Fireworks Products And Effects (I)

                         Colored Flames

Colored flames are made with almost the same compositions as those used for stars, except fuels which are used to make stars burn rapidly (   charcoal for example) are usually omitted. On the contrary it is usual in these items to add materials which will retard the burning rate. Colored fires. Torches and Bengal illuminations which are sold to the public are usually required to burn quite slowly. And normally have the burning rate reduced by adjusting the fuel. The use of coarsely ground materials, or the cutting down or increasing of the amount of fuel can have this effect, but it is also usual to add retardants such as sawdust, wood flour, starch or flour. The addition of these materials also makes the composition cheaper, of course, but care must be taken with materials such as wood meal since they can contain a good deal of water.

                   Bengal illuminations

This special type of flare candle is used for illuminating public buildings and is extensively used in Europe for castles which particularly lend themselves to this type of illumination. In order to fulfill the necessary conditions, the composition should produce maximum color, burn efficiently but as slowly  as  possible, (i.e.40 to 60 seconds per 25mm), and not emit too much smoke.

The candles are made in various sizes, but the large ones are about 60mm in diameter 30cm long and have a wall thickness of about 1.5mm. the end of the candle is fitted with a wooden plug and a screw eye for attachment to the holder. The candle is fixed so that it burns in a horizontal position, so that the dross will not run down the side of the thin wad accelerate the burning time. Lastly, the candle is placed behind some kind of shield so that the onlookers do not see it burning.

                   Lances

Large quantities of these items are manufactured every year for use in making set pieces, as fire pictures, mottos, all made with these little tubes of colored fire. Lances are usually 8mm or 10mm in diameter and about 10cm long. The paper is usually an 0.004 bond or poster paper cut up into pieces 95mmX125mm,and they are dry-tolled on a former which is countersunk at one end.

A funnel and wire are used to charge the composition, but the base of the funnel has a nozzle which goes about 10mm into the lance tube. In this way, the lances can be filled to within 10mm of the top. The nest operation is to add topping composition in a similar way, to a depth of 8mm.

                          Port fires

Port fires, which are used for lighting fireworks are exactly the same way as lances, except that the tube is usually longer and has a  slightly thicker tube. Port fires are normally 9mm inside diameter and a bout 38cm long. The paper for the 38cm size would be 18cm X 38cm. port fires usually burn three or four minutes, but they must not burn too slowly or they are apt to go out.

                          Waterfalls

The general principle of formulation is to ensure that there is an excess of aluminum present. In order that the burning material will fall to the ground with the appropriate sparks. The tube is usually a wet rolled tube consisting of four or five a  0.010 Kraft paper on a 18mm-24mm former. The tube 15 to 30cm naturally must burn away with the composition or else the essential dross will not fall to the ground.

                     Roman Candles

There can be no doubt that it requires much practice to make really good roman candles, and the best ones are still made by hand. So many factors play a part in the performance of the candle with the inevitable result that there is always something to go wrong.

The best tubes are hand rolled and it is quite essential that the inside lap of paper is completely stuck down or else the powder will creep down the loose paper, cause a “blow-through” and eject stars like machine-gun bullets.

The quality of the paper of the tube is also quite important. A good quality Kraft paper, for example, rolled with good casein glue, provides a tough tube which hardly burns a way during the firing of the candle.

The fuse ideally should produce a good show of golden sparks, but this is not necessary, of course, and there is always a tendency to produce too much smoke as would be expected.

                      Comets

 Comets are single roman candle stars in their simplest form, but they are usually gunpowder type compositions since they are ejected at great speeds. The smaller comets of about 24mm in diameter can be adequately charged with a mallet, but the larger comets should be pressed in order to get greater consistency.

Effective comet bombs can be made by pressing a star in the bottom of a paper tube and then filling the remainder of the tube with stars or other effects. The result is a spiral of fire terminating in a star burst.

                              Mines

The ordinary mines are simply a charge of gunpowder and stars at the base of a strong tube which acts as a gun.

                    Flash and sound

Explosive fireworks more than anything else have been the cause of serious accidents and they have probably done more damage to the firework in dusty than anything else! Flash crackers in their various forms were on sale to the public for far too long and happily have been forbidden in many European countries.

Flash compositions of some types will cause explosions in the lightest of containers-even sometimes in just a few turns of paper-but it also happens that these compositions are extremely breast and sensitive. Horrifying mixtures of potassium chlorate, pyre aluminum, sculpture and barium nitrate have been employed and should be avoided at all costs.

These mixtures in themselves were very sensitive to impact and friction and a quantity of less than 1 gm could be quite devastating.

                   Whistles

The oldest whistles were made with potassium pirate. Pirate whistles are very shrill and can be very entertaining in roman candles with their black tails.

Picric whistles are not popular with the firework mainly because no one cares to work with them. The salt stains the fingers and clothing a bright yellow, and the taste is bitter and unpleasant.

It is well known that picric acid and its salts are sensitive to impact and great care needs to be taken when charging potassium pirate.

                   Humming fireworks

Humming fireworks are constructed in a manner which will allow a jet of issue out of a tube at such a speed and at such an angle that the tube will be caused to rotate on its own axis. In the air this causes a humming noise.

The best hummers are made with a long steady stream of gas.

                     Rockets

Rockets are one of the oldest pyrotechnic devices. All rockets, the smallest firework to the giant satellite carrying Saturn, have four basic components in common. They are:

A case or rocket motor;

A “choke” or Ventura;

A propellant charge;

A flight stabilizing device.

Rockets are reaction motors. On ignition, the propellant charge produces gas a high temperature and so internal pressure of the gases in the rocket body is raised. Rocket bodies or cases may be made from a variety of materials.

The “choke” or venture is an important part of the rocket. In firework rockets the “choke” is quite crude and is often formed by constricting case whilst it is damp.

The traditional propellant charge for firework rocket is either:

Gunpowder;

A mixture of mea led gunpowder and charcoal; 

A simple mixture of potassium nitrate, sculpture and charcoal;

A mixture of mea led gunpowder and calcium carbonate.

Charcoal is the most difficult ingredient to control.

Stabilization of firework rockets is achieved by means of a stick.

                       Drivers

Wheels and moving fireworks are operated by rockets or more commonly by drivers. Drivers are stout tubes from 12mm to 40mm internal diameter, choked down to about 1/3 of a diameter and charged with a fierce composition containing a high percentage of gunpowder.

Small wheels are turned quite adequately with tubes which are 12mm or 16mm in diameter and a bout 100mm long.

The smaller drivers are used for a variety of different types wheels.

Large drivers are used for the bigger display wheels from 2-5 meters in diameter.

                      Saxons

These fireworks are used in combination with a small color case to produce small colored wheels which are usually part of a larger design.

Thick walled tubes are charged with composition, but the tube is closed with clay at both ends, and the fire issues from a hole which is cut into the side of the tube at right angles to the axis of the tube.

                      Tourbillions

The French word “tourbillion” or “whirl wind” is still used to describe these fireworks which have appeared in many forms and sizes. The older and larger forms were in effect a fierce type of Saxon which first of all spun around on the ground and then lifted up into the air by means of two or four boles bored in the underside.

The larger sizes are made with a tube which is approximately 24mm. diameter, 20cm. long and with thickness of 6mm.

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