Flash Not Green!

[THErAPIST]

OK.. I know that we are all getting sick of seeing flash threads but when was the last time we all talked about COLORED flash? I had a go at making some green flash earlier but instead of flashing green, it flashes a blinding white. Don't get me wrong here.. Good flash is great and I;m fine with having my white flash, but I'm confused as to why it doesnt flash green.

The formula I used came from the nice little fireworks PFP database and is as follows.

Visser green flash
Potassium perchlorate 43
Barium nitrate 21
Aluminum, Dark Pyro 36

I followed the percentages EXACTLY and I have always been inclined to believe that barium compounds gave off a green light in exothermic reactions, but it seems that I was wrong. I'm not really bothered by the fact that its not green, ut I'm a little confused. I think I may have a go at red flash using strontium nitrate... Maybe THAT would work eh?

[nbk2000]

Perhaps it is too "white" of a green to be clearly seen? Too bright a light can overwhelm the color sensing cones in the retina. Try viewing it from a distance, at night.

[THErAPIST]

Nope. I dampened a little bit of it and then stuck a fuse into it to test it. I lit the fuse and then ran down the road and watched it. It burned alot slower and i was able to watch it from about 2 houses down. It was as white as could be. Now you see why I am confused?

[frogfot]

I heard that Ba alone burns white, therefore all green stars with barium salts contain a chlorine donor. Maby your comp needs some fine PVC..

[THErAPIST]

I also heard that potassium perchlorate works well with blue and green colored comps frog, but I think I'll add some PVC to see what happens. Thanks for the idea.

EDIT: It didn't work... And I even ran 3 houses down just so that my eyes wouldn't cut out on me upon the flash, and so that I could see what color the little flash was. It was as white as ever :(

[DaveTheShit]

PVC is a chlorine doner, I know that much. However, I'd think the perchlorate would also act to donate chlorine to the reaction. Am I right, or am I making a fool of myself?

[THErAPIST]

You're correct David. I'm starting to think that Visser was color blind :p

[vulture]

Did you use it loose or pressed in a tube?

[THErAPIST]

I've tried it both in a polumna and in the open, both did pretty much the same thing. The only difference was the polumna make a nice bang and made a flash, and when it was jut lying in a pile on the ground I got a gusty woosh noise, and it lit the area up a little more.

I've been messing with the stuff all night... I actually just had my neighbor come outside and ask me "What are you doin this early in the morning? A flash of light just came in through my window and woke me up." to which I had to reply "Oh.. I'm really sorry. I'll quit messin around." He just laughed and said "Oh well" as he turned aropund to go back inside. Nice to know that atleast the neighbors dont mind...

I have added some sodium bicarb though and achieved a slightly more yellow flash. Now all I need is my red and the green that hates to exist :D

[yt2095]

I`ve read somewhere (perhaps even here) that Barium is used in white flash to counter the mild lilac color of the potassium.
perhaps you could substitute the KClO4 with BaClO4?
and use a copper salt for the Blue depth in the Green, perhaps a extremely tiny Sodium quantity could be added for adjustment.

all the best :)

[mr.evil]

try to use powdered magnesium instead of Dark Al. Green needs a very high temperature for his color frequency.

[yt2095]

Therapist,

i just quickly knocked up a small batch of green to test my idea.
in grams i cant tell you, sorry :( i use spatulas and spoons.
the Barium Perchlorate 50%
Mg and Cu (80/20) 40%
Cu2Cl 10%

i think i already had sodium contamination in my copper chloride because of the way i made it years ago.

results: a lovely green flash but lacked the deep Whuuump effect when piled in a crucible and lit.
you`ll have to adjust the mix yourself to your own liking. you`de probably need a thick walled tube to make a good report (in my esstimation).
this was only a quick mix off the top of my head i mixed up while waiting for my Ammonia to condense.
hope it helps :)

[THErAPIST]

Barium perchlorate? Hmmm... Aight. I appreciate it alot yt2095. Thanks. I shall have a try at it if I can get my hands on some magnesium :D

[kingspaz]

'perhaps you could substitute the KClO4 with BaClO4'

its Ba(ClO4)2. no point quoting a formula if it is wrong.

[yt2095]

good point!

my jar`s marked up BaCl2O8
i took a shortcut like that which is done Phospourus pentoxide writen up as P2O5 when infact it`s P4O10 as a molecule, i guess it`s the difference between O and O2.
your quite right tho, i cocked that part up either way you look at it! :(

thnx for spotting it :)

[Crazy Swede]

THErAPIST, the formula you mentioned will not work for three reasons:

1. Using Al as a fuel will not be effective since the combustion product, aluminium oxide, has such a high boiling point that it will exist as incandescent particles, emitting white light in the flame. Instead, Mg or MgAl must be used since MgO has a lower boiling point and will exist as a gas in the flame.

2. The formula lacks a chlorine donor. As a rule of thumb, any coloured metal fuel composition will require 15-20% chlorine donor to emit a good colour. There is a common misunderstanding that potassium perchlorate can act as a chlorine donor. The traces of free chlorine that can be detected when potassium perchlorate decomposes is not enough for coloured compositions. Organic chlorine donors, like dechlorane, hexachlorobenzene, PVC or pergut, or oxidizers that will give off free Cl or HCl, like potassium chlorate or ammonium perchlorate, are the only effective chlorine donors.

3. The level of barium is too low in your composition, I would advise at least 40% barium nitrate.

The use of coloured flash differs a bit from ordinary flash powders. Some compositions are more effective if lightly confined and will therefore only give mild puffs considering the sound level. Others need heavy confinement to work at all since the burning rate usually is a lot lower compared to ordinary flash powders.

Try these formulas, BUT, don't forget that magnesium/nitrate compositions can spontaneously ignite if moist! Keep everything dry, the strontium nitrate might have to be dried in an oven. To be on the safe side, about 3 additional percent of potassium dichromate should be added to inhibit the corrosion of the magnesium. (The chromate will also act as a catalyst and speed up the burning rate a bit!):

GREEN FLASH
8% Potassium perchlorate
42% Barium nitrate
25% Magnesium powder
17% Pergut or PVC

RED FLASH
5% Potassium perchlorate
50% Strontium nitrate
28% Magnesium powder
17% Pergut or PVC

[vulture]

2. The formula lacks a chlorine donor. As a rule of thumb, any coloured metal fuel composition will require 15-20% chlorine donor to emit a good colour. There is a common misunderstanding that potassium perchlorate can act as a chlorine donor. The traces of free chlorine that can be detected when potassium perchlorate decomposes is not enough for coloured compositions. Organic chlorine donors, like dechlorane, hexachlorobenzene, PVC or pergut, or oxidizers that will give off free Cl or HCl, like potassium chlorate or ammonium perchlorate, are the only effective chlorine donors.


KClO3 and KClO4 will act exactly the same as chlorine donor, as they both form KCl.

I'm sorry but I have to disagree on this one. Then strontiumcarbonate and potassiumchlorate wouldn't emit a deep red colour without chlorine donor and I use it all the time without chlorine donor.
70%KClO3/30%sugar and +5% SrCO3 emits a bright deep red light.
You don't need chlorine, you need chlorine ions. That's a big difference.


The problem is the weak color of barium itself. Because barium with chlorate gives a very weak color too.
Try the following mixture:

70%KClO3
15% dextrine
15% Mg
+5% Ba2+
+5% KCl

It's not usuable as a cracker comp, but very suitable for flares.

[knowledgehungry]

Can Copper sulfate KClO4 and Al be used for blue flash? I've got to get my red white and blue flash for the 4th.

EDIT: Yes i know that it burns green in flame tests but i had read somewhere that copper salts are used to make blue flash, if the copper wont work are there any other metal salts that will?

[vulture]

Copper works very well for a nice green flame, atleast coppernitrate in a bunsen flame does :D

[IPN]

knowledgehungry:

I don't know about the copper sulphate but I have used copper(II)oxide with great results!
Remember to add some chlorine donor to your mix to get better colors.

Oh and you should make your copper sulphate anhydrous if you are going to use it.

[kingspaz]

or make copper chloride. then you have the chlorine donor and copper in one. copper chloride can be made by mixing calcium chloride solution with copper sulphate solution. calcium sulphate will precipitate out leaving copper chloride in solution. then you just need to boil off some water and filter out any extra calcium sulphate that precipitates. then its just a case of evaporating the water.

edit: just remembered. blue flame can be had by using TACN i think. may be an interesting experiment.

[knowledgehungry]

Yeah, copper chloride would be best wouldn't it for blue? Can Copper chloride be made from reacting it with HCl? I know it doesnt at STP but maybe with acatalyst or with heat...?
I'll let you know how my copper sulfate goes in about an hour or so.
Edit: damn it kingspaz i need to start typing faster second time you beat me to replying!

[Crazy Swede]

Vulture, I'm afraid you've got it wrong. Free chloride ions is not at all effective as chlorine donors. Check whatever pyro book you want. For example Shimizu clearly states that free chlorine or chloric acid is essential to form the excited mono chlorides of barium, strontium and copper to produce high quality green, red and blue flames respectively. (Here I'm talking about high temperature compositions!)

You are also confusing the low temperature decomposition of potassium chlorate,

2KClO3 -> 2KCl + 3O2

with its, for pyrotechnics useful, side reaction that generates chlorine gas (check for example the middle of page 242 in Ellern's "Military and Civilian Pyrotechnics".) :

4KClO3 -> 2K2O + 2Cl2 + 5O2

This side reaction also excists for potassium perchlorate, but for some reason, unknown to me, to a much lesser extent and is therefore insufficient for producing coloured flames.

What you also must be aware of is that strontium hydroxide emits light in the red area of the visible spectrum. But this is a orange tinted red and not the blood red colour that we usually want.

It is true that the problem with green compositions to some extent is connected to the fact that excited barium monochloride emits some of its energy in the near IR part of the spectrum. But, the pure BaCl emission is strong and pure emerald green! The trouble we often run into is mostly connected to two things:

a) The green colour is very easily disturbed and becames washed out or yellowish from many contaminants, like sodium, calcium, strontium and copper. Dextrin is often a source of sodium, which might explain the weak colour of the composition you posted. Also, the amount of barium compound is way too low!

b) Similar to the excited CuCl molecue, the excited BaCl molecule is also temperature sensitive and the burning temperature of a green composition must therefore be lower compared to a red composition. Therefore, it is difficult to get the same light intensity and depht of color in green flash compositions compared to red ones.

Hope this explains it all! :)

[knowledgehungry]

So for Blue flash to work i need another chlorine donor such as PVC since the perchlorate isnt very effective as a chlorine donor?

[vulture]

I don't think a chlorine donor is needed for copper. I've had deep green/blue flames with just pure coppernitrate in a flame.

[Crazy Swede]

Knowledgehungry, it is right that you must add up to 20% of some chlorine donor to a blue composition. But, you will fail with blue flash as long as you base the composition on metal fuels. The only nearly suitable compositions I have worked with were based on ammonium perchlorate, copper oxychloride and phenolic resin.

As I stated in my post above, the burning temperature of blue compositions must be kept low, preferably below 2000 degrees Celsius. Adding anything above 5% Al or MgAl will ruin the colour!

Blue flash is the most challenging pyrotechnic effect there is! All attempts I have seen have always looked like white flashes with a weak blue tinted aura.

Since it is physically impossible to achieve as bright blue flames as reds or greens, one must focus on developing a composition that burns as deep blue as possible and then fire it alone or together with very dim effects such as kamuro or dark rain shells.

[Crazy Swede]

Vulture, I don't want to sound cocky, but what you THINK isn't relevant here, trust me!

What I have written is true and I can't see the point in doubting information from the most respected works in the industry (Shimizus "Fireworks, the art, science and practice" and Ellerns book mentioned above).

Maybe it's just that you don't have the experience yet to judge what counts for pure blue or pure green flames in pyrotechics?!

Of course you can get bluish or greenish flames without chlorine donors but thay will differ vastly from the ones with those substances.

[vulture]

Maybe you should use the edit button?

I'm sorry but I know what deep colors are. I lit my whole street in bright red light on New Years eve, it was as red as a stopsign. People from down the street came asking "What was that bright red light we saw?"

I do not dispute those sources. I just said that copper, unlike Ba or Sr, will already significantly color a flame without chlorine donor.

Furthermore, you can quote as much as you want, but have you made those compositions yourself?

The green colour is very easily disturbed and becames washed out or yellowish from many contaminants, like sodium, calcium, strontium and copper. Dextrin is often a source of sodium, which might explain the weak colour of the composition you posted. Also, the amount of barium compound is way too low!

I have not tried this composition nor did I say it gave a weak flame color. I did try the same variant with Strontium though and it was the most brightest red (NOT WHITE!) I've ever seen. I added the dextrine to slow down burn speed and thus lower the temperature and it obviously worked. So I was thinking that it could maybe work for Barium. That's all I was suggesting.

[Crazy Swede]

You have managed to produce a good red colour. Fine!
But, I can't see how that makes you experienced in viewing protechnic flames of other colours!?

You have proved that copper nitrate in a bunsen burner gives blue-greeninsh colour. OK!
But, that doesn't have anything to do with how copper behaves in a pyrotechnic flame!
Besides, I am talking about pure deep blue flames, not greenish-blue ones.

In pyrotechnics we only use the emission from the excited CuCl molecule to produce blue light. The formation of CuCl is a reversible reaction in the flame, so there has to be an excess of chlorine or chloric acid there to push the reaction in favor of high CuCl concentration.

You asked about which compositions I have tried. Well, I have tried all compositions I have mentioned in my posts. Or, did you mean if I've ivented them? Then the answer is no! About 15 years ago, I experimented with potassium chlorate/strontium carbonate/lactose/dextrin compositions. I liked their colour, some kind of pastel red flame, very nice indeed! So, I don't question that red formula of yours.

What I'm reacting on is that you don't seem to understand some of the basic fundamentals connected to the producing of good colours. But, I'm not blaming you for this!

[vulture]

In pyrotechnics we only use the emission from the excited CuCl molecule to produce blue light. The formation of CuCl is a reversible reaction in the flame, so there has to be an excess of chlorine or chloric acid there to push the reaction in favor of high CuCl concentration.

Odd. I would expect a higher chlorine concentration to favor the formation of CuCl2, no?

CuCl + Cl* <---> CuCl2

I assume the free chlorine is present as a radical?

[kingspaz]

Crazy Swede and vulture, enough of the bickering.

Crazy Swede, if vulture is wrong explian why properly instead of just dismissing his ideas and acting like you know it all. you may know alot but nobody ever knows it all. furthermore, if you think vulture doesn't understand instead of acting explaining small pieces of things explain IT ALL. then nobody has an excuse not to understand and we are all wiser as to why flames are coloured the way they are.

[THErAPIST]

I have made blue star formula by just dicking around...
http://i-was-bored.8m.com/fireworks/Mvc-003f.jpg
That was made with KClO4, sucrose, CuCl2, and BaNO32.. NO chlorine donor there besides the KClO4... This of course isn't flash, but deep blue flames DO exist without any special chlorine donor from what I've seen. The picture is pretty good, but the flame in all reality is a good bit more blue, it's just bright as shit so the camera didnt like it. That comp looks extremely blue when goin through the air too.

EDIT: I now not only think that visser was color blind... But I think he must have been slightly mongloidish too if that was HIS green formula I used :D

[vulture]

Nice! That's certainly is the sharpest blue in a flame I've ever seen!

NO chlorine donor there besides the KClO4...This of course isn't flash, but deep blue flames DO exist without any special chlorine donor from what I've seen.

Now that's an experimentally backed up result. Waiting for one from the Crazy Swede...

[THErAPIST]

Just tryin to help ya out alittle Vulture. :D

[Crazy Swede]

Kingspaz, ok I agree! I tend to get overly irritated on general lack of easily gained fundamentals and sometimes that shines through, obviously. Sorry!

But, on the other hand, I don't have the time or energy to really explain it all in depth. I advise you all to read Petri Pihkos article on http://cc.oulu.fi/~kempmp/colours.html that explains the fundamentals in a nice way.

However, to clear things up, regarding the discussions above, I will throw in a few more pieces of information. Most of the theory is ripped from Kosanke’s “Lecture notes for pyrotechnic chemistry”.

Potassium perchlorate can produce Cl* (chlorine radicals), but the reaction is not energetically preferred and the actual amount will be very small:

KClO4 + 2C -> KCl + 2CO2 + 1.4 kcal/g
4KClO4 + 2C -> 2K2O + 7CO2 + 4Cl* + 0,5 kcal/g

This explains why potassium perchlorate isn’t effective as a chlorine donor and therefore, it is more effective to add a separate chlorine donor, which usually also works as a secondary fuel.

When trying to formulate compositions for coloured flames there are several things that affect the colour quality. Many elements and molecules will emit light in the visible part of the spectrum but quite few of them are effective when it comes to produce flames of high colour purity. Most colour species are not stable chemicals under normal conditions. They cannot be used directly as colour agents and must be formed in the flame.

Regarding Vultures question, why a high chlorine radical concentration doesn’t favour the formation of cupric chloride, CuCl2, the answer is that CuCl2 decomposes at around 1000 degrees Celsius to form free chlorine and CuCl, which in turn only is stable up to about 2000 degrees Celsius.

Maybe you then ask why CuCl2 seldom is used as a colour agent? THErAPIST’s posted picture clearly shows that it can work, on an experimental level. The answer is that it is too hygroscopic to be of practical use. Instead cuprous chloride, CuCl, or copper oxychloride, ClCu2H3O3, is highly recommended.

Since blue is the most difficult colour, lets continue with copper as an example, even though the thread was about producing green light.

There are several emitting copper species in a flame but only two of them are desirable for the pyrotechnist. Below is a table of the most common emitting species, their emitted colour and their corresponding wave length:

CuOH -> green to yellow green (526 to 553 nm)
CuCl* -> blue-purple to purple-blue (403 to 456 nm)
(The * indicates radical species)
CuO -> red (? nm)

One might think that CuOH should be totally avoided. However, a small amount should act to improve the colour by shifting the color point from violet blue to blue with only little loss of purity.

As I said above, metal fuels should be avoided in blue compositions since a verly high burning temperature will destroy the blue emitting species. But, CuCl* is not only sensitive to high temperatures, but also to oxidation. This is the reason why many blue flames have a red tip if watched closely (CuCl* reacts with atmospheric oxygen under the formation of CuO). And this also tells you that your blue compositions must be a little fuel rich to optimise the formation of CuCl in the flame.

I don’t have more time at the moment, but I will gladly try to answer specific questions.
:)

[vulture]

Do you have data on the emission coefficients of those compounds and at which specific temperature those wavelengths will be emitted? I'm asking because I could calculate the wavelenght shift for any given temperature then.

BTW, CuO red? At which temperature? Because my coppernitrate experiment obviously produced CuO. :confused:

[Crazy Swede]

No, unfortunately I don't have any spectral handbooks with data for molecular band emission. But the bands I mentioned are the strongest ones!

If enough chlorine radicals are present in the flame, the dominating emitting species will be CuCl* as long as the temperature is below 2227 degrees Celsius. I'm not familiar with the lower temperature limit!

Regarding your Bunsen burner experiment, the flame colour you saw was not from CuO but from CuOH and other copper species. CuO has four bands from about 600->640 nm but the red emissions are very weak and not noteworthy, unless it's a sign of fuel deficiency!

By the way, the brilliant green sparks that can be seen from electric discharges between copper wires, the result of band emission from Cu2, is unfortunately not available for pyrotechnics!

[yt2095]

Therapist,
Beautiful blue mate!

i`m left wondering now, if you can use the same stuff with a few sodium ions in it make a green that`s just as deep?
maybe a sodium chlorate or just common house salt, you wouldn`t need alot i shouldn`t imagine.

sweet pic tho :)

[Crazy Swede]

yt2095, one might think that if mixing a blue burning composition with some sodium containing compound you would end up with a green flame, since that's the way blending ordinary colours work.

When it comes to light emission however, the results from mixing different colour emitting species is a bit different and is most easily explained by the chromaticity diagram. Check it out at:

http://cc.oulu.fi/~kempmp/chrotrue.jpg

In the diagram, you draw a straight line from blue to yellow. The resulting flame colour from mixing in sodium in a blue composition will be somewhere along this line, depending on how much emitting sodium atoms there are in the flame compared to CuCl radicals.

In theory, exactly the same approach can be used to predict the colour result from any other blend of emitting species. In practice, you often end up with much more washed out colours since it is almost impossible to produce as pure colours as the diagram predict.

[yt2095]

and so, if i`m to understand you and that diagram correctly.
Na ions in his Blue, would at best become white? or lilac (witout excess Na doping).
yes your quite right, it is VERY contra-intuitive indeed!

i`ll take your word for it , for now (no, NOT calling you a liar at all!) i`de just like to try and see it for myself with my own chems and eyes :)

i can PARTLY understand what your saying though, it`s a bit like adjusting the RGB guns on a TV tube.

thnx for the diagram, i`ve seen it several times before, but until you explained about the ruler idea, i just dismissed it (i`ve saved this one for printout now) :)

Cheerz`n`Beers :)

[Crazy Swede]

Ahhh...
Finally a person that understands and appreciates what I’ve written.
Thank You, yt2095 !

You are right that adding sodium to a blue composition will gradually wash it out until white, then, if more sodium is added, the colour will turn into yellow. Actually, adding small amounts of barium and/or copper compounds to yellow sodium based compositions is a common way to alter the ordinary “boring” yellow into more appealing shades like lemon yellow or canary yellow. Those altered yellows tend to blend very nice with green, purple and blue effects. (Ordinary sodium yellow looks dirty together with pure blue and deep green, at least in my opinion!)

Another thing, I wrote all my posts above in a hurry and it’s not until now that I realise that I’ve been writing “chloric acid” all the time, when I actually meant hydrochloric acid. Sorry for that!

[kingspaz]

Crazy Swede, i'm sure other people appreciate the information aswell but are less keen to thank you given your posting style towards the beginning of the thread.

[Crazy Swede]

Point taken, Kingspaz!

I noticed another error in my discussions above, regarding the dissociation temperature of the light emitting species.

It is the green emitting species BaCl* (the excited state of gaseous barium monochloride) that is unstable at temperatures above 2000 oC. So, to get a real good green flash, it's probably best not to use more than 5-20% Mg, depending on how much of secondary fuels or cooling additives you have in your formula.

The CuCl* (the excited state of gaseous copper monochloride) will start to dissociate already at temperatures as low as 1200 oC! But, to optimise the blue flame, it is often necessary to sacrifice some colour depth in favour of its brightness. Otherwise, it will be impractically dim. This means that it sometimes can be effective to adjust the burning temperature up a little, even though you might loose some depht of colour!

[yt2095]

i don`t take sides anyway :)
the explaination as to how to use that seemingly ubiquitous color diag was however gratefully received (to be honest i suspect it was just laziness on my part not to find out myself).

i`ve read above about chlorine donors, i beleive i understand it a little. it got me to considering OTHER donors.
could Ammonia be used as potential donor? don`t ask me how, it`s just a GUT feeling (not very scientific i know)
it started as i got to thinking about PVC as a chlorine donor, and could something inorganic be used to same effect.. from there my mental trail lead to thinking of OTHER donors for different effects/enhancement for different compounds.
i`m an experimentalist and rarely to never a "Sheeple" as NBK puts it.
the forums in the mode of free thinking and experimentation anyway, i wondered if any of you could point me in the right direction at all. i`m sure not everything`s been discovered yet! :)

all the best :)

[knowledgehungry]

Not being very knowledgeable on pyrotechnics im not sure what effects other donors would have. But it is always nice to see someone who is curious and wants to attempt new things, not just find better ways to make AP.

[Crazy Swede]

I agree with you that everything's certainly not discovered yet. I would encourage anyone to do experiments to convince oneself of something, or trying to prove that someone else is wrong. But, I don’t believe in stubbornly look at stones that someone else already turned!

Lets take the basics:
To produce light, we must add energy to a system. In pyrotechnics, we use heat from the combustion. When energy is added to atoms and molecules, their outer electrons will be excited, which means that they will jump up to higher energy levels. When the electrons fall back again, energy will be emitted in the shape of photons. The frequency of those photons can be seen as a fingerprint of a specific atom or molecule. If the frequency falls inside the visible part of the spectrum, we will experience this as white or coloured light.

To predict what species could be effective for light production, you have to know the possible electron energy levels for a specific molecule or atom. Those can be calculated, but as I remember, that was the most boring thing I’ve ever done during my years at the University :p

I don’t personally own any spectral handbooks, but I’ve spent many hours reading them (and trying to understand them :o ). The conclusion I draw, which also is backed up by the existing literature, is that it is only the excited mono halides (fluorine, chlorine, bromine and iodine) of copper, barium and strontium that are really effective at emitting blue, green and red light respectively. So far, I haven’t seen a single nitrogen containing species that would work.

There exists some other possible candidates for coloured light production, but they always seem to be too expensive, hygroscopic, reactive or poisonous.

However, who knows, maybe YOU will found the Columbi egg! J

[Mr Cool]

Polyatomic donors would probably break down at the high temperatures inside the flame, for example ammonia would produce nitrogen and hydrogen.
Maybe you could use halides of transition metals (in high oxidation states), for example FeCl3 which could break down to produce FeCl2 and free chlorine?

[yt2095]

Indeed!

FeCl3 would be a great idea! and probably other such chems of that ilk, this i what i wish to look into at a greater depth :)

Crazt Swede, sure, i understand about 1`st, 2`nd , 3`rd ionisation energies, i studied that during my Laser project at college.
tho i`m into Pyro and have been since age forever! i was curious as to what the dynamics were with these energies in respect of heat and chemistry.
Lasers are a little different (tho similar in some ways) esp, laser ablation in spectography.
pyro on the other hand is somewhat a different kettle of fish, many more factors to taken into acount, compensated and adjusted for :)
i`m more than possitive that i`ll be turning over a good many stones previously looked at by others, in the same way that i thought i was "well excellent" when i discovered TATP all by myself many years ago (22 years ago to be exact) and didn`t even know what it was ( i was lucky as i considered it new form of gunpowder and never had any accidents) that`s why now i continue my AP experiments where i left off. as well as newer things.
anyway, this is turning into a boring text i`m sure.
if you take nothing else from this tho, try to veiw things as a child might, with wonder and awe, curiosity is the best educator :)
spoon fed Dogma and predigested ideas, are`nt my way.
thnx for comments, any more on Donors would be great too! :)

[blindreeper]

I'm not sure if this is helpful, but I have seen this before and when you guys are having your discussion I thought of this:

http://www.webelements.com/webelements/elements/text/Cu/key.html

It has some stuff about cool flames and colours emitted from copper salts (brief though)

[yt2095]

short but sweet :)

now i simply must make some copper(1) chloride!

i particulary like that little bit at the bottom about the Anode slime, as precious metal extraction is another hobby of mine also :)

thnx Blindreeper.

[blindreeper]

No worries, but CuCl is hard to make without Na ion impurities no? Perhaps recrystalization? I'm also not to sure on the discusion about chlorine donors and that kind of field but I did read above that KClO3 can provide the neccessary chlorine to give the deep rich colour desired. And on that note has anyone noticed that the burning mix was KClO3/sugar and the cuprous chloride and judging by the colour flame in the picture it seems to work. Perhaps the KClO3/sugar mixture could be used to test your copper chloride for impurities (Na ions)

[yt2095]

perhaps with electrolysis of pure HCL(aq)? it`ll elliminate the Na ions. and should leave a fairly recognisable sollution, tho i have noted in the past that when it`s crystalised, if you go beyond the ?.H2O water of crystalisation it goes a yellow brown color indicative of CuCl2?
i`ll have to examine a few crystals under my microscope before that stage and look for cubic crystals.
either way, it should certainly be a good cupper salt and chlorine donor. i used all my original copper chloride in the test i did a few posts ago. it was a bit contaminated and old anyway, and i didn`t have any HCL(aq) back then. maybe i`ll get a better batch this time :)
it`s certainly provided an incentive!

as for the KClO3/sugar, it certainly seems to be a good neutral benchmark deflagrant for color testing! i think i`ll whip up a bag of that too while i`m at it. something to do on a rainy day :)

[Crazy Swede]

I have, again, noticed an error. This time in my very first post in this thread :o

When I mentioned that Al is inferior to Mg, when it comes to producing coloured flames, I erroneously said that the boiling point of MgO is lower than Al2O3. The boiling point of Al2O3 is 2980 oC and the boiling point of MgO is 3600 oC!

So, then you ask yourself "But why the fudge did you tell us that Mg is better then?"

Well, if there's a source of chlorine in the flame, the magnesium oxide will react to form magnesium chloride, which has a much lower boiling point, 1412 oC, and Voila! You have a transparent flame with a minimized amount of continuous radiation (white light).

The same reaction does not occur for aluminium oxide, which explains, in terms of colour purity, why Mg is a better fuel than Al.

This also explains why it’s so necessary to have an excess of chlorine containing compounds in a composition based on metal fuels. In such compositions, below 15% of chlorine donors will seldom be effective.

[yt2095]

i`ve read somewhere that a way to obtain Mg powder would be to electrolise MgSO4 using Mg electrodes.
to me this just seemed like a good way to make MgO at best.
i may be wrong tho, but i should imagine that the heat generated in the reaction would just make Mg hydroxide of any Mg that may temporarily form, liberating Hydrogen.
any ideas?

[knowledgehungry]

I made a light blue flash like composition using Al, KClO4, hexamine, sucrose and CuSO4 it burned a little slow however, but then again my KClO4 wasnt powdered very well.

[IPN]

I tried to make some sort of flash powder with PbO4 and Zn in 70/30 ratio (I don't have chlorates or Al powder :( ).
The results were quite boring, I didn’t get good sound with it but the color is nice though.
Anyways here are links to the films I took (thanks to Axt they are now .mpg)

http://koti.mbnet.fi/otto2000/Tests/PbO4_Zn.mpg
http://koti.mbnet.fi/otto2000/Tests/PbO4_Zn_2.mpg

Tomorrow I will test the same composition with some catalysts (TiO2, MnO2, V2O5 ect.)
Also a strong cardboard tube might give better results..

[knowledgehungry]

Was it just me or was the mixture giving off a greenish/blue light?

[Crazy Swede]

yt2095, you asked about electrolysis of magnesium sulphate. I agree with you, since the sulphate is an oxidiser, any formed magnesium will immediately be oxidised into magnesium oxide.

The industrial way of producing magnesium metal is to use dehydrated magnesium chloride. This is melted at 700 oC and electrolysed with iron cathodes and graphite anodes under 5-8 V. The magnesium is formed at the cathodes. (Taken from Shimizu)

Knowledgehungry, the blue-green colour is produced by elemental zinc. Pyrotechnists have in fact used compositions containing this metal since the eighteenth century! In those days, it was the only way of producing anything close to blue or green coloured light. Today, most people feel the effect is too dim. But, a good Electric Spreader Star can be very impressive! Unfortunately, the composition is quite dangerous to handle. Have a look at rec.pyrotechnics for more zinc composition information.

[knowledgehungry]

I recently discovered that i have some Cobalt Chloride. I read somewhere that Cobalt gives off blue light at high temparatures, and since it also is a chloride it might work very well for blue flash. Does anyone have any ideas on this? I was thinking of trying 80KClO4, 15 Al and 5 cobalt chloride.

[Sparky]

I can predict one reason why that cobalt chloride mix may not work. The aluminum oxide has a high boiling point which results in it giving off lots of black body radiation and so it will tend to wash out any color by making it whitish. Like Crazy Swede was talking about, you could try and use magnesium then a chlorine donor to convert the magnesium oxide to magnesium chloride. Then you don't have as much black body radiation to contaminate the flame.

Come to think of it a flash powder based on ammonium perchlorate and magnesium (protected with potassium dichromate I suppose) then a coloring agent like say strontium chloride could work for a red flash. Ammonium perchlorate is a good chlorine donor so that could take care of the magnesium then the strontium chloride could provide red under the high temperature (where as copper chloride blue would probably not work since the temperature is way too high).

[blindreeper]

IIRC cobalt coumponds give out a red colour, colbalt nitrate certainly gave a nice red comlour when in solution when we did a flame test for different ions :p

[yt2095]

I`ve succesfuly used LiNO3 in red stars (tho it is somewhat deliquescent).
i don`t have any access to strontium compounds, but had a load of Lithium batteries laying around in a box. carefull dismatling of these and dissolving the Li in water (use a plastic cup as LiOH reacts with glass), then adding the acid of your choice until the PH is neutral, then evaporate excess water and crystalise. i used nitric acid, but i`m sure HCL(aq) could be used also.
i`ve read on here that a good source of color ion compounds can be found at pottery glasing shops, i`ve yet to find a local one as of yet.
but Lithium is certainly worth a try also, tho i wouldn`t use it with a (per)Chlorate as nitrates and Chlorates are potentialy dangerous.

[Crazy Swede]

There was an interesting article in Journal of Pyrotechnics, issue 13/2001, called “Evaluation of Lithium Compounds as Color Agents for Pyrotechnic Flames”. The author, Ernst-Christian Koch, came to the conclusion that the principle emitter of red light in such flames is atomic lithium. His recommendations were to use fuels with high hydrogen content, make the compositions fuel rich and to avoid halogens. If halogens cannot be avoided, aluminium should be added to scavenge the halogen. The reason for the detrimental effect of chlorine is that almost all of the Li in the flame will be converted to LiCl, which emits most of its energy outside the visible region.

By the way, the chlorine scavenging effect of aluminium is another reason why the metal is not a suitable fuel for colour compositions!

[yt2095]

great :)

it would seem i made the right choice of acids afterall. and yet another good reason to avoid Chlorine.
an interesting effect of Li as opposed to other metals, is that as a nitrate it`s almost 100% recyclable. after the nitrate decomposes it leaves LiOH, the addition of nitric acid, gives you your LiNO3 again :)

it would seem that there is no ONE neutral composition for general color testing then. a pity really as KClO3 (4) and sugar seemed so promising. as i now have quite an amount of KClO3 and wished to move on to different compositions for stars and color flash. i`ve stuck to using Nitrates so far.

so Nitrates for Li, and Chlorates for others seems to be the order of the day so far :)

[Crazy Swede]

yt2095, you're right about that there might not be one singular pyrotechnic base composition that you could add different colouring additives to for evaluation. But, I have some tips to facilitate the screening of possible candidates:

1. Start with flame tests in both slightly oxidising and reducing flames. This is most easily achieved in a Bunsen burner where you can adjust the gas/air mixture. If you would like to use an alcohol lamp instead, you will not be able to produce an oxidising flame. Methanol will burn almost neutral and isopropanol will give a yellow, reducing, flame.

2. Try adding chlorine, in the form of ammonium chloride (salmiac) or hydrochloric acid to the potential additive, before performing flame tests as described above.

3. Depending on the results from above, you will get an idea of how you should manipulate a composition to produce an ideal flame environment for the colour additive of your choice.

[yt2095]

Slendid idea!

i expect that a simple candle could be used to good effect as a reducing flame also.
a blowtorch as oxidising (correctly calibrated of course)

i`ve been considering your idea about the introduction of chlorine gas to the mix.

in a bunsen arrangement (fairly simple to make from a blowtorch some solder and spare copper pipe bits) that a secondary inlet could be introduced into such an arangement, for things like Chlorine or other gasses, and if correctly positioned and angled, pressurised gas maynot even be needed! as a suction effect can be produced :) (similar effect as that employed in an airbrush)

thnx for the idea, i`ll get to work on that asap, and maybe start building within the next week or 2 :)

be sure, i shall post my results :)

[knowledgehungry]

Well I am going to flame test my cobalt chloride just to see for myself, I'll let you know my results. Also i was wondering what effects flourine would have on compositions, I know that this thread is rapidly getting off topic.

[yt2095]

unless you have life insurance a fume cuboard or a death wish, i`de steer well clear of Flourine and it`s compounds, it`s also a contact poison!

please please please be MEGA carefull!!!! messing with it, i`ve lost a friend as a direct result of messing with HFl(aq)

to answer tho, i`de expect it would be similar to Chlorine only more violent and color vivid.

certainly NOT worth finding out without the proper lab kit!

Be happy, Stay safe!

[IPN]

Still no luck with the PbO4/Zn :(
I filled a cardboard tube half full of the 70/30 mix with 5% V2O5 added (one endcap was glued previously) and made the second endcap to it, allowed to dry for two days and here is the result:

http://koti.mbnet.fi/otto2000/Tests/PbO4_Zn_3_by_IPN.mpg

The endcaps didn't work. But I'm not giving up, all I need is better glue..

I also got some KMnO4 again and made some flash with it. 3/2/1 KMnO4/Zn/S gave this kind of results:

http://koti.mbnet.fi/otto2000/Tests/KMnO4_Flash_by_IPN.mpg

Now that was a decent flash :) (Just wait when I get some Al or Mg powder :D )

[Guerilla]

Hey nice clips IPN :)

That PbO4 comp looks rather nice. It obviously has some potent even though it didnt give the desired bang. ;) The oxidiser seems to cover pretty well the greenish flame that usually exists with Zn mixes - if I´m seeing it right from the video. I gotta place an order for the oxide some day.. BTW was the PbO4 red or black in color?

I´m too waiting to get my hands on the Mg powder, I better put the cell running for the rest of the summer so that I´ll have enough chlorate/perchlorate ready for flashes.. :cool:

[mr.evil]

Therapist,

Do you know your exact ratio's of your (great) blue color composition? 'Cause i can't get it blue, only white-greenish.

thanks :)

[Marvin]

Green means too little chlorine, or I suspect in this case, the flame is too hot. CuCl the blue emitter breaks down in high temperature flames. Blue burning comps are frequently carbohydrate based to keep the flame temperature fairly low.

I wonder if a decent blue flash is even possible.

Crazy Swede gives the cut off for blue at 2227C, that sounds massivly higher than I was expecting.

[knowledgehungry]

Maybe he meant 2227F.

[Crazy Swede]

The correct temperature, where the CuCl molecule starts to decompose, is around 1200 degrees Celsius.

But, since the intensity of the light depends on the temperature in the flame, it is difficult to say what is the ideal temperature for a given composition. The purer the flame is, the higher the temperature can be without sacrificing too much in colour depth. If the ingredients has lots of contaminants, such as Na and Ca, or if the combustion is non-ideal and produces soot or other particles, the colour depth will already be quite low and will soon be washed out at higher temperatures. This means that most compositions work best at temperatures below 1200 degrees Celsius!

[densest]

Some recent research suggests that the blue emitter in copper blue pyro is Cu4Cl4 (approximately). Copper and chlorine can form long molecules easily - that's why copper chloride/oxychloride salts are many different colors and never react the same twice. The polycopper-polychlorine molecules are even less stable than CuCl.<p>Skylighter briefly sold CuF2 powder which I believe gives the easiest and deepest blue with very little other halogen donor. I haven't tried it with any metals because organic fuels and perchlorate are accelearated by the Cu to quite a high temperature.<p>See also Hiskey's patents for low carbon pyrotechnic compositions - if only one could get guanidine nitrate in any quantity!!!<p>The alkali metals (Li, K, probably Rb etc.) work brilliantly if all halogen is excluded, and Hiskey's compositions are very good for that.<p>I apologize that I don't have a reference for the Cu4Cl4 item handy.

[THErAPIST]

Holy shit Mr.evil, I recently had the cops come to my house for a firecracker i set off in the road infront of my house so I havent really looked at much on this forum besides the watercooler since because i'd feel too strong an urge to go make somehting after I got done reading... But i'll go make some of the comp right now and measure how much of each thing is used for you. Again sorry for not replying till now

EDIT: OK i just made a batch and tested it.
You must remember that my scale isnt EXACT because its just a water bubble level used in construction suspended from a string that has two paper pouches, one on each side. I use nails for weight, and each one weighs pretty closely to a gram. I've never had a problem with weighing out specific amounts before so i guess its accurate enough.

3.5g potassium nitrate
3g sugar
3g copper chloride (think thats what it is)
and 2g barium nitrate

if youre doing parts, if everything is as fine as baking flour you would have:
4 parts potassium perchlorate
4 parts sugar
3 parts copper chloride
and 1 part barium nitrate

This time there were white pearls left after the pile had burned away so I imagine going down a tad with the potassium perchlorate might be fine. Going down to 3g with the potassium perchlorate should make it fine.

When the composition burns a brownish black residue is left behind. It goes out if strong wind hits is so mixing it with some BP would most likely improve performance slightly. If you were to do something crazy like put in about 1/3 of a gram of pvc (without taking away the .5g KCLO4) the blue might be a little bit more crisp but I personally don't think it's needed.

I hope I helped you out a little.

[mr.evil]

thank you very much Therapist!!!

school has started again, but soon as i have time i will try the composition and post some results :)

[Crazy Swede]

Densest, is it possible for you to find the reference that was missing above?

Do you know if the molecule actually has any influence on the emitted light from a pyrotechnic flame, or is its prescence only noted in other applications?

[densest]

to Crazy Swede - I'm sorry I can't find the references for polycopper-polychlorine molecules as flame emitters
My junk-pile memory didn't hold the author's name.
It was in some amateur or semiprofessional pyro publication from the US in the last 2 years - big help, sorry! The author was an academic with serious credentials in the business.

[Crazy Swede]

I would like to add some information I just received regarding why KCl doesn’t work that well as a chlorine donor in blue flames. (I could have posted this in the Flame Color thread, but all my previous comments regarding the subject were posted here before!)

What I got was a diagram showing a thermodynamic calculation of at what temperature KCl gas, in the form of (KCl)2, dissociates into free potassium and chlorine gas respectively. See link below:

http://www.imagestation.com/album/?id=4288439855

In the diagram, it is shown that the KCl gas starts to brake down first at about 1320 degrees Celsius

As we all know, successful blue flames must have a temperature below 1200 degrees Celsius since the blue emitting species, the excited CuCl molecule, will start to decompose around that temperature.

So, the theoretical conclusion is that KCl can’t be used as a chlorine donor in blue flames, since the effective flame temperature is lower than the temperature needed for the production of free chlorine!

[The Anarch]

If this offers any help at all, I have found in my experience that strontium nitrate and magnesium flake makes a nice red flash, while SrNO3 and powdered aluminum just produces a blinding white spark fountain. A friend of mine was also having some trouble getting a mixture of aluminum powder, potassium perchlorate, and copper carbonate to flash blue. I'm guessing that aluminum just isn't cut out for colored flashes. If you had any access to Mg you could just use that with the Ba(NO3)2 straight.

[vulture]

I was wondering how other halogens effect the color of the usual "color salts"?

For example what would CuF2 or SrF2 do in a typical pyrotechnic flame?

[Bert]

Yes, other halogens do work. Flourine is a lot more expensive than Chlorine though.

[vulture]

So, if one were to use SrF2 in a flare, one would still get a nice red flame?

I'm asking because SrCl2 is damn hygroscopic, like all other group IIa chlorides.
The fluorides are insoluble, so that might be an advantage.

[krimmie]

Wouldn't the high melting point of strontium fluoride (1460 C) be a disadvantage here? That's pretty high when compared with strontium nitrate (570C) or even potassium fluoride (860 C).

[vulture]

The only relevant comparison here would be the boiling point of SrCl2 vs that of SrF2.

[T_Pyro]

If the fluorides are insoluble, or at least less hygroscopic than the chlorides, and if they can provide the same effect as the "standard" chlorides, they would be of some use, but aren't fluorides extremely toxic? Sodium fluoride is indeed poisonous, but regarding strontium fluoride, as the MSDS puts it, "The toxicological properties of this material have not been fully investigated." That would be a major drawback to its usage in (amateur) pyrotechnic composittions, I think.

[vulture]

SrF2 is insoluble and thus cannot be toxic, just as CaF2. In fact, BaF2 would be MUCH less toxic than BaCl2 because of it's insolubility.

[Bert]

There's this issue with pyrotechnic chemicals, especially in non-military uses. The market is so small, commercial sources of chemicals don't care to cater to it. Hence, Pyrotechnists seldom ascertain the very best product for an effect and then go have it made. Instead, we find something that's allready made for another (larger) industry and adapt it to our needs. Chlorinated organics from the chemical, plastics and coating industries are cheap and widely available. They've taken over the Chlorine donor roll in compositions for this reason. Inorganic Fluorine compounds may work. They may even provide superior results in some cases. But they're not likely to do so in a cost competitive fashion. The Fluorine compounds I've seen used were all for blue star formulations, and I haven't seen them offered for a while. Have you considered adding Teflon powder to a high temp Magnesium fueled mix instead of Parlon or Saran? It could function both as an oxidizer and a halogen donor, perhaps.