.ch, subject "Send TBBOM". 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.

--*** Added gopher files info, and email-request address for both those
--*** and TBBOM. Many thanks to Christian for providing this service.

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

--*** In this section, I updated it with the fact that this is a complex,
--*** and fixed the reaction accordingly.

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 name,
the explosive compound is actually a complex between nitrogen tri-iodide
and ammonia, NI3.NH3.

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 small pieces of iodine in a filter paper and filter ammonia
through them. 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

--*** Added weight ratio

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: Aluminium dust in the lungs is very bad. The original Tin Man
           in the movie "The Wizard of Oz" had his lungs severely damaged
           by the aluminium dust used to colour his face. As always, wear
           a dust mask. Make sure the environment you are working in is
           dry - aluminium powder is 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
-----------------------------
--*** I have replaced the section that was here before with this similar
--*** one. This will be followed by a section on common pyrotechnic
--*** chemicals and caveats with regard to mixtures, which Petri is doing.

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 sporal 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.


--*** 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.