1139 lines
50 KiB
Plaintext
1139 lines
50 KiB
Plaintext
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 Durango, 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
|
|
|