Firework stars

IV. Ammonium perchlornte, Nlli,C10, TO Blue fireworks star (with U... 

Stationary and moving pellets of composition (fireworks stars, flares, tracers, etc.)... 

Most glitter effects are seen as fireworks stars or comets. The drossy residues produced by burning glitter compositions makes fountain effects difficult, but not impossible to produce. 

Blue fireworks star Reference (with charcod tail)... 

Flares, Signaling Devices, and other Pyrotechnics. A large number of formulations contg K perchlorate have been reported. Some devices which use these are red RR signal flares (Refs 2 22, p 275) parachute flares (Ref 6) stars for use in signaling pistols (Very pistols) (Refs 5. 22, p 275) variously colored flares (Refs 19, pp 197-8 22, p 275) stars and other components of display fireworks (Refs 16 32) ... 

Figure 3.7 Tumbling stars for Wells rockets ca. 1968. (Courtesy of Pains Fireworks Ltd.)...

Having outlined the form and function of two typical star shells we can now attempt to quantify some of the ballistic effects that give rise to the performance of these spectacular fireworks. 

The fireworks that operators refer to as candles or Romans originated in Rome at the time of the Renaissance in the 14th century. Every person in the audience is familiar with these fireworks that eject a succession of stars, mini-shells and hummers into the sky, the projectiles reaching greater heights with every shot while the fireworks send great columns of sparks skywards between those shots. 

The difficulty in producing a good blue flame stems from several important considerations. Firstly, impurities in the chemicals present in the firework tend to produce yellow flames, which detract from the blue secondly, coloured flames follow similar physico-chemical phenomena but operate in different regions of the spectrum. Consequently the copper salts (that are normally utihsed for the production of blue stars) decompose thermally to produce a variety of emissions that radiate from about 325 to 660 nm i.e. from green, blue and violet to orange-red) simultaneously polluting the pure blue flame which appears in the 400 to 455 nm region. 

The most favoured knot when tying posts to stakes is the clove hitch. With practice, this knot is quickly effected and easy to undo. However, when tying candles, care should be taken so that the knot is not over-tightened, otherwise crushing of the firework tube might occur which could interfere with the ejection of the stars. 

COMET A single large star expelled from a firework such as a mine. 

FOUNTAIN A long, tubular firework from which a jet or spray of sparks issues, sometimes accompanied by stars. 

Loading An operator, working with the minimum quantity of bulk powder, loads the composition into tubes or other containers, or produces pellets for later use in finished items. The making of "stars" - small pieces of color-producing composition used in aerial fireworks - is an example of this pelleting operation. 

To achieve rapid burning - such as in the brightly-colored "stars" used in aerial fireworks and Very pistol cartridges -compositions will contain charcoal or a metallic fuel (usually magnesium). Fine particle sizes will be used, and ah ingredients will be well-mixed to achieve a very homogeneous - and fast burning mixture. 

Figure 22. Seventeenth-Century Fireworks Display, Lorrain, 1630. Flaming swords, shields and pikes, wheel of fire, rockets, stars, candles, serpents, water fireworks. The sun and the moon which are pictured are presumably aerial bombs, and the dragons are probably dragon rockets running on ropes but may possibly be imaginative representations of serpents of fire. The picture is convincing evidence that many of the varieties of fireworks which are now used (in improved form) for display purposes were already in use three centuries ago.

True blue fireworks are the hardest to make, since the compound copper chloride breaks down in a hot flame. In recent years, fireworks experts have used magnalium—a mixture of the alkaline earth metal magnesium and aluminum—to boost all firework colors. Magnalium has made the blues brighter, but pyrotechnicians are still searching for a blue as brilliant as the red and green and yellow stars that light up a Fourth of July sky. 

Homan Candle Scoops.—No species of fireworks require greater care in their construction than Homan candles. In the first place the stars must be fierce, that they may light thoroughly next, they must not be driven out with toogreat velocity. For this purpose the blowing powder must be carefully adjusted. The stars also must be qf so easy a fit that when put Into the case they may fall to the proper depth of their own accord. If they require pushing, they are too tight, and will probably bo blown out blind. When made as directed they will necessarily be of an easy fit, as they will be of the inner diameter of the brass tube, while the bore of the case is equal to its external diameter,... 

Gunpowder for fireworks is used in two forms, meal powder and grain powder. Meal powder is a fine black dust and is employed In all cases of mixing. Grain powder is of three kinds, F, FF, and FFF—fine, double fine and treble fine. FFF is best for crackers, simply tiecause it runs rapidly down the pipes for driving stars, shells, etc, F will be sufficient... 

Colored Fires for Stars.2067 Japanese Firework Mixtures.2127 Red Bengal Lights.2072... 

Firework Mixture, Japanese.2127 Matches, Congreve.2146 Roman Candles, Stars for. ... 2058, 206s... 

A typical aerial shell used in fireworks displays. Time-delayed fuses cause a shell to explode in stages. In this case a red star-burst occurs first followed by a blue starbursb and finally a flash and loud report. Reprinted with permission from Chemical Engineering News, Vol. 59, Issue 26, June 29,1981, p. 25. Copyright 1981 American Chemical Society. 

Tessier introduced the use of cryolite (AlNaaF ) for the yellow coloring of stars, lances, and Bengal lights. In his second edition he includes a chapter on the small pyrotechnic pieces which are knonm as Japanese fireworks, giving formulas for them, and another on the picrates, which he studied extensively. The picrates of sodium, potassium, and ammonium crystallize in the anhydrous condition. Those of barium, strontium, calcium, magnesium, zinc, iron, and copper are hygroscopic and contain considerable water of crystallization which makes them unfit for use in pyrotechnic compositions. Lead picrate, with 1 H3O, detonates... 

FiouBfi 2S. A Star Plate or Star Board in Use. (Courtesy National Fireworks Company.)... 

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