Official pyrotechnics thread!

[RyanJ]

The chemistry of pyrotechnics?

 

I've always been interested in fire and fireworks as I know a lot of other people are, I think this is what actually sparked (HaHaHa, spark ignites explosives...) my interest in chemistry.

I would also like to show through this thread that people are sensible with their knowledge and chemists is a bomb-crazed maniacs!

 

So I was thinking about a thread related to pyrochemistry and let me state before we start this is not a thread related to the making of any explosive / pyrotechnic devices just a discussion on how they came to the recipes (Not actually positing them) and related subjects.

 

I was thinking we could talk about:

• Why xxx is used in firework production - Pretty obvious.
  
• The chemistry of pyrotechnics - Why do these work the way they do, what are the reactions that go on in the centre of those fireworks?
  
• Calculations to do with the above - How would you calculate the blast radius of an explosion from 20g of TNT? Mathematical representations of the above points. How much energy is released when 20g of TNT is detonated?
  
• Why are things explosive - Why does Ammonium Triiodide explode and why is it so unstable? Why are some of these so unpredicatable?
  
• Why do fireworks work? - From a chemistry, mathematical or physics aspect! No money rubbish here please, we are scientists not bankers
  
• Hazards related to fireworks / explosives - Do all those metals used in Fireworks damage peoples health? Do they disrupt radio signals to phones in long term? Do they build up in the soil and air?
  

 

Thread Rules:

• Read this thread before you post here!
  
• No discussion as to the making of explosive/pyrotechnic devices in any way shape or form. This includes links to other websites with the information! Discussion of the chemicals are permitted within reason. The methods of production must not be posted.
  
• No discussion of any prohibited chemicals and or devices (production etc.) This includes links to other websites with the information. Formulas may be posts as long as they don't relate to the production of the substance in question.
  
• Chemistry, mathematical and physics aspects only (general science).
  
• Keep to the forum TOS at ALL times!
  

 

So the general rule is you can post anyhting as long as it does not tell people how to make the chemical in question or a device used to deploy it.

 

And let me state again this is not a thread about making these devices, this thread would be good as long as it is kept on topic and away from the areas prohibited by the TOS as was intended by me I don't see why this topic would be banned as long as the people in this thread are responsible with that they say and post.

 

A lot of people should be interested in this thread for the chemistry aspects so let me just say that if this is not acceptable to the moderators then please remove it is this thread is acceptable to the mods then if you have any more rules please add them!

 

A warning from woelen:

 

We'll keep an eye on it. If things really go out of hand' date=' then the persons, responsible for that will be warned.

[/quote']

 

Cheers,

 

Ryan Jones

[RyanJ]

I'll start the thread then!

 

First here are some of the oxidisers used in fireworks:

 

[ce]NaNO3[/ce] - Sodium Nitrate

[ce]KNO3[/ce] - Potassium Nitrate

[ce]KClO3[/ce] - Potassium Chlorate

[ce]KClO4[/ce] - Potassium Perchlorate

[ce]KMnO4[/ce] - Potassium Permanganate

 

There are others too, will add them as I collect then

A question related to the above list. Can soemone explain why these are so good as oxidisers?

 

Also, seeing as the other thread was deleted I'll ask this again so someone can reply (Woelen probably ):

 

Wht makes the green colour in fireworks? I know white is commonly magnesium or sometimes aluminium but I have no idea what green is

 

Cheers,

 

Ryan Jones

 

Edit: Fixed some chemical errors

[biohazard87]

Copper is a good way to make green coluors. I also think you can use strontium too. But copper is the best thing to use.

[YT2095]

Copper is a good way to make green coluors. I also think you can use strontium too. But copper is the best thing to use.

 

utter garbage!

 

Copper is for Blues and green enhancers only, Strontium would screw it up entirely as that`s for RED!

Barium with a Chlorine donor (parlon or PVC) is your Green.

[biohazard87]

I asked a chemical Eneginier that also teaches AP chem. She told me that coper will make green flames. I have also done this as a project.

[RyanJ]

utter garbage!

 

Copper is for Blues and green enhancers only' date=' Strontium would screw it up entirely as that`s for RED!

Barium with a Chlorine donor (parlon or PVC) is your Green.[/quote']

 

Barium ei? I thought the Barium salts were very toxic?

 

Anyway, what type of exotic colours can you make? The possabilities seen unlimited by combining the various other types e.g. Charcoal and a copper salt should also make a green colour as charcoal burns with an orange/yellow flame and copper salts with a blue one

 

Also, do these salts affect the way in which the reactants burn? Do they for example slow down the reaction at all or reduce the net temperature produced?

 

biohazard87: I think copper will make a green flame only if it is its oxide that is burning although I am not shure about that!

 

Cheers,

 

Ryan Jones

[YT2095]

copper is used for blue colors, and as I stated green enhancers/moderators, but primarily for Blue.

 

Barium IS toxic, but not much more than Copper as a material, and it`s not Cumulative either (unlike Lead, Mercury, Cadmium etc...)

sensible precations taken with it as with any other chem will ensure your safety

 

as for colors you name it, it can be done ))

that`s the most beautifull part about it, it`s like mixing paints and the sky is your blank paper/canvas

 

and yes they do have an effect on how certain compos burn, that again is another tool you can use

[RyanJ]

and yes they do have an effect on how certain compos burn' date=' that again is another tool you can use [/quote']

 

So does that mean it can have an effect like a whistle effect for example or to delay certain "layers" in things like roman candles? Say you could then make one level burn faster than the next.

 

How about the oxidants, what is the difference between the ones I listed in my second post.

Say for example you were using Barrium Sulphate:

 

[ce]NaNO3 + BaSO4[/ce] = how much energy compred with: [ce]KNO3 + BaSO4[/ce]?

 

Which one is the most effective and why?

I suppose in the "real" world money has just as much effect on the ingredients as their effectivness

And it makes sence that Barium is not a cumulative salt, I should ahve thought about that earlier. If it were then it would not be allowed to be used. So I presume that its safe to have a small dose of this once a year then?

 

Cheers,

 

Ryan Jones

[YT2095]

So does that mean it can have an effect like a whistle effect for example or to delay certain "layers" in things like roman candles? Say you could then make one level burn faster than the next.

 

that`s exactly what I mean

this is where the Physics and a few calcs come into play, with burn rates and materials used for ideal timing.

 

as for the oxidisers, again, that all depends on the effect you want and the compostions involved, some maybe incompatible for instance, some may degrade over time or alter a color adversely and so on....

 

there`s like a million and one things to factor in when designing a firework, seriously, there really is!

[RyanJ]

that`s exactly what I mean

this is where the Physics and a few calcs come into play' date=' with burn rates and materials used for ideal timing.

 

as for the oxidisers, again, that all depends on the effect you want and the compostions involved, some maybe incompatible for instance, some may degrade over time or alter a color adversely and so on....

 

there`s like a million and one things to factor in when designing a firework, seriously, there really is![/quote']

 

I suppose they have to think of just about everything for safety reasons.

 

Is there an actual method to calculate how long it will take [ce]X[/ce] substance to react with [ce]X[/ce] other substance in that case? Or do most of the companys just try trial and error in a lot of the cases?

 

Also, I know that varying the mesh size of the particles also affects the results, obviously finer = largr surface area = faster reaction rate. Do the larger particles make those pretty fountain effects? Like the glowing waterfall fireworks for example that glow a bright white (Probably magnesium) use these large grains or are those another effect of a special reaction?

 

This could very well turn out to be an interesting thread!

YT, have you ever worked in a fireworks factory? You seen to know a lot about them!

 

Cheers,

 

Ryan Jones

[YT2095]

the waterfall effects use a slightly larger mesh Titanium and Alu, rarely is Mg used (has a poor shelf life) there also several other things going on too, there`s Micro "Stars" if you like, and they also have their own compostition (usualy made in a tumbler) the course mesh Ti or Al is used as a Hazing effect, the real crackly brighter ones are the micros "stars" (often a thermit reaction with low activation and the fuel binder added for ignition ease).

 

my work history is nothing to do with anyone here, I decline to answer that other question.

[RyanJ]

the waterfall effects use a slightly larger mesh Titanium and Alu' date=' rarely is Mg used (has a poor shelf life) there also several other things going on too, there`s Micro "Stars" if you like, and they also have their own compostition (usualy made in a tumbler) the course mesh Ti or Al is used as a Hazing effect, the real crackly brighter ones are the micros "stars" (often a thermit reaction with low activation and the fuel binder added for ignition ease).

[/quote']

 

Makes sence! Things like flash powder, using fine mesh aluminium, burn really, really fast. By using a slightly larger mesh size you could then make the effect last longer depending on the size of the particle! Quite clever

 

my work history is nothing to do with anyone here' date=' I decline to answer that other question.[/quote']

 

Sorry, did not mean to offend you there

And it was a rhetorical question, it was not meant to be answered. What I should have said was your knowledge seems to indicate that you have worked with pyrotechnics in the past.

 

Cheers,

 

Ryan Jones

[YT2095]

Makes sence! Things like flash powder' date=' using fine mesh aluminium, burn really, really fast. By using a slightly larger mesh size you could then make the effect last longer depending on the size of the particle! Quite clever

 

 

 

Sorry, did not mean to offend you there

And it was a rhetorical question, it was not meant to be answered. What I should have said was your knowledge seems to indicate that you have worked with pyrotechnics in the past.

 

Cheers,

 

Ryan Jones[/quote']

 

with regard to FP the Visual would last longer, but the sound and rupture would lack Brissance, we`re only talking micro-seconds here anyway, but that`s what would happen.

and for the other part, no offence taken at all, as for pyro work I have about 27 years experience behind me and hopefully many times that in front of me too, and yeah, I still have all my Fingers!

[RyanJ]

Do rockets use a flash-bang mixture? They shoot up rapidly then explode, this suggests some sort of flash powder or maybe a custom gunpowder mix?

 

How do they know how long the reaction will take to complete? Is there a formual that allows one to work that out?

 

Cheers,

 

Ryan Jones

[YT2095]

a rocket engine will burn from the fuse end up to the last end bit in the tube or of the grain, that then (when it reaches the other end) ignites either a slow ball star, delay charge, a fuse or the mix directly (depending on the effect).

[RyanJ]

Ah, right! thanks YT!

 

Onto the next quesiton I have - what type of Firefowk effects cna you have? I know thinkgs like Flash-Bang, Flash, etc but are there any more exptic type results?

 

Also, this is more of a general question than a chemistry one but how do they make thoser fireworks that produce patterns when thy explode? Those thigns are really impressive!

 

Cheers,

 

Ryan Jones

[Phi for All]

I asked a chemical Eneginier that also teaches AP chem. She told me that coper will make green flames. I have also done this as a project.

NEVER question YT2095 when it comes to exploding things.

 

http://www.ag.ohio-state.edu/~twig/other/html/063096.html

http://www.pbs.org/wgbh/nova/transcripts/2903_firework.html

[RyanJ]

NEVER question YT2095 when it comes to exploding things.

 

http://www.ag.ohio-state.edu/~twig/other/html/063096.html

http://www.pbs.org/wgbh/nova/transcripts/2903_firework.html

 

Did YT write those or was he in them, in either case !

 

I would never question YT anyway, he knows his stuff in this fiend with no doubts

 

Cheers,

 

Ryan Jones

[YT2095]

Ah' date=' right! thanks YT!

 

Onto the next quesiton I have - what type of Firefowk effects cna you have? I know thinkgs like Flash-Bang, Flash, etc but are there any more exptic type results?

 

Also, this is more of a general question than a chemistry one but how do they make thoser fireworks that produce patterns when thy explode? Those thigns are really impressive!

 

Cheers,

 

Ryan Jones[/quote']

 

what the hell did you just say/ask????

[RyanJ]

what the hell did you just say/ask????

 

Ok....

 

What type of firefork effects can you have?

I know thinkgs like Flash-Bang, Flash, fountain, etc. but are there any more exotic types?

 

Also, this is more of a general question than a chemistry one but how do they make those fireworks that produce patterns when they explode like shapes and the like? Those thigns are really impressive!

 

Cheers,

 

Ryan Jones

[insane_alien]

about the copper thing. copper really only produces a green flame when it is burned slowly and usually in a solid lump when you powder it and react it fast then it looks more blue. YT is (yet again) right on this. even when copper burns green its a crap(my opinion) green.

[RyanJ]

about the copper thing. copper really only produces a green flame when it is burned slowly and usually in a solid lump when you powder it and react it fast then it looks more blue. YT is (yet again) right on this. even when copper burns green its a crap(my opinion) green.

 

That explains why when someone threw a copper pipe on a bonfire (No, it was not me) there was a very faint green flame there and yea it looked bad!

 

YT is always right! Its his job to always be right (and all the otehr mods too!)

 

Cheers,

 

Ryan Jones

[woelen]

Well Ryan, here I am again . My remarks on the green color I did in the previous version of the thread already have been covered much better by YT, so I'll not elaborate on that again.

 

I'm not a real fireworks expert, mainly due to the fact that pyrotechnics is forbidden in the Netherlands. Yes, forbidden, period.

 

I did some small-scale experiments, however.

 

With sulphur you can make beautiful blue blue. I once made some liquid sulphur, made it burn and then caused a small explosion in it. This gives a spray of beautiful ghostly blue flares of the burning molten sulphur. I'm not sure, whether this can be created in real fireworks, but the effect is neat.

 

 

As far as I know the following colors can be obtained from the salts of these metals:

 

barium - (greyish pale) green (YT knows how to make it brilliant )

strontium - beautiful bright red

calcium - pale red

lithium - red

 

From metals themselves, brilliant flares can be produced:

 

magnesium metal

aluminium metal

 

magnesium salts and aluminium salts do not add color to compositions and in fact are quite useless.

 

 

I once did a small experiment with K2CO3 and KNO3.

A really remarkable mix is K2CO3 / KNO3 and S. It can be made to explode, even in the open without confinement. You need a special preparation, but I'll not elaborate on that over here (k3wls also read this).

This is a very remarkable reaction, because K2CO3 is not an oxidizer at all. I do not understand, why this mixture explodes and does not simply burn like BP.

 

My last experience with energetic compounds was with azides.

I was so lucky to obtain some sodium azide (NaN3), a very hard to obtain chem. Wow, that is nice stuff, not on its own, but it can be used to make compounds like Pb(N3)2 and Cu(N3)2. These are explosive compounds, which can be made to detonate, even when wet. These are a little scary though.

 

Right now I'm doing a larger project on nitronic acid, nitrolic acid, nitronates, and the nitrolates. These are derived from the aci-form of nitromethane, a very common fuel enhancer. If I have interesting results, then I'll post them here. However, making these at home is not that easy, because they require a lewis acid-base reaction under totally anhydrous conditions.

[YT2095]

how do they make those fireworks that produce patterns when they explode like shapes and the like?

Cheers' date='

 

Ryan Jones[/quote']

 

it`s basicly a 3D construct in miniature, often spherical around a bursting charge in what we call a Shell, sometimes they`re also cylindrical, but that`s mainly the cheap end of the market for home use and not Display fireworks.

the shells are normaly Mortar launched but on occasion rocket launched too, again, as the rocket fuel expires it ignites a delay fuse (the deployment method still has momentum and the fuse waits long enough until there`s no longer Upwards travel), the bursting charge is then lit by this delay fuse, from that point the Stars (moulded color or effect compositions) have their outer coating lit (often ordinary Black powder with sharp edges) and the burst charge explodes the shell in all 720 degrees thowing these now outer coating lit STARS, this all takes longer to type than it does to happen!

the coating ignites the star and you see the effect

 

sometimes it`s not a "Star" it can be doped fuse clusters or mini gerbs etc...

 

it really is beyond the scope of a single post to tell all that`s Possible )

[RyanJ]

YT2095: Thats quite a complciated setup, no wonder these types of fireworks cost a lot! I bet it must take a lot of work to get one of these things right then?

So they are basically like mini-fireworks inside a larger firework that when the larger one explodes a fuse on the smaller ones are set off so that when they are in the correct possitions they all explode making a pattern! Does that mean that the fuse lengths of each of the seperate parts need to vary accordingly?!

 

woelen: You can get chemicals easily there but you can't do any pyro? That sucks so bad!

Nice set of descriptions there too! I've never actually worked with or even seen any azides but I'm heared they can be quite dangerous at times.

And I'm shure everyone will be interested to hear the results of your experiment!

 

When I started home chemistry a few weeks ago I decided to talk to the local police about whats permitted and whats not - they were happy that I did actually. They basically said anything that does not hurt or disturb people after a certain time - anything below the level that could hurn someone is acceptible without a lisance. Fortunatly I do not intend to mess with this stuff without training first (Some kid arround here did try and mamaged to hurt himself quite badly because he did not know what he was doing)!

 

I have a question for who ever can answer it: why is Sulphur used in a mix? I'm not shure it actually provides any colour so does it do something for the actual reaction like regulate speed or something?

 

Cheers,

 

Ryan Jones