A Brief Introduction to Pyrotechnics
"Pyrotechnics is the science of using materials capable of undergoing self-contained and self-sustained exothermic chemical reactions for the production of heat, light, gas, smoke and/or sound. Pyrotechnics include not only the manufacture of fireworks but items such as safety matches, oxygen candles, explosive bolts and fasteners, and components of the automotive airbag." - Wikipedia, the free encyclopedia.
Simply said, pyrotechnics is the science of using different chemicals to achieve different effects. These are heat, light, gas, smoke and / or sound. Sometimes single chemicals can achieve these effects, but usually they require mixtures of two or more chemicals to achieve these effects. These mixtures of chemicals are so called: "pyrotechnic compositions". The most frequent main components in a "composition" is an oxidizer and a fuel. These two components help each other to react, and this is how...
A fuel, lets take Charcoal for example, burns very slowly and slowly produces a moderate amount of gas, because there is not enough oxygen in the atmosphere to make it burn fast. If you put this element into a firecracker, it would not burn fast enough to produce enough gas that will blast open the firecracker from pressure. If you take an oxidizer, Potassium Nitrate for example, it will burn fast enough but will not produce enough gas to explode the firecracker. When you combine these two, however, the oxidizer will burn fast and act as an oxygen donor for the Charcoal, thus making the mixture burn fast and produce a large amount of gas in a short time. If you put these two components into a firecracker, they will work with each other and blast open the firecracker.
As well as oxidizers and fuels, there are also other components in pyrotechnic compositions. These are:
Binders - will help to bind a composition together. Useful when granulating compositions because the binder will hold the composition in small solid pellets after water is applied (or sometimes a mixture of water and rubbing alcohol). Is also very useful when making pyrotechnic stars for the same reason. Water is applied and the composition stiffens into a solid shaped pellet.
Colorants - colorants are chemicals that burn at different temperatures in a composition that make it's flame become a specific color. All sorts of colors can be made, such as red, orange, yellow, white, green, blue, violet, silver, golden, etc. Other colors can also be made by simply adding two different colorants to produce a new flame color, but you need to accurately mix specific amounts of each as it varies greatly.
Stabilizers - stabilizers will stop the unwanted reactions of two or more chemicals in a composition. A common example is when metallic fuels and nitrates forming amides. When this happens, there is a chance of spontaneous ignition. This can be prevented by adding a few percents of Boric Acid.
Chlorine donors - Used widely in color compositions (containing colorants). Chlorine donors will aid a colorant in a composition and increase the color intensity.
Catalysts - these chemicals are used in rocket fuels to make it burn faster and more stably. An example of a catalyst is Iron (II) Oxide.
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Pyrotechnic compositions are only the basis of pyrotechnics. The next step is pyrotechnic devices. A pyrotechnic device is the scientific term for fireworks. Compositions made can be used in these pyrotechnic devices, both in loose form and in solid pellets called stars.
Stars are pieces of solidified composition that were dampened by water (and 1/4 parts rubbing alcohol mixed with the water) They are then kneaded for a long time into a very uniform clay-like mixture and then cut, rolled, or pumped (these are the types of methods used to make a star into a shaped pellet).
Making cut stars is probably one of the more easier methods. It is when you take the dampened composition and then lay it into a square shaped flat layer on waxed paper. Afterwards, you take a straight, sharp and thin object (usually a ruler) and cut a grid into the composition. Then it is let to dry in a cool and dry area. When it is completely dried it is taken and broken up where the dividing grid lines are, this leaves you with cube-shaped stars.
The second method is rolling. This is when you take a star roller, which is a small circular container that is rotated at a medium speed by a electric motor. Some slightly humid composition is put into the container along with a "core". The machine is started and the humid composition will cling on to the core and gradually build up (sort of like a snowball). Bird seeds are mostly used as cores. If the composition is not clinging on to the core, a tiny more water is added with a water sprayer. These rolled stars are left to dry and you are left with pretty much circular stars.
The third method, pumping, is when you take some dampened composition and pump it with a star pump. This is a tube with a bottom connected to a handle. You take the tube and press it onto the dampened composition and press it out with the handle, and let it dry. After this you will have a cylinder shaped star.
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Black powder, when used in a pyrotechnic device, is usually granulated to increase performance. Granulating is the process of taking the composition, adding +5% of a binding agent (typically Dextrin or SGRS) to the standard composition and making it slightly damp so it has a clay-like consistence. Then it is rubbed against a granulating mesh screen and let to dry on waxed paper. When dry, the small granules burn even faster as they use oxygen from between the granules in a pyrotechnic device. Black powder is the most commonly granulated composition, there are some others that can be granulated but that is usually unnecessary.
In pyrotechnics, compositions can be split up into several different groups. There are burst compositions, they are the compositions that produce a lot of gas in a little time. Useful for exploding pyrotechnic devices such as Firecrackers and Aerial Shells. There are also star compositions, these usually burn a specific color or produce some sort of effect (e.g. strobing, sparkling) and are used to make stars (which are later used in Aerial Shells, Mines, etc). Fountain compositions are simple mixtures of chemicals that are used specificly in Fountain devices. Usually these compositions are designed to produce sparks, colored flames, and / or crackling effects. The next group of pyrotechnic compositions are propellant comps. They produce a lot of gas but not as fast as Burst comps, ideal for propellants designed to lift a Rocket. These compositions do not burn fast enough for the Rocket to explode like a Firecracker (also known as CATO, catastrophic abort take-off). Sparkler and Flare comps are obviously used in sparkler and flare devices. Sparkler comps are designed to produce colored sparks and Flare comps are designed to burn with an intense colored flame, such as red, for signaling. Smoke compositions are compositions that produce smoke in smoke devices. Strobe comps are special compositions that require to be pressed into a solid pellet, like a star, to work. They flash with a colored flare and go out, only to flash again in the same color. This repeats itself until the composition is all burnt. These different compositions are used differently in pyrotechnic devices, each for thier own different property(ies). Burst comps are used for thier explosive properties, propellants for thier gas producing properties, stars for thier effects, etc. To see how the pyrotechnic devices work see these pages: Aerial Shells, Rockets / Missiles, Fountains / Gerbs, Firecrackers, Mines, Aerial Cake / Repeaters, Ground Spinners, Helicopters / Flying Spinners, Spinning Whels / Saxons, Roman Candles, Sparklers.
Now that you know about components (oxidizers, fuels, etc.) in a pyrotechnic composition, the different types of pyrotechnic compositions (Burst comps, star comps, etc.), and how the compositions are used you now have a basic overveiw on pyrotechnics. Visit the pyrotechnic devices pages to learn more and if you are unsure about some pyrotechnic term, see below.
Pyrotechnic Terms
Aerial Firework – any pyrotechnic device that is designed to function in the air (such as aerial shells, rockets, mines, aerial cakes, flying spinners and roman candles)
(spherical) Aerial shell – a very well known pyrotechnic device, it has a spherical shaped top that contains burst charge and stars and a cylinder shaped container on the bottom which contains lift (burst) charge. It is designed to shoot out of a mortar tube, propelled by a burst charge (called lift charge in aerial shells) and explode high in the air scattering lit burning stars.
Alloy - an alloy is two metals that are combined, usually to create a better chemical. An example is Magnalium, which is an alloy of Magnesium and Aluminium.
Atomic Pattern - when an aerial shell bursts and scatters three flat circular planes of stars that makes it look like the electrons around an atom. The arrangement of the stars within the shell is very important.
Barrage – a rapid repetition of an aerial effect, such as a roman candle.
Battery - a single kind of pyrotechnic devices that are binded together in such a way that they ignite at the same time or at slight intervals, such as an aerial shell battery or roman candle battery.
Battle in the Clouds – an aerial shell that releases several loud reports after exploding in the sky
Black Match – black match is a type of fuse that can be made at home simply by soaking a natural cotton string in a KNO3 solution and dipping it into a black powder slurry.
Black Shell (or blind shell) – a shell that fails to burst in the air because the fuse fails to ignite the burst charge. Blind shells will fall beck to the ground and might explode upon impact if the mixture inside the shell is too sensitive or if the burning remains of the fuse are knocked back inside.
“Blown Blind” – when the stars in an aerial shell fail to ignite because they were not primed (or primed with the wrong prime) or the burst charge failed to ignite them.
Bombette – a small shell that usually explodes with a loud bang and sometimes a flash. Used in aerial cakes and sometimes as inserts in aerial shells.
Bottle Rocket – a small rocket attached to a small stick that is usually propelled by whistle mix and ends with a loud crack in the sky.
Bounce – a small burst charge at the end of fountains.
Branching – when sparks split up into several smaller sparks that resembles branches.
Break – when a shell explodes in the sky, this word is also used for the burst charge in an aerial shell
Burst – when a shell explodes in the sky. The charge in the centre of the shell called a burst charge.
Burst Charge – the burst charge in the centre of the shell that breaks the shell.
Candle – another word for roman candle
Cherry Bomb – a powerful spherical flash powder firecracker made with a red casing and green fuse so that it resembles a cherry.
Chlorine Donor – a chemical with high chlorine content. Aids with colors produced from a composition
Choke – the part in a fountain that is designed to narrow down a flame and increase pressure, so that the flame shoots higher in a fountain.
Comet – a large pyrotechnic star usually designed to leave a dense, long-lasting tail.
Composition – a composition is a mixture of chemicals that will achieve some kind of effect, such as explosive, gas-producing, effects, etc.
Parralell wound Tubes– paper firewrok tubes that are made by winding paper paralelly, which produces strong tubes.
Crackle – multiples of small and sharp reports
Crossette – a type of star that burns for a short time and explodes into four smaller stars that burn for a moderate time
Crossmatch – technique used to ignite time fuse in shells. Blackmatch is glued onto the main time fuse to ignite the it easily.
Cut Stars – cubical stars that are made by using the cutting stars process.
Dark Fire (dark prime) – a special high-charcoal containing star that emits almost no flame as it burns. Used as a composition in between color-changing stars.
Daylight Shell – a shell that is designed to be visible in daylight.
Delay – a composition that is used as a delay as it burns slowly.
Detonator – a small easily-ignitable explosive that is used to ignite high explosives that need a start.
Dragon Eggs – Small micro-stars that, when primed with BP, burn for a brief moment and explode with a sharp crack.
Drivers – small rockets that power pyrotechnic devices such as spinning wheels.
Electrical ignition – when a pyrotechnic device is ignited by electrical means.
Electric Igniter (electric matches) – a device that is used to ignite compositions or devices by electrical means.
Fish fuse - a type of fuse that is filled with a very energetic composition that propells it around at random.
Flare – a device that consists mainly of a tube and a composition within the tube. It burns very brightly and is used in signaling.
Flitter - a star that leaves bright small flashes behind it, known as flitter.
Flowerpot – when an aerial shell explodes inside a mortar tube.
Girandola – a vertical spinning device that flies into the air and usually ends with a bang or stars.
Glitter – a tail effect consisting of bright flashes of light
Go-getter - a very energetic star composition that is able to propell a star by itself.
HDPE – High Density Polyethylene. It is used for mortar tubes.
Helicopter – a flying spinner that has "wings" that help it propell itself into the air.
Hummer – also called a ground spinner. It whizzes around with a humming noise.
Hygroscopic – a unwanted property of a chemical. It means that the chemical absorbs moisture from the air and becaomes moist.
Kraft paper – brown paper that is used in pyrotechnic devices
Ladyfinger – small firecracker
Lance – similar to a flare, it contains a composition inside a tube and burns steadily with a colored flame
Leader – the fuse that transfers fire from the day fuse/electrical igniter/flare to the lift charge of the shell.
Lift Charge – a burst charge beneath an aerial shell that shoots the shell upwards from inside the mortar tube, like a cannon.
M-80 – a small but powerful flash powder containing firecracker. It is illegal and is used in the military.
Mortar – a tube made from strong plastic that aerial shells are launched from
Multi-break – a shell that has several compartments and breaks at different times.
Prime – an easily ignitable composition that is mixed with a small amount of slurry and applied to stars, fuse, etc. to ensure ignition
Pulverone – the mixture produced by mixing the ingredients of black powder and not doing anything else to it
Pumped stars – stars produced by compressing damp composition in a cylindrical tube and cutting them at a specific length.
Punk – a stick of compressed sawdust that burns very slow, used for igniting consumer fireworks
Pyrotechnician – a specialist in pyrotechnics
Quick match – extremely fast burning fuse that can ignite anything at almost the same instant
Ramming Rod – a rod made of a non sparking material that is used to compress compositions inside a tube, to make a fountain, for example
Repeater – a device consisting of several other pyrotechnic aerial devices, such as fountains, candles, etc.
Report – an explosion
Rising Effect – things such as comets or whistle that are attached to the bottom of aerial fireworks as they rise into the air to give them a tail effect or other effect
Rocket – a pyrotechnic device that is propelled into the air by a propellant and usually ends with a report and stars
Roman candle – a pyrotechnic device that sends multiple burning stars into the air at a regular interval
Round star – a type of star (also known as a rolled star) that is spherical in shape and is made by rolling a humid composition in a rotation device that also contains a "core" such as a bird seed and the composition will cling on and form a circular star
Saltpeter – an alternative word for potassium nitrate
Salute – a loud report with no stars or effects but often a flash
Safety fuse – another term for visco fuse
Shell of Shells – a large shell that contains smaller aerial shells inside so that they burst after the large aerial shell bursts
Shot – a word used for the amount of stars usually in a roman candle (such as a five shot candle, etc.)
Silver Salute - a powerful and illegal firecracker similar to an M80 but is slightly longer and is silver in color
Smoke – Smoke is usually an incomplete burning of a organic substance
Snake - a small pellet that, when lit, produces black ash in the shape of a snake rising out of the ground
Sparkler – a pyrotechnic device that consists of a metal wire and a composition coating it on the top end. When lit it will burn and produce sparks as you hold it by the metal wire end
Spiral-wound tube – a tube that is made by winding paper with glue at an angle so that it forms a tube
Star – a small pellet of pyrotechnic composition that produces some kind of effect, such as a colored flame or sparks, etc.
Star gun – a device used to test pyrotechnic stars. It has a small lift charge at the bottom of it and has the star on top. The lift charge is lit and the star will be shot from the tube.
Star pump – a kind of tube with a flat bottom with a small handle that is used to produce pumped stars. You compress the dampened composition into the tube and pump it out with the handle and you will be left
Strobe – a solid pellet that flashes repeatedly when lit
Time fuse – a type of fuse used as a delay in aerial shells
Titanium report – a type of report with silver sparks that are caused because of titanium metal in the composition
Tourbillion – a device that spins round, similar to ground spinners
Visco – a very commonly used type of fuse that burns steadily.
Waterfall – a large row of upside down fountains that, when lit, resemble a waterfall
Wheel – also known as a saxon, it spins around in circles while attached to a wall and releases some kinds of effects.
Whistle – a whistling noise produced by the pyrotechnic composition: whistle mix
Whistle Mix - a composition that gives off a whistling noise when compressed