PYRO3.TXT Stars, Flares, and Color Mixtures This is part of a series of files on pyrotechnics and explosives. It's serious stuff, and can be really dangerous if you don't treat it seriously. For you kids out there who watch too many cartoons, remember that if a part of your body gets blown away in the REAL world, it STAYS blown away. If you can't treat this stuff with respect, don't screw around with it. Each file will start with a set of safety rules. Don't skip over them. Read 'em and MEMORIZE 'em!! At the beginning, there will be a set of general rules that always apply. Then there will be some things that you HAVE TO KNOW about the materials you will be using and making this time. Read it thoroughly before starting anything. Pyrotechnic preparations and explosives are, by their very nature, unstable, and subject to ignition by explosion or heat, shock, or friction. A clear understanding of their dangerous properties and due care in the handling of ingredients or finished products is necessary if accidents are to be avoided. Always observe all possible precautions, particularly the following: We will be using the following materials this time. Get familiar with them. Some can be highly dangerous. Aluminum Dust (and powder) Al An element used for brilliancy in the fine powder form. It can be purchased as a fine silvery or gray powder. All grades from technical to superpure (99.9%) can be used. It is dangerous to inhale the dust. The dust is also flammable, by itself. In coarser forms, like powder, it is less dangerous. Antimony Sulfide Sb S 2 3 Also known as "Black" Antimony Sulfide. (There is also a "Red" form, which is useless to us.) This is used to sharpen the report of firecrackers, salutes, etc, or to add color to a fire. The technical, black, powder is suitable. Avoid contact with the skin. Dermatitis or worse will be the result. Barium Chlorate Ba(ClO ) * H O 3 2 2 Available as a white powder. It is poisonous, as are all Barium salts. It is used both as an oxidizer and color imparter. It is as powerful as Potassium Chlorate and should be handled with the same care. Melting point is 414 degrees. Barium Nitrate Ba(NO ) 3 2 Poisonous. Used as an oxidizer and colorizer. The uses and precautions are the same as with a mixture containing Potassium Nitrate. Charcoal C A form of the element carbon. Used in fireworks and explosives as a reducing agent. It can be purchased as a dust on up to a coarse powder. Use dust form, unless otherwise specified. The softwood variety is best, and it should be black, not brown. Copper Acetoarsenite (CuO) As O Cu(C H O ) 3 2 3 2 3 2 2 The popular name for this is Paris Green. It is also called King's Green or Vienna Green. It has been used as an insecticide, and is available as a technical grade, poisonous, emerald green powder. It is used in fireworks to add color. Careful with this stuff. It contains arsenic. Copper Chloride CuCl 2 A color imparter. As with all copper salts, this is poisonous. Copper Sulfate CuSO *5H O 4 2 Known as Blue Vitriol, this poisonous compound is available as blue crystals or blue powder. Can be purchased in some drugstores and some agricultural supply stores. Used as a colorizer. Dextrine This can be purchased as a white or yellow powder. It is a good cheap glue for binding cases and stars in fireworks. Lampblack C This is another form of the element carbon. It is a very finely powdered black dust (soot, actually) resulting from the burning of crude oils. It is used for special effects in fireworks. Lead Chloride PbCl 3 Available as a white, crystalline, poisonous powder, which melts at 501 degrees. As with all lead salts, it is not only poisonous, but the poison accumulates in the body, so a lot of small, otherwise harmless doses can be as bad as one large dose. Mercurous Chloride HgCl Also known as calomel or Mercury Monochloride. This powder will brighten an otherwise dull colored mixture. Sometimes it is replaced by Hexachlorobenzene for the same purpose. This is non poisonous ONLY if it is 100% pure. Never confuse this chemical with Mercuric Chloride, which is poisonous in any purity. Potassium Chlorate KClO 3 This, perhaps, is the most widely used chemical in fireworks. Before it was known, mixtures were never spectacular in performance. It opened the door to what fireworks are today. It is a poisonous, white powder that is used as an oxidizer. Never ram or strike a mixture containing Potassium Chlorate. Do not store mixtures containing this chemical for any length of time, as they may explode spontaneously. Potassium Dichromate K Cr O 2 2 7 Also known as Potassium Bichromate. The commercial grade is used in fireworks and matches. The bright orange crystals are poisonous. Potassium Nitrate KNO 3 Commonly called Saltpeter. This chemical is an oxidizer which decomposes at 400 degrees. It is well known as a component of gunpowder and is also used in other firework pieces. Available as a white powder. Potassium Perchlorate KClO 4 Much more stable than its chlorate brother, this chemical is a white or slightly pink powder. It can often substitute for Potassium Chlorate to make the mixture safer. It will not yield its oxygen as easily, but to make up for this, it gives off more oxygen. It is also poisonous. Red Gum Rosin similar to shellac and can often replace it in many fireworks formulas. Red Gum is obtained from barks of trees. Shellac Powder An organic rosin made from the secretions of insects which live in India. The exact effect it produces in fireworks is not obtainable from other gums. The common mixture of shellac and alcohol sold in hardware stores should be avoided. Purchase the powdered variety, which is orange in color. Sodium Oxalate Na C O 2 2 4 Used in making yellow fires. Available as a fine dust, which you should avoid breathing. Strontium Carbonate SrCO 3 Known in the natural state as Strontianite, this chemical is used for adding a red color to fires. It comes as a white powder, in a pure, technical, or natural state. Strontium Nitrate Sr(NO ) 3 2 By far the most common chemical used to produce red in flares, stars and fires. Available in the technical grade as a white powder. It does double duty as an oxidizer, but has a disadvantage in that it will absorb some water from the air. Strontium Sulfate SrSO 4 Since this chemical does not absorb water as readily as the nitrate, it is often used when the powder is to be stored. In its natural state it is known as Celestine, which is comparable to the technical grade used in fireworks. Sulfur S A yellow element that acts as a reducing agent. It burns at 250 degrees, giving off choking fumes. Purchase the yellow, finely powdered form only. Other forms are useless without a lot of extra and otherwise unnecessary effort to powder it. Zinc Dust Zn Of all the forms of zinc available, only the dust form is in any way suitable. As a dust, it has the fineness of flour. Should be either of the technical or high purity grade. Avoid breathing the dust, which can cause lung damage. Used in certain star mixtures, and with sulfur, as a rocket fuel. The Chemistry of Pyrotechnics Most pyrotechnic mixtures follow a very simple set of chemical rules. We'll go over those now. Most mixtures contain an oxidizing agent, which usually produces oxygen used to burn the mixture, and a reducing agent, which burns to produce hot gasses. In addition, there can be coloring agents to impart a color to the fire, binders, which hold the mixture in a solid lump, and regulators that speed up or slow down the speed at which the mixture burns. These are not all the possibilities, but they cover most all cases. Oxidizing agents, such as nitrates, chlorates, and perchlorates provide the oxygen. They usually consist of a metal ion and the actual oxidizing radical. For example, Potassium Nitrate contains a metal ion (Potassium) and the oxidizing radical (the Nitrate). Instead of potassium, we could instead substitute other metals, like sodium, barium, or strontium, and the chemical would still supply oxygen to the burning mixture. But some are less desirable. Sodium Nitrate, for example, will absorb moisture out of the air, and this will make it harder to control the speed at which the mixture will burn. In the following examples, we'll use the letter "X" to show the presence of a generic metal ion. Note that Nitrates are stingy with the oxygen that they give up. They only give one third of what they have. Some Some Nitrate Nitrite Oxygen 2XNO ---> 2XN0 + O 3 2 2 Chlorates are very generous, on the other hand. They give up all the oxygen they have. Furthermore, they give it up more easily. It takes less heat, or less shock to get that oxygen loose. Mixtures using chlorates burn more spectacularly, because a smaller volume of the mix needs to be wasted on the oxidizer, and the ease with which the oxygen is supplied makes it burn faster. But the mixture is also MUCH more sensitive to shock. Some Some Chlorate Chloride Oxygen 2XClO ---> 2XCl + 3O 3 2 Perchlorates round out our usual set of oxidizing tools. Perchlorates contain even more oxygen than Chlorates, and also give it all up. However, they are not as sensitive as the Chlorates, so they make mixtures that are "safer". That is, they're less likely to explode if you drop or strike them. Some Some Perchlorate Chloride Oxygen XClO ---> XCl + 2O 4 2 Reducing agents, like sulfur and charcoal (carbon) simply burn the oxygen to produce sulfur dioxide and carbon dioxide. It's usually best to include a mixture of the two in a pyrotechnic mixture, as they burn at different speeds and temperatures, and the proper combination will help control the speed of combustion. Also, when extra fast burning speed is needed, like in rockets and firecrackers, metal powder is often added. The finer the powder, the faster the burning rate. The proportions change the speed, as well. Magnesium powder or dust is often used for speed. Aluminum du