From: lyn@kitty.ksu.ksu.edu (Myself)
Newsgroups: rec.pyrotechnics
Subject: gopher files 3/4
Date: 16 Apr 1992 20:33:06 -0500
Organization: Kansas State University
Distribution: world
NNTP-Posting-Host: kitty.ksu.ksu.edu
Keywords: gopher


here is part 3 of 4

------------------------------ cut here ------------------------------------------                  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:           
                                                                               
         1. Mix only small batches at one time. This means a few grams, or at 
            most, an ounce or so. Don't go for big mixes -- they only make for 
            bigger accidents. The power of an explosive cubes itself with
            every ounce. (9 Ounces is 729 times as powerful as one ounce.)
                                                                              
         2. When weighing chemicals, use a clean piece of paper on the scale 
            pan for each item. Then discard the used paper into a bucket of 
            water before weighing the next ingredient.                         
                                                                               
         3. Be a safe worker. Dispose of any chemicals spilled on the 
            workbench or equipment between weighings. Don't keep open 
            containers of chemicals on your table, since accidental spillage 
            or mixing may occur. When finished with a container, close it, and 
            replace it on the storage shelf. Use only clean equipment.        
                                                                               
         4. Where chemicals are to be ground, grind them separately, NEVER 
            TOGETHER. Thoroughly wash and clean equipment before grinding 
            another ingredient.                                                
                                                                               
         5. Mixing of batches should be done outdoors, away from flammable 
            structures, such as buildings, barns, garages, etc. Mixes should 
            also be made in NON METALLIC containers to avoid sparks. Glass 
            also should not be used since it will shatter in case of an 
            accident. Handy small containers can be made by cutting off the 
            top of a plastic bottle three or four inches from the bottom. Some 
            mixes may most conveniently be made by placing the ingredients in 
            a plastic bottle and rolling around until the mixture is uniform. 
            In all cases, point the open end of the container away from 
            yourself. Never hold your body or face over the container. Any 
            stirring should be done with a wooden paddle or stick to avoid 
            sparks or static.                                                 
                                                                               
            Powdered or ground materials may also be mixed by placing them on 
            a large sheet of paper on a flat surface and then rolling them 
            across the sheet by lifting the sides and corners one at a time.  
                                                                               
         6. Never ram or tamp mixes into paper or cardboard tubes. Pour the 
            material in and gently tap or shake the tube to settle the 
            contents down.                                                    
                                                                               
         7. Store ingredients and finished mixes where they will not be a fire 
            hazard away from heat and flame. Finished preparations may be 
            stored in plastic bottles which will not shatter in case of an 
            accident. Since many of the ingredients and mixes are poisonous, 
            they should be stored out of reach of children or pets, preferably 
            locked away.                                                       
                                                                               
         8. Be sure threads of screw top containers and caps are thoroughly 
            cleaned. This applies also to containers with stoppers of rubber 
            or cork and to all other types of closures. Traces of mixture 
            caught between the container and closure may be ignited by the 
            friction of opening or closing the container. Throughout any 
            procedure, WORK WITH CLEAN CONDITIONS.                             
                                                                               
         9. ALWAYS WEAR A FACE SHIELD OR AT LEAST SHATTERPROOF SAFETY GLASSES. 
            Any careful worker does when handling dangerous materials. Be sure 
            lenses and frames are not flammable.                               
                                                                               
        10. Always wear a dust respirator when handling chemicals in dust 
            form. These small particles gather in your lungs and stay there. 
            They may cause serious illnesses later on in life.                
                                                                               
        11. Always wear gloves when working with chemicals.                    
                                                                               
        12. Always wear a waterproof lab apron.                                
                                                                               
        13. If you must work indoors, have a good ventilation system.          
                                                                               
        14. Never smoke anywhere near where you are working.                   
                                                                               
        15. Make sure there are NO open flames present, and NO MOTORS (they 
            produce sparks inside.) No hot water heaters, furnaces, or pilot 
            lights in stoves!! Sparks have been known to very readily explode 
            dust floating in the air.                                          
                                                                               
        16. ALWAYS work with someone. Two heads are better than one. 
                                                                               
        17. Have a source of water READILY available. (Fire extinguisher, 
            hose, etc.)                                                       
                                                                               
        18. Never, under any circumstances, use any metal to load chemicals or 
            put chemicals in. Fireworks with metal casings are worse to handle 
            than a live hand grenade. Never use any metal container or can. 
            This includes the very dangerous CO2 cartridges. Many people have 
            been KILLED because of flying fragments from metal casings. Again, 
            please do not use metal in any circumstance.                       
                                                                               
        19. Always be thoroughly familiar with the chemicals you are using. 
            Some information will be included in each file, but look for 
            whatever extra information you can. Materials that were once 
            thought to be safe can later be found out to be dangerous stuff.   
                                                                               
        20. Wash your hands and face thoroughly after using chemicals. Don't 
            forget to wash your EARS AND YOUR NOSE.                            
                                                                               
        21. If any device you've built fails to work, leave it alone. After a 
            half hour or so, you may try to bury it, but never try to unload 
            or reuse any dud.                                                 
                                                                               
        22. If dust particles start to form in the air, stop what you are 
            doing and leave until it settles.                                  
                                                                               
        23. Read the entire file before trying to do anything.                 
                                                                               
        24. NEVER strike any mixture containing Chlorates, Nitrates, 
            Perchlorates, Permanganates, Bichromates, or powdered metals don't 
            drop them, or even handle them roughly.                            
                                                                               
These rules may all look like a lot of silly nonsense, but let's look at one 
example. When the move "The Wizard of OZ" was made, the actress who played the 
good witch was severely burned when one of the exploding special effects got 
out of hand. The actress who played the bad witch got really messed up by the 
green coloring used on her face, and the original actor who played the Tin Man 
got his lungs destroyed by the aluminum dust used to color his face. The actor 
we know of as the tin man was actually a replacement. The point is, these 
chemicals were being used under the direction of people a lot more knowlegable 
of chemicals than you are, and terrible accidents still happened. Don't take 
this stuff lightly.                                                            

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 dust works, but not as well. Zinc dust 
is used in some cases. Powdered metal, (not dust) particularly aluminum or 
iron, are often used to produce a mixtire that shoots out sparks as it burns. 
In rare cases, it is desirable to slow down the burning speed. In this case, 
corn meal is often used. It burns, so acts as a reducing agent, but it doesn't 
burn very well.


Coloring agents are very interesting. It's long been known that various metals 
produce different colored flames when burned in a fire. The reasons are buried 
in the realm of quantum physics, but the results are what matters, and we can 
present them here. Note that if we use an oxidizing agent that contains a 
colorizing metal, it can do a double job. It can produce oxygen and color.

Barium     -Barium salts give a pleasant green color. Barium Nitrate is most 
            often used.
Strontium  -Strontium salts give a strong red color. Strontium Nitrate is a 
            very convenient material for red.
Sodium     -Sodium salts give an intense yellow color. So intense in fact that 
            any sodium compounds in a mixture will usually wash out other
            colorizers. As has been said, Sodium Nitrate absorbs moisture from 
            the air, and so is not really suitable to impart color. Instead, 
            Sodium Oxalate is usually used. This does not absorb lots of water, 
            but has the disadvantage of being very poisonous.
Copper     -Copper salts are used to give a blue color. Blue is the most 
            difficult color to produce, and it's usually not too spectacular. 
            Usually Copper Acetoarsenite (Paris Green) is used. This compound 
            contains arsenic, and is very poisonous. Since it still doesn't 
            produce a very memorable blue, it's often used with mercurous
            chloride, which enhances the color, but is also poisonous, and 
            expensive, to boot.
Potassium  -Potassium salts will give a delicate purple color, if they'e very 
            pure. The cheaper lab grades of potassium nitrate often contain 
            traces of sodium, which completely obscure the purple color. In 
            order to get the purple coloring, very pure grades must be used, 
            and you must be very careful to mix it in very clean vessels, and 
            scoop it from the supply jar with a very clean scoop. The color is 
            certainly worth the effort, if you can get it.


Some mixtures that burn in colors also contain binders, that hold the mixture 
together in a solid lump. These lumps are usually referred to as stars. The 
balls fired from a roman candle or the colorful showers sprayed from aerial 
bombs are examples of stars. Depending on the mixture, the binder is either a 
starch called dextrine or finely powdered orange shellac. A shellac-like 
material called red gum is also used on occasion. In some mixtures, the shellac 
powder also helps produce a nice color. Shellac mixtures are moistened with 
alcohol to get them to stick together. Dextrine mixtures are moistened with 
water.

If the colored mixture is to be used as a flare, it's just packed into a thin 
paper tube. If it's to be fired from a roman candle, it's usually extruded from 
a heavy tube by pushing it out with a dowel, and the pieces are cut off as the 
proper length pops out. Stars fired from an aerial bomb are usually made by 
rolling the moist mixture flat, and cutting it with a knife into small cubes.
Stars that are extruded are often called "pumped stars" those that are rolled 
out are "cut stars".

The following are formulas for mixtures that burn with various colors. Parts 
are by weight.

Red

Potassium Chlorate    9
Sulfur                2
Lampblack             1
Strontium Nitrate     9
bind with shellac
dissolved in alcohol


Blue

Potassium Chlorate    9         This one is inferior
Copper Acetoarsenite  2         Potassium Chlorate    12
Mercurous Chloride    1         Copper Sulfate        6
Sulfur                2         Lead Chloride         1
bind with dextrine              Sulfur                4
in water                        bind with dextrin in water


Green

Barium Chlorate       8         Barium Nitrate        3
Lampblack             1         Potassium Chlorate    4
Shellac Powder        1         Shellac Powder        1
bind with alcohol               Dextrine              1/4
                                Bind with alcohol

Yellow

Potassium Chlorate    8         Potassium Chlorate    8
Sodium Oxalate        3         Sodium Oxalate        4
Lampblack             2         Shellac Powder        2
Bind with shellac in            Dextrine              1
alcohol or dextrine             Bind with alcohol
in water


White

Potassium Nitrate     6
Sulfur                1
Antimony Sulfide      2
bind with dextrine in
water


Orange

Strontium Nitrate     36
Sodium Oxalate        8
Potassium Chlorate    5
Shellac Powder        5
Sulfur                3
Bind with alcohol


Purple (ingredients must be very pure)

Potassium Chlorate    36        This one has more of a lilac color
Strontium Sulfate     10        Potassium Chlorate    38
Copper Sulfate        5         Strontium Carbonate   18
Lead Chloride         2         Copper Chloride       4
Charcoal              2         Lead Chloride         2
Sulfur                12        Sulfur                14
bind with dextrine in           bind with dextrine in water
water


Brilliant White

Potassium Perchlorate 12
Aluminum Dust         4
Dextrine              1
Bind with water  


Golden Twinkler Stars - Falls through the air and burns in an on and off 
  manner. The effect is spectacular. A pumped or cut star.

Potassium Nitrate     18
Sulfur                3 
Lampblack             3
Aluminum Powder       3
Antimony Sulfide      3
Sodium Oxalate        4
Dextrine              2
Bind with water

Zinc Spreader Stars - Shoot out pieces of burning zinc and charcoal. These 
  stars are much heavier than usual, and require larger charges if they're to 
  be fired from a tube.

Zinc Dust             72
Potassium Chlorate    15
Potassium Dichromate  12
Granular Charcoal     12
Dextrine               2
bind with water

Electric Stars - Stars that contain aluminum powder

Potassium Nitrate     15        Potassium Chlorate    60
Aluminum, fine        2         Barium Nitrate        5
Aluminum, medium      1         Aluminum, fine        9
Black Powder          2         Aluminum, medium      4
Antimony Sulfide      3         Aluminum, coarse      3
Sulfur                4         Charcoal              2
bind with dextrine in           Dextrin               5
water                           bind with red gum in 
                                water
Potassium Perchlorate 6
Barium Nitrate        1         Potassium Perchlorate 4
Aluminum              20        Aluminum, medium      2
Dextrin               1         Dextrin               1
bind with shellac in            bind with shellac in alcohol
alcohol


Simpler Zinc Spreaders

Potassium Nitrate     14        Potassium Chlorate    5
Zinc Dust             40        Potassium Dichromate  4
Charcoal              7         Charcoal, medium      4
Sulfur                4         Zinc Dust             24
bind with dextrine in           bind with dextrine in water
water


Willow Tree Stars - Use large amounts of lampblack -- too much to burn fully.
  Gives a willow tree effect.

Potassium Chlorate    10
Potassium Nitrate     5
Sulfur                1
Lampblack             18
bind with dextrine in water

In future files, we'll look at using these mixtures to produce roman candles, 
aerial bombs, and other effects. As always, don't forget that it's just plain 
stupid to go buying all these materials from one chemical supply house. When 
you buy it all as a group, they know what you plan to do with it, and they keep 
records. If anyone goes investigating the source of homemade fireworks and 
checks with your supplier, there will be a lead straight to you. Be sure to 
cover your tracks.