Fireworks Products And Effects (II)

                               Flying pigeon

The line rocket or flying pigeon is a very popular item at firework displays and frequently consists of a wooden block with a hole through the center so that it can slide along a tightly stretched rope or wire. Four 16mm rockets are fixed to the block and,in addition,there are four fierce drivers attached to a small hoop fixed on the block.

Smaller pigeon type fireworks,called rats,consist of very fierce drivers which follow each other down the wire.They are charged with a mixture of gunpowder and iron and the tubes are about 12mm in diameter.

                          Shells

The greatest skill of firework maker can be exhibited in the manufacture of star shells,or “bombs”as they frequently called. Shells are produced in huge quantities every year but the quality varies from,at one extreme,the most ordinary types,which literally drop the stars into the sky in a disorderly heap, to the magnificent pattern shells at the other extreme.

The shell maker thus has the choice of three methods of bursting round shells:

  1. Employ a small gunpowder charge and a weak exterior wall to obtain the bouquet effect.
  2. Employ a much fiercer bursting charge and a comparatively weak shell wall in order to obtain an even burst. The use of a fierce bursting charge involves the risk of destroying the stars or causing ignition failures.Flash powder is sometimes used for this purpose but there are many drawbacks and dangers to the technique.
  3. Employ a very strong outside shell wall and use a comparatively slow expanding bursting charge.

Round shells are used in various sizes.The smallest being made to fit a 50mm diameter tube and the largest 100mm.the most common sizes are 75mm,100mm,125mm,150mm and 200mm,these being fairly universal. 300mm and 400mm shells are sometimes manufactured but it is a byword among firework makers that their effect is frequently no better than a 150mm or 200mm shell.

In recent years plastic ball shells have become very common,the molded plastic being made in such a way that the delay and lifting charge are all built into the same unit.They are cheaper and easier to fill,though in some respects paper seems to be superior.

After the shell has been filled with stars and blowing,the fuse is carefully glued into place,but care must be taken to see that the fuse is secure or else it may be forced through into the shell by the lifting charge.

                     Gerbs

The French word”grebe”,meaning a spray or corn,is still used for firework fountains,particularly for those which produce force in choked tubes.A wide variety of fountains can be found within the firework range but generally speaking there are two basic types;those of the long narrow variety and the short squat fountains.The mixtures naturally vary immensely with the type of tube and method of filling.

                       Fountains

Tubes for fountains are usually about 25cm long and from 12-25mm in diameter.There are also other sizes which are smaller or larger than the ones mentioned.The wall thickness is sufficient to prevent the fire bursting the side of the tube.

The old English”flower pot”is produced from a combination of red orpiment and lampblack.

Silver fountains are made with titanium or aluminum.Titanium is uncomplicated,but aluminum powder varies tremendously from one manufacturer to another.

Glitter and flitter garbs are modifications of the corresponding star mixes. Yellow glitter is made with sodium oxalate and white glitter is made barium carbonate or strontium oxalate.

                  Rains

Gold and silver rains consist of long narrow fountains of small bore which are fierce enough to produce a good show of sparks.The tubes are about 6mm to 9mm in diameter and from 7.5cm to 12.5cm long.As they are cheap items they are invariably dry rolled,being merely pasted at the edge of the paper. Tubs are charged with a funnel and wire or other means,but is should be pointed out that dry compositions containing more than a few percent of aluminum should not be used in a funnel and wire apparatus.

                  Flying squibs

In effect these were fierce little drivers,but they are no longer sold to the public because of their erratic and consequently dangerous behavior.Tough little tubes about 9mm diameter with a”pulled in”choke were firmly charged with a fierce driver composition of gun powder and charcoal.When ignited,they scurried along the ground and could be both amusing and irritating.

                   Cones

Cones have been included chapter because they are really fountains,though they are not usually charged very solidly.

Some cones are fitted with a washer inside the cone itself to give a secondary effect,but this is not common.

                        Chip Gerbs

Fountains and cones have always been made with micro stars which were made from either small pieces of colored star composition or silver granules’. These were mixed with a gold charcoal mix and,needless to say,stars made with chlorate were hazardous.There was also a second problem in that the stars often burnt out inside the tube before they reached the outside.

The nature of these micro stars is such that light after a short delay and this gives them time to get out of the tube. However, the compositions need to be lightly charged to avoid breaking the stars and to get fast clean burning.

                    Pinwheels

There are several ways of making pinwheels,but good ones are not easy to manufacture.

Silver wheels can be made with gunpowder mixed with about 12% of bright aluminum powder.If the aluminum is too fast burning, explosion is likely,but if the aluminum is too slow,the wheel will not turn.These wheels are a problem,but the Germans make good ones.

                   Crackers

English crackers are made in exactly the same way as pinwheels in that the grain gunpowder is poured over a bundle of pipes and then shaken down.The pipes are made of brow Kraft paper,dry rolled.Manufacturers vary in their tastes as to which type of grain to employ.

When the pipes full of grain they are rolled several times between heavy rollers so that the grain is crushed and the pipes ate flattened.

A rather cheap and less successful method of making crackers is to enclose a length of thick,good quality match in close fitting length of match pipe,and complete it in the usual way.

              Torpedoes,throw down crackers and amerces

These specialist items are outside the normal range of firework manufacture,for they employ impact sensitive materials which are very dangerous to handle.

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