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- Frequently Asked Questions (FAQS);faqs.089
-
-
-
- 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.
-