Pyro Stuff
CHOOSING THE FIREWORKS
This is only a basic summary of selecting fireworks for a firework display and what the Bonfire Societies use . . 
ROCKETS
One of the most popular fireworks, but only used in small numbers for public displays. A rocket motor propels the head to a height of anything up to 1000ft from where the head will burst into coloured stars or bangs. The rocket flight is normally stabilised by a wooden stick which, together with the motor casing falls to the ground afterwards.
This 'fallout' can be a hazard to spectators, greenhouses and other vulnerable objects, a characteristic which along with an unpredictable flight pattern in anything above a light breeze and their relative expense make them a less popular firework choice for display operators.
SHELLS
THE WORLDS LARGEST SINGLE FIREWORK WAS SET OFF AT A FESTIVAL IN JAPAN IN 1988. THE SHELL WEIGHED OVER HALF A TON AND THE BURST WAS OVER A KILOMETER ACROSS
These are the most common single fireworks seen at large bonfire society displays. A shell can be either spherical or cylindrical in shape, consisting of a central 'burst' charge of gunpowder surrounded by coloured stars or other effect units.
At least one delay fuse leads from the burst charge to the bottom of the shell, to which is fixed another charge, known as a 'lift'. A fast fuse (quickmatch 'leader') is attached to the lift for lighting. A lot of the shells are are hand made in house with Fletching having one of the loudest ever in the UK ( probably )
Shells come in sizes ranging from 2" to over 16" and are fired from tubes known as 'mortars' which are about 12-60" in length. The lift charge will propel the shell to several hundred feet (about 100' for every inch of diameter), and will take about 1 second per 100ft to reach its height.
During the ascent, the delay fuse will burn to the centre of the shell, igniting the burst at the top of the trajectory, and the fire is transferred to the coloured stars which are thrown out across the sky.
Because there have been a number of accidents involving shells (a shell in a mortar tube is effectively a huge gun), these fireworks are no longer sold to the general public and are only available to 'professional' display operators.
The mortar tube is often made of cardboard; in the event of a shell bursting in the tube the debris will only be flying paper. A good alternative which is more weatherproof is HDPE which is used for high pressure gas and water pipes. The mortar tubes are assembled into wooden racks which are then staked firmly to the ground.
SALUTES AND MAROONS
Instead of a shell with coloured stars, a salute or maroon is a single loud bang, often used to signal the end of a display.
MINES
A mine is similar to shells in that they are also fired from tubes. They do not have a burst charge, so the lift shoots stars upwards out of the tube usually in a tail bright shower.
ROMAN CANDLES
Made in a long cardboard tube, a roman candle may have several effects, which fire one after the other with a short delay in between.
Similar bore candles (14mm) have up to 10 'shots' of coloured stars (pearl, dragon), loud bangs/flash (flashing thunder), whistles, coloured bombettes (violet ball, peacock) while larger candles (up to 40mm) may have more elaborate effects such as silver coconut bombettes and crossettes (single coloured star splitting into 4 stars) A roman candle is rarely used singularly, so frames are made for 'v', trident and fan formations.
CAKES
Cakes are one of the most useful and varied of fireworks, a cake, is a box full of tubes each with a single effect. One fuse runs around all the tubes in the cake to set them off in sequence, making set up and lighting a display, much simpler than with individual fireworks.
GERBS AND FOUNTAINS
Gerbs and fountains emit a shower of sparks through a clay nozzle, either shooting high in the air or creating a force sufficient to turn a catherine wheel or other moving part. A cone is a type of fountain, which starts off gently and burns more vigorously towards the end as the burning surface area increases, as a firework a gerb or fountain is a usefull tool.
LANCES
Looking like a cigarette, a lance burns for about a minute with a strong coloured flame at one end. By fixing lances to letters, numbers or pictures, and viewing from end-on, they look like bright coloured dots and are used for making banners, badges, logos etc, " lance work "
WATERFALLS
A waterfall is made from several card or paper tubes hung vertically from a rope or wire. Burning for over a minute, bright white flakes fall gently and quietly from the tubes, looking like falling snow or a waterfall.
FLAMEBALLS AND FLAMEBURSTS
A flame ball / flame burst can either be aerial or on the ground, a lift charge is used with a slow burning fuse to ignite a black powder mixture which in turns ignites the petrol/diesel mixture ( similar to a shell ) or in the case of a ground effect just black powder via an electric match, the trick is to use the right combination and amount of the powder mix. These are handmade in house so to speak and cannot usually be purchased.
CHINESE CELEBRATION CRACKERS
My own personal favorite !, the chinese cracker and they come in all sort of sizes and reports from a 6" cake and upwards the biggest I have seen was about 6ft in diameter. They are used usually towards the end of a display or in my case on the mean streets of wherever I am bonfiring , I Lurve em !
FUSES
One of the most important lessons to learn about fireworks is that fuses come in two basic types - fast and slow fuse. It is very important to tell the difference, as lighting a fast fuse by hand could put the firer in a dangerous position.
Under normal circumstances most fireworks are quite safe to a firer standing very close when they are lit, but the instructions always say 'retire to a safe distance' because there is always a possibility of failure where the fireworks may be blown apart on the ground.
The most common type of fast fuse is 'quick match' which is made from string dipped in black powder (gunpowder) and wrapped inside a loosely fitting paper tube. Fire will travel through quick match at about 50 feet/sec. The best slow fuse to use is 'plastic igniter card', or PIC, made by ICI, and burns at a precise rate of 1 inch/sec. This means that a firework with a PIC fuse 6 inches long will give you at least 6 seconds to get away before it goes off.
The different types of fuses are used to join several fireworks together, for instance a fan of roman candles would be joined together with quickmatch, with a single tail of PIC as a slow fuse for lighting.
REMEMBER FIREWORKS ARE NOT TOYS TREAT THEM WITH RESPECT
