430 lines
18 KiB
Plaintext
430 lines
18 KiB
Plaintext
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Stars, Flares, and Color Mixtures
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We will be using the following materials this time. Get familiar with them.
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Some can be highly dangerous.
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Aluminum Dust (and powder) Al
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An element used for brilliancy in the fine powder form. It can be purchased as
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a fine silvery or gray powder. All grades from technical to superpure (99.9%)
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can be used. It is dangerous to inhale the dust. The dust is also flammable, by
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itself. In coarser forms, like powder, it is less dangerous.
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Antimony Sulfide Sb S
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2 3
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Also known as "Black" Antimony Sulfide. (There is also a "Red" form, which is
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useless to us.) This is used to sharpen the report of firecrackers, salutes,
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etc, or to add color to a fire. The technical, black, powder is suitable. Avoid
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contact with the skin. Dermatitis or worse will be the result.
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Barium Chlorate Ba(ClO ) * H O
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3 2 2
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Available as a white powder. It is poisonous, as are all Barium salts. It is
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used both as an oxidizer and color imparter. It is as powerful as Potassium
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Chlorate and should be handled with the same care. Melting point is 414
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degrees.
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Barium Nitrate Ba(NO )
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3 2
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Poisonous. Used as an oxidizer and colorizer. The uses and precautions are the
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same as with a mixture containing Potassium Nitrate.
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Charcoal C
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A form of the element carbon. Used in fireworks and explosives as a reducing
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agent. It can be purchased as a dust on up to a coarse powder. Use dust form,
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unless otherwise specified. The softwood variety is best, and it should be
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black, not brown.
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Copper Acetoarsenite (CuO) As O Cu(C H O )
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3 2 3 2 3 2 2
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The popular name for this is Paris Green. It is also called King's Green or
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Vienna Green. It has been used as an insecticide, and is available as a
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technical grade, poisonous, emerald green powder. It is used in fireworks to
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add color. Careful with this stuff. It contains arsenic.
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Copper Chloride CuCl
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2
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A color imparter. As with all copper salts, this is poisonous.
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Copper Sulfate CuSO *5H O
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4 2
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Known as Blue Vitriol, this poisonous compound is available as blue crystals or
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blue powder. Can be purchased in some drugstores and some agricultural supply
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stores. Used as a colorizer.
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Dextrine
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This can be purchased as a white or yellow powder. It is a good cheap glue for
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binding cases and stars in fireworks.
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Lampblack C
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This is another form of the element carbon. It is a very finely powdered black
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dust (soot, actually) resulting from the burning of crude oils. It is used for
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special effects in fireworks.
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Lead Chloride PbCl
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3
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Available as a white, crystalline, poisonous powder, which melts at 501
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degrees. As with all lead salts, it is not only poisonous, but the poison
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accumulates in the body, so a lot of small, otherwise harmless doses can be as
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bad as one large dose.
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Mercurous Chloride HgCl
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Also known as calomel or Mercury Monochloride. This powder will brighten an
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otherwise dull colored mixture. Sometimes it is replaced by Hexachlorobenzene
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for the same purpose. This is non poisonous ONLY if it is 100% pure. Never
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confuse this chemical with Mercuric Chloride, which is poisonous in any purity.
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Potassium Chlorate KClO
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3
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This, perhaps, is the most widely used chemical in fireworks. Before it was
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known, mixtures were never spectacular in performance. It opened the door to
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what fireworks are today. It is a poisonous, white powder that is used as an
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oxidizer. Never ram or strike a mixture containing Potassium Chlorate. Do not
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store mixtures containing this chemical for any length of time, as they may
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explode spontaneously.
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Potassium Dichromate K Cr O
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2 2 7
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Also known as Potassium Bichromate. The commercial grade is used in fireworks
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and matches. The bright orange crystals are poisonous.
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Potassium Nitrate KNO
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3
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Commonly called Saltpeter. This chemical is an oxidizer which decomposes at 400
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degrees. It is well known as a component of gunpowder and is also used in other
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firework pieces. Available as a white powder.
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Potassium Perchlorate KClO
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4
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Much more stable than its chlorate brother, this chemical is a white or
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slightly pink powder. It can often substitute for Potassium Chlorate to make
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the mixture safer. It will not yield its oxygen as easily, but to make up for
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this, it gives off more oxygen. It is also poisonous.
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Red Gum
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Rosin similar to shellac and can often replace it in many fireworks formulas.
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Red Gum is obtained from barks of trees.
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Shellac Powder
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An organic rosin made from the secretions of insects which live in India. The
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exact effect it produces in fireworks is not obtainable from other gums. The
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common mixture of shellac and alcohol sold in hardware stores should be
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avoided. Purchase the powdered variety, which is orange in color.
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Sodium Oxalate Na C O
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2 2 4
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Used in making yellow fires. Available as a fine dust, which you should avoid
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breathing.
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Strontium Carbonate SrCO
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3
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Known in the natural state as Strontianite, this chemical is used for adding a
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red color to fires. It comes as a white powder, in a pure, technical, or
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natural state.
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Strontium Nitrate Sr(NO )
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3 2
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By far the most common chemical used to produce red in flares, stars and fires.
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Available in the technical grade as a white powder. It does double duty as an
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oxidizer, but has a disadvantage in that it will absorb some water from the
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air.
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Strontium Sulfate SrSO
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4
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Since this chemical does not absorb water as readily as the nitrate, it is
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often used when the powder is to be stored. In its natural state it is known as
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Celestine, which is comparable to the technical grade used in fireworks.
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Sulfur S
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A yellow element that acts as a reducing agent. It burns at 250 degrees, giving
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off choking fumes. Purchase the yellow, finely powdered form only. Other forms
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are useless without a lot of extra and otherwise unnecessary effort to powder
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it.
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Zinc Dust Zn
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Of all the forms of zinc available, only the dust form is in any way suitable.
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As a dust, it has the fineness of flour. Should be either of the technical or
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high purity grade. Avoid breathing the dust, which can cause lung damage. Used
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in certain star mixtures, and with sulfur, as a rocket fuel.
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The Chemistry of Pyrotechnics
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Most pyrotechnic mixtures follow a very simple set of chemical rules. We'll go
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over those now. Most mixtures contain an oxidizing agent, which usually
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produces oxygen used to burn the mixture, and a reducing agent, which burns to
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produce hot gasses. In addition, there can be coloring agents to impart a color
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to the fire, binders, which hold the mixture in a solid lump, and regulators
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that speed up or slow down the speed at which the mixture burns. These are not
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all the possibilities, but they cover most all cases.
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Oxidizing agents, such as nitrates, chlorates, and perchlorates provide the
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oxygen. They usually consist of a metal ion and the actual oxidizing radical.
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For example, Potassium Nitrate contains a metal ion (Potassium) and the
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oxidizing radical (the Nitrate). Instead of potassium, we could instead
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substitute other metals, like sodium, barium, or strontium, and the chemical
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would still supply oxygen to the burning mixture. But some are less desirable.
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Sodium Nitrate, for example, will absorb moisture out of the air, and this will
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make it harder to control the speed at which the mixture will burn.
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In the following examples, we'll use the letter "X" to show the presence of a
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generic metal ion.
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Note that Nitrates are stingy with the oxygen that they give up. They only give
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one third of what they have.
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Some Some
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Nitrate Nitrite Oxygen
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2XNO ---> 2XN0 + O
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3 2 2
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Chlorates are very generous, on the other hand. They give up all the oxygen
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they have. Furthermore, they give it up more easily. It takes less heat, or
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less shock to get that oxygen loose. Mixtures using chlorates burn more
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spectacularly, because a smaller volume of the mix needs to be wasted on the
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oxidizer, and the ease with which the oxygen is supplied makes it burn faster.
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But the mixture is also MUCH more sensitive to shock.
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Some Some
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Chlorate Chloride Oxygen
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2XClO ---> 2XCl + 3O
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3 2
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Perchlorates round out our usual set of oxidizing tools. Perchlorates contain
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even more oxygen than Chlorates, and also give it all up. However, they are not
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as sensitive as the Chlorates, so they make mixtures that are "safer". That is,
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they're less likely to explode if you drop or strike them.
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Some Some
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Perchlorate Chloride Oxygen
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XClO ---> XCl + 2O
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4 2
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Reducing agents, like sulfur and charcoal (carbon) simply burn the oxygen to
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produce sulfur dioxide and carbon dioxide. It's usually best to include a
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mixture of the two in a pyrotechnic mixture, as they burn at different speeds
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and temperatures, and the proper combination will help control the speed of
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combustion. Also, when extra fast burning speed is needed, like in rockets and
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firecrackers, metal powder is often added. The finer the powder, the faster the
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burning rate. The proportions change the speed, as well. Magnesium powder or
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dust is often used for speed. Aluminum dust works, but not as well. Zinc dust
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is used in some cases. Powdered metal, (not dust) particularly aluminum or
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iron, are often used to produce a mixtire that shoots out sparks as it burns.
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In rare cases, it is desirable to slow down the burning speed. In this case,
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corn meal is often used. It burns, so acts as a reducing agent, but it doesn't
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burn very well.
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Coloring agents are very interesting. It's long been known that various metals
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produce different colored flames when burned in a fire. The reasons are buried
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in the realm of quantum physics, but the results are what matters, and we can
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present them here. Note that if we use an oxidizing agent that contains a
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colorizing metal, it can do a double job. It can produce oxygen and color.
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Barium -Barium salts give a pleasant green color. Barium Nitrate is most
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often used.
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Strontium -Strontium salts give a strong red color. Strontium Nitrate is a
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very convenient material for red.
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Sodium -Sodium salts give an intense yellow color. So intense in fact that
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any sodium compounds in a mixture will usually wash out other
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colorizers. As has been said, Sodium Nitrate absorbs moisture from
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the air, and so is not really suitable to impart color. Instead,
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Sodium Oxalate is usually used. This does not absorb lots of water,
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but has the disadvantage of being very poisonous.
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Copper -Copper salts are used to give a blue color. Blue is the most
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difficult color to produce, and it's usually not too spectacular.
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Usually Copper Acetoarsenite (Paris Green) is used. This compound
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contains arsenic, and is very poisonous. Since it still doesn't
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produce a very memorable blue, it's often used with mercurous
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chloride, which enhances the color, but is also poisonous, and
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expensive, to boot.
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Potassium -Potassium salts will give a delicate purple color, if they'e very
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pure. The cheaper lab grades of potassium nitrate often contain
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traces of sodium, which completely obscure the purple color. In
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order to get the purple coloring, very pure grades must be used,
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and you must be very careful to mix it in very clean vessels, and
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scoop it from the supply jar with a very clean scoop. The color is
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certainly worth the effort, if you can get it.
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Some mixtures that burn in colors also contain binders, that hold the mixture
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together in a solid lump. These lumps are usually referred to as stars. The
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balls fired from a roman candle or the colorful showers sprayed from aerial
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bombs are examples of stars. Depending on the mixture, the binder is either a
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starch called dextrine or finely powdered orange shellac. A shellac-like
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material called red gum is also used on occasion. In some mixtures, the shellac
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powder also helps produce a nice color. Shellac mixtures are moistened with
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alcohol to get them to stick together. Dextrine mixtures are moistened with
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water.
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If the colored mixture is to be used as a flare, it's just packed into a thin
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paper tube. If it's to be fired from a roman candle, it's usually extruded from
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a heavy tube by pushing it out with a dowel, and the pieces are cut off as the
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proper length pops out. Stars fired from an aerial bomb are usually made by
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rolling the moist mixture flat, and cutting it with a knife into small cubes.
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Stars that are extruded are often called "pumped stars" those that are rolled
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out are "cut stars".
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The following are formulas for mixtures that burn with various colors. Parts
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are by weight.
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Red
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Potassium Chlorate 9
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Lampblack 1
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Strontium Nitrate 9
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bind with shellac
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dissolved in alcohol
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Blue
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Potassium Chlorate 9 This one is inferior
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Copper Acetoarsenite 2 Potassium Chlorate 12
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Mercurous Chloride 1 Copper Sulfate 6
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Sulfur 2 Lead Chloride 1
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bind with dextrine Sulfur 4
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in water bind with dextrin in water
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Green
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Barium Chlorate 8 Barium Nitrate 3
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Lampblack 1 Potassium Chlorate 4
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Shellac Powder 1 Shellac Powder 1
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bind with alcohol Dextrine 1/4
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Bind with alcohol
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Yellow
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Potassium Chlorate 8 Potassium Chlorate 8
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Sodium Oxalate 3 Sodium Oxalate 4
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Lampblack 2 Shellac Powder 2
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Bind with shellac in Dextrine 1
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alcohol or dextrine Bind with alcohol
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in water
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White
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Potassium Nitrate 6
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Sulfur 1
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Antimony Sulfide 2
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bind with dextrine in
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water
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Orange
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Strontium Nitrate 36
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Sodium Oxalate 8
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Potassium Chlorate 5
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Shellac Powder 5
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Sulfur 3
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Bind with alcohol
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Purple (ingredients must be very pure)
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Potassium Chlorate 36 This one has more of a lilac color
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Strontium Sulfate 10 Potassium Chlorate 38
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Copper Sulfate 5 Strontium Carbonate 18
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Lead Chloride 2 Copper Chloride 4
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Charcoal 2 Lead Chloride 2
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Sulfur 12 Sulfur 14
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bind with dextrine in bind with dextrine in water
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water
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Brilliant White
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Potassium Perchlorate 12
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Aluminum Dust 4
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Dextrine 1
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Bind with water
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Golden Twinkler Stars - Falls through the air and burns in an on and off
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manner. The effect is spectacular. A pumped or cut star.
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Potassium Nitrate 18
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Sulfur 3
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Lampblack 3
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Aluminum Powder 3
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Antimony Sulfide 3
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Sodium Oxalate 4
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Dextrine 2
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Bind with water
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Zinc Spreader Stars - Shoot out pieces of burning zinc and charcoal. These
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stars are much heavier than usual, and require larger charges if they're to
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be fired from a tube.
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Zinc Dust 72
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Potassium Chlorate 15
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Potassium Dichromate 12
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Granular Charcoal 12
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Dextrine 2
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bind with water
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Electric Stars - Stars that contain aluminum powder
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Potassium Nitrate 15 Potassium Chlorate 60
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Aluminum, fine 2 Barium Nitrate 5
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Aluminum, medium 1 Aluminum, fine 9
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Black Powder 2 Aluminum, medium 4
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Antimony Sulfide 3 Aluminum, coarse 3
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Sulfur 4 Charcoal 2
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bind with dextrine in Dextrin 5
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water bind with red gum in
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water
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Potassium Perchlorate 6
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Barium Nitrate 1 Potassium Perchlorate 4
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Aluminum 20 Aluminum, medium 2
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Dextrin 1 Dextrin 1
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bind with shellac in bind with shellac in alcohol
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alcohol
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Simpler Zinc Spreaders
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Potassium Nitrate 14 Potassium Chlorate 5
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Zinc Dust 40 Potassium Dichromate 4
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Charcoal 7 Charcoal, medium 4
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Sulfur 4 Zinc Dust 24
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bind with dextrine in bind with dextrine in water
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water
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Willow Tree Stars - Use large amounts of lampblack -- too much to burn fully.
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Gives a willow tree effect.
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Potassium Chlorate 10
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Potassium Nitrate 5
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Sulfur 1
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Lampblack 18
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bind with dextrine in water
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In future files, we'll look at using these mixtures to produce roman candles,
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aerial bombs, and other effects. As always, don't forget that it's just plain
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stupid to go buying all these materials from one chemical supply house. When
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you buy it all as a group, they know what you plan to do with it, and they keep
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records. If anyone goes investigating the source of homemade fireworks and
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checks with your supplier, there will be a lead straight to you. Be sure to
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cover your tracks.
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