48 replies to this topic

[aapua]

Hi everybody and greetings from Estonia!

First. Forget about things like "I have only KNO3 and sulphur and coal and sugar, but would somebody pleas tell me how I can make blue, green and red colors with only these chemicals?" Does not matter, you do pyrotechnical stuff for your own pleasure or for others to see, you need some special equipment and chemicals. The part of technology is a weak side to me, but I know pretty something about chemistry and pyrochemistry.

A suggestion. There are pretty many sites where you can find a huge amount of mixtures, some of them are really good, some are not. But, if you happen to find a russian site, you are lucky one. Cannot say it about all russian sites, but at least some of them have materials stolen or just got from different research labs of Russia. And these works are good.

A good site (it worked a week ago, but last few days it was down. I hope it would be fixed again) is www.pirotex.by.ru - if you happen to read russian.

Now finally about chemicals.

UROTROPINE. I would say it is the God's gift. Use it as a fuel and you see what I'm talking about. One more good thing - it helps you make mixture, that gives big flame, but burns very slowly. Only be careful - the burning of urotropine is something different. First it melts, and if you use too much of it, it kills the flame and the reaction. But, using A BIT too much gives extra golden sparks, so the effect in the sky is markable. Always would be good to use al-powder in the mixture. It helps to "carry" the burning zone. Don't be afraid - the color becomes even more bright, but remains good and clear. The wellknown fact is (although the mechanism of it is not known) that you can make good colors even with the simple stable chlorides - BaCl2, SrCl2, CuCl2. Use urotropine, the chosen cloride and magnesium powder (works pretty well with aluminium powder too). This is useful, when you don't have nitrates or something else. But, the question of oxygen source remains.
Sad thing might be that in order to get good clean colors, it would be nice to have some AMMONIA PERCHLORATE. Although potassium is very weak colorant, I say it just destroys the possible good colors. Especially bad is KClO3.
As a binder, I would suggest to use dextrin. The drying time is long, OK, but the slower the drying process, the better the results. If you have mixtures containing huge amount of aluminium powder, you may have noticed it is pretty complicated to mix it with water. It is a good way to solve the problem - use first a small amount of acetone, mix it well, let it dry a bit, and only then add water. Now your work is easier. For the mixtures with big amounts of C dust you may do the same.

Few mixtures as well.
RED.
Sr(NO3)2 - 35
NH4ClO4 - 35
Al powder - 10-15
Urotropine - 10-15
Dextrine - 5

For beautyful GREEN simply replace Sr(NO3)2 with Ba(NO3)2.

The blue color is something that amazes me. In this case, urotropine does not give so especially good results (but they are good anyway). Calomel is good, but expensive and poisonous. What you may find, is copper acetate - it works very well, CuO and Cu(NO3)2 do well, too. What I use, is something odd - Cu(NO3)2 * 3CuO. Of all tested chemicals it gives the best result. A good BLUE with simple chemicals:
NH4ClO4 - 40
CuO - 10
Cu-acetate - 10
Cu(NO3)2 - 15
Urotropine - 12
Al powder - 8
Dextrine - 5

For YELLOW I use sodium oxalate.
Just play with chemicals - use urotropine to get big flame, have 5 - 20% sodium oxalate in the mixture, choose oxygen source and that's it.

For the beautiful ORANGE take the mixture for red, and add +1%dextrine and +5-7% Na2C2O4 (sodium oxalate).

Somebody asked about PINK?
This is my way:
Sr(NO3)2 - 30-35 (32)
NH4ClO4 - 30-35 (32)
Al powder - 25-35 (30)
Dextrin - 5-10 (6)
Burn VERY bright, but a little bit too fast. I call the color BABY PINK.

SAFETY, SAFETY and once again SAFETY.
These chemicals together - urotropine, al-powder, ammoniumperchlorate and some nitrate - are reactive when moist. Just smell it - you can feel ammonia? This is what I'm talking about. Do the mixture only in small amounts and at once do the work with it till the end. The more water you use, the higher is danger.
Do an experiment - make a mixture, for example for red color, add water to get a mixture like a creamy soup and let is stay. Soon the smell of ammonia grows bigger, the mixture starts to bubble, the mixture "grows" and hardens. When you touch it, you can feel it has become hot. Wait even more and you can see self-ignition. I just want to say that when you use these chemicals, be careful and dry your ready-made stars ABSOLUTELY COMPLEATLY.

Few words about covering the stars.
There is an interesting chemical I use. K3[Fe(CN)6] or red blood salt (this is direct translation from both estonian and russian. I have no idea, how you might call it in english). Anyway, it is very common and cheap chemical.

The primer I use is:
KClO4 - 50
K3[Fe(CN)6] - 20-25
C dust - 20-25
Dextrine - 5-10

I cover the stars 3 times.
1. Take 2-3 parts of star mixture and 1 part of primer.
2. Take 1 part of star mixtur and 2 parts of primer.
3. Use only primer (I often decrease the amount of dextrine for the last covering).
The stars ignite very well and easy, the main color would be seen immediately and there is a very nice tale of golden sparks behind the flying star.

And the last but not least. I said urotropine stars give big, brigth flame and burn slowly. The star (without primer, just the main mixture) of about 5x5x5mm burns up to 7 seconds. Now make pump or cut stars, covering only one side with the primer (there are many ways to do that). For the cylindrycal 75mm b**b I use up to 300 gr of small, longlasting stars (maybe 500-1000 pcs). Can you imagine the picture in the sky?!?!

[BigG]

Hi everybody and greetings from Estonia!

First. Forget about things like "I have only KNO3 and sulphur and coal and sugar, but would somebody pleas tell me how I can make blue, green and red colors with only these chemicals?" Does not matter, you do pyrotechnical stuff for your own pleasure or for others to see, you need some special equipment and chemicals. The part of technology is a weak side to me, but I know pretty something about chemistry and pyrochemistry.

A suggestion. There are pretty many sites where you can find a huge amount of mixtures, some of them are really good, some are not. But, if you happen to find a russian site, you are lucky one. Cannot say it about all russian sites, but at least some of them have materials stolen or just got from different research labs of Russia. And these works are good.

A good site (it worked a week ago, but last few days it was down. I hope it would be fixed again) is www.pirotex.by.ru - if you happen to read russian.

Now finally about chemicals.

UROTROPINE. I would say it is the God's gift. Use it as a fuel and you see what I'm talking about. One more good thing - it helps you make mixture, that gives big flame, but burns very slowly. Only be careful - the burning of urotropine is something  different. First it melts, and if you use too much of it, it kills the flame and the reaction. But, using A BIT too much gives extra golden sparks, so the effect in the sky is markable. Always would be good to use al-powder in the mixture. It helps to "carry" the burning zone. Don't be afraid - the color becomes even more bright, but remains good and clear.  The wellknown fact is (although the mechanism of it is not known) that you can make good colors even with the simple stable chlorides - BaCl2, SrCl2, CuCl2. Use urotropine, the chosen cloride and magnesium powder (works pretty well with aluminium powder too). This is useful, when you don't have nitrates or something else. But, the question of oxygen source remains.
Sad thing might be that in order to get good clean colors, it would be nice to have some AMMONIA PERCHLORATE. Although potassium is very weak colorant, I say it just destroys the possible good colors. Especially bad is KClO3.
As a binder, I would suggest to use dextrin. The drying time is long, OK, but the slower the drying process, the better the results. If you have mixtures containing huge amount of aluminium powder, you may have noticed it is pretty complicated to mix it with water. It is a good way to solve the problem - use first a small amount of acetone, mix it well, let it dry a bit, and only then add water. Now your work is easier. For the mixtures with big amounts of C dust you may do the same.

Few mixtures as well.
RED.
Sr(NO3)2 - 35
NH4ClO4 - 35
Al powder - 10-15
Urotropine - 10-15
Dextrine - 5

For beautyful GREEN simply replace Sr(NO3)2 with Ba(NO3)2.

The blue color is something that amazes me. In this case, urotropine does not give so especially good results (but they are good anyway). Calomel is good, but expensive and poisonous. What you may find, is copper acetate - it works very well, CuO and Cu(NO3)2 do well, too. What I use, is something odd - Cu(NO3)2 * 3CuO. Of all tested chemicals it gives the best result. A good BLUE with simple chemicals:
NH4ClO4 - 40
CuO      - 10
Cu-acetate - 10
Cu(NO3)2 - 15
Urotropine - 12
Al powder - 8
Dextrine - 5

For YELLOW I use sodium oxalate.
Just play with chemicals - use urotropine to get big flame, have 5 - 20% sodium oxalate in the mixture, choose oxygen source and that's it.

For the beautiful ORANGE take the mixture for red, and add +1%dextrine and +5-7% Na2C2O4 (sodium oxalate).

Somebody asked about PINK?
This is my way:
Sr(NO3)2 - 30-35    (32)
NH4ClO4 - 30-35    (32)
Al powder - 25-35  (30)
Dextrin - 5-10        (6)
Burn VERY bright, but a little bit too fast. I call the color BABY PINK.

SAFETY, SAFETY and once again SAFETY.
These chemicals together - urotropine, al-powder, ammoniumperchlorate and some nitrate - are reactive when moist. Just smell it - you can feel ammonia? This is what I'm talking about. Do the mixture only in small amounts and at once do the work with it till the end. The more water you use, the higher is danger.
Do an experiment - make a mixture, for example for red color, add water to get a mixture like a creamy soup and let is stay. Soon the smell of ammonia grows bigger, the mixture starts to bubble, the mixture "grows" and hardens. When you touch it, you can feel it has become hot. Wait even more and you can see self-ignition. I just want to say that when you use these chemicals, be careful and dry your ready-made stars ABSOLUTELY COMPLEATLY.

Few words about covering the stars.
There is an interesting chemical I use. K3[Fe(CN)6] or red blood salt (this is direct translation from both estonian and russian. I have no idea, how you might call it in english). Anyway, it is very common and cheap chemical.

The primer I use is:
KClO4          - 50
K3[Fe(CN)6]  - 20-25
C dust          - 20-25
Dextrine      - 5-10

I cover the stars 3 times.
1. Take 2-3 parts of star mixture and 1 part of primer.
2. Take 1 part of star mixtur and 2 parts of primer.
3. Use only primer (I often decrease the amount of dextrine for the last covering).
The stars ignite very well and easy, the main color would be seen immediately and there is a very nice tale of golden sparks behind the flying star.

And the last but not least. I said urotropine stars give big, brigth flame and burn slowly. The star (without primer, just the main mixture) of about 5x5x5mm burns up to 7 seconds. Now make pump or cut stars, covering only one side with the primer (there are many ways to do that). For the cylindrycal 75mm b**b I use up to 300 gr of small, longlasting stars (maybe 500-1000 pcs). Can you imagine the picture in the sky?!?!

very nice - unfortunetly - it is close to impossible to get ammonium perchlorate in the UK.

[alany]

FeK3(CN)6 is usually called Potassium Ferricyanide.

I have quite a lot of it for photochemistry. It is commonly used as a bleach and as part of cyanotype forumulations. I've read that is is also used is some blasting BP compositions, but I haven't got around to trying that yet. It has certian catalytic properties that might be useful in pyrotechnics.

[Creepin_pyro]

RED.
Sr(NO3)2 - 35
NH4ClO4 - 35
Al powder - 10-15
Urotropine - 10-15
Dextrine - 5

I was under the impression that mixing NH4ClO4 with aluminium powder was a very bad idea, due to the possibility of forming Ammonium Chlorate

[aapua]

I was under the impression that mixing NH4ClO4 with aluminium powder was a very bad idea, due to the possibility of forming Ammonium Chlorate

Well, as you might know, this mix - ammoniumperchlorate + al powder - is so called solid rocket fuel. And I mean real rockets - the ones flying to the space. Once I happened to get a few NASA formulaes, and this was one of them

[Richard H]

Our friend is correct. AP and Aluminium (often atomised) is regularly used in composite motor formulations. I use such commercially manufactured motors on a regular basis.

[BigG]

Mr C-Pyro has a grain of truth in his word. Is general - ammonium perchlorate mixtures are safer when mixed with non-metallic fuel. Most modern formulations will avoid such a combination. aapua - note that NASA got quite a few formulas that are very sensitive and should be attempted only in a lab. (Richard - is my memory serves me right, consumer class solid motors use either black powder or ammonium perchlorate / charcoal mxtures, not ammonium perchlorate aluminium mixtures.... I might be wrong)

As for Potassium Ferricyanide ? again, old school. While still used, such chemicals are on the way out (in fact, all the arsenide and cyanide families get the thumb down) as safer and similar in efficiency formulations are found. For a primer ? I would not see the need for such chemicals at all.

Edited by BigG, 01 February 2005 - 12:11 PM.

[Richard H]

Aerotech and ProX motors are almost always based on AP / Alu, as well as a rubber binder such as HTPB or some form of epoxy system. The propellents are often quite rubbery in appearance, and burn with a bright white flame in the open.

[Creepin_pyro]

Our friend is correct. AP and Aluminium (often atomised) is regularly used in composite motor formulations. I use such commercially manufactured motors on a regular basis.

Don't know where I got that idea, then

Can I now assume it's safe to mix these without risk of producing Ammonium Chlorate?

[aapua]

Don't know where I got that idea, then

Can I now assume it's safe to mix these without risk of producing Ammonium Chlorate?

There is a simple rule: KEEP ALL YOUR STUFF DRY ALL THE TIME!!! Watch over your storage conditions.
Pyrochemical reactions are so-called zone-reactions, the one you are afraid of seems to be more ionic. And even then - basic rule is, that reactions don't stop in the middle. Perchlorates are more stable and less reactive than chlorates, so formation of Al2O3 in this mixture should give you NH4Cl instead of NH4ClO3.

Few more words I can add about chlorates. I've done a little study at the university and find out that in the normal processes the burning of the system chlorate / fuel goes through the steps chlorate -> perclorate -> ready product. Only few chemicals prevented the formation of perchlorate first (by the way -
K3[Fe(CN)6] was one of them).

Dry, solid systems, especially when not sensitive to shock, are mostly very stable. But NEVER mix ammoniumperchlorate with potassiumchlorate, this mixture gives you something you actually don't want.

[aapua]

As for Potassium Ferricyanide ? again, old school. While still used, such chemicals are on the way out (in fact, all the arsenide and cyanide families get the thumb down) as safer and similar in efficiency formulations are found. For a primer ? I would not see the need for such chemicals at all.

My logic and reasons: similar ignites the similar. As a bursting charge (I'm sorry if I used wrong word. I mean the charge that works there, up in the sky inside the shell to throw the stars all over) I use mixture
KClO4 - 50
K3[Fe(CN)6] - 20 - 25
C dust - 25
Al powder - 0 - 5

This mixture is FAR more powerful than BP, but ignites easyly than KClO4/Al mixture.
Second, there will be no effect like washed-away colors.
Third, especially good is that mixture for chrysanthemum-effect. For peony, when no tail behind the star is wanted, it's no good.

Edited by aapua, 01 February 2005 - 01:39 PM.

[BigG]

Don't know where I got that idea, then

Can I now assume it's safe to mix these without risk of producing Ammonium Chlorate?

I don't know the answer for that - but again, always remember that in non-lab conditions, moisture is very likely to creep in, and can initiate reactions. It is most likely that those who work in a laboratory have a much more chemical friendly environment.

[aapua]

I don't know the answer for that - but again, always remember that in non-lab conditions, moisture is very likely to creep in, and can initiate reactions. It is most likely that those who work in a laboratory have a much more chemical friendly environment.

Even not gonna argue. Moisture does cause self-ignitions sometimes and it is almost impossible to avoid it. For potential dangerous mixtures - replace aluminium with the so-called dark or Pyro-aluminium. In this case every single aluminium particle is covered, if I'm correct, with carbon, and the possible danger is not so high.
I also have found in some cases pretty wise to add some paraffin to the mixture.
It keeps the moisture away, and the pellets are very easily compesseable. Heat the mixture gently until the paraffin melts, mix it really well and then continue as usually.

[BigG]

My logic and reasons: similar ignites the similar. As a bursting charge (I'm sorry if I used wrong word. I mean the charge that works there, up in the sky inside the shell to throw the stars all over) I use mixture
KClO4? ? ? ? ? - 50
K3[Fe(CN)6] - 20 - 25
C dust? ? ? ?  -? 25
Al powder? ? - 0 - 5

This mixture is FAR more powerful than BP, but ignites easyly than KClO4/Al mixture.
Second, there will be no effect like washed-away colors.
Third, especially good is that mixture for chrysanthemum-effect. For peony, when no tail behind the star is wanted, it's no good.

Of course this mixture is stronger then BP... again, while I can see the logic, I can?t see why you will need K3[Fe(CN)6] in there. You can improve ignobility by adding small amount of charcoal or using a thin layer of BP premier. While Potassium ferricyanide is not particularly hazardous, it just adds an element that I?m not sure contribute much. Then again, I guess I will need to try it myself

What shell size do you use it on?

Edited by BigG, 01 February 2005 - 01:54 PM.

[aapua]

Of course this mixture is stronger then BP... again, while I can see the logic, I can’t see why you will need K3[Fe(CN)6] in there. You can improve ignobility by adding small amount of charcoal or using a thin layer of BP premier. While Potassium ferricyanide is not particularly hazardous, it just adds an element that I’m not sure contribute much. Then again, I guess I will need to try it myself

BP causes almost every time the wash-away color effect, especially for the red, that goes from red to dark salmon. My experiences say, don't use KNO3 in primers!!!