12 replies to this topic

[Givat]

Name of composition: givat Green Star

Composition type: colored star
Composition:

Barium nitrate - 52
Potassium chlorate - 8
barium carbonate - 5
magnesium powder (don't know what mesh I got) - 15
PVC - 20
Dextrine - +8%

The star burn with the best green I ever seen, not washed out like most of the colored green stars.
The star is a little crumbly, one can try using different binder other then dextrine.


A 5 m"m star burning

[Pretty green flame]

Hmm i see 2 potential hazards here. Firstly: Potassium chlorate and a pretty reactive metal powder, doesn't sound right. And magnesium with a water soluble binder. I would drop the dextrin and bind the star with the PVC which is already in the formula. Magnesium and water don't exactly like each other especially if fine mesh mag is used. Or maybe NC lacq. is another option, bottom line is that i would avoid water soluble binders.

[Givat]

I'm using dichromate coated magnesium to avoid the reactivity of it.
using water in magnesium mixtures never gave me any warming, and of course not autoignition.
As far as I know this composition is very safe.

about the PVC as binder - this maybe can be very good idea. I will try this today and see oh it works. MEK is preferred or acetone can be used too?

.......................

EDIT: thanks for the idea PGF, I tried using acetone as the solvent in my star formula without the dextrine. Now the stars are less crumbly and they are a little elastic.
I'll try to find a sprayer which won't disolve in acetone, and will try to roll a batch of my stars.

[JamesH]

That composition has the potential for spontaneous combustion. Any combination of a nitrate, metal and a chlorate is very unsafe, especially in a damp state. Basically, this is because the metal will partially decompose the nitrate, releasing ammonia gas. The ammonia has the potential to react with the chlorate compound to give ammonium chlorate, which is a very unstable explosive compound.
There are two articles in The best of AFN II on this subject, one titled 'DEATHMIX' and the other 'POTENTIAL DEATHMIXES'. These can be found on pages 175-177.

The composition would be far safer if you substituted perchlorate for the chlorate.

Please everyone take heed of the warnings, I don't want to see anyone getting hurt as a result of mixing such a composition.

Stay safe,

James

[hst45]

Givat, I've had good luck using parlon bound with MEK to harden compounds which otherwise yield crumbly stars. I'm not sure if it's as good a chlorine donor as PVC, but you might try replacing 5% (of the total volume of the compound) of PVC with 5% parlon. I beleive that for this use acetone and MEK are interchangable, I just have always used MEK.

As far as the instability of this compound, I've always defered to safety as PGF and JamesH said. I've use perchlorate exclusively for metal fueled stars. Gutless, but safe. Let us know how these changes go; I love a really GREEN star. i've been out of barium nitrate forever, and the barium carbonate stars I've been making are really pastel/washed out. Good luck!

[Givat]

James, I read the pages you told me in the AFN 2, this potential spontaneous combustion is only when the composition is drying (as far as I understood), so if I will use acetone I will be safe. no?

As for the chlorate problem, I can't put my hands on any perchlorate in here so I will have to stay with the chlorate.
with out the chlorate all my green stars where very hard to ignite and needed 3 layers of prime.

Thanks for the warnings, But i will use PGF idea and will use acetone as a binder - so no water involved. I will also keep the ready stars separately from all my other pyro things, away from combustible things. Just to be safer.

By the way, I filmed the stars and post a picture of its burning in the first post, it was great as a flare too.

[JamesH]

All acetone, unless stated anhydrous, contains a small percentage of water. However, it is possible to dry the acetone using chemicals like calcium chloride, magnesium sulphate etc.
Acetone also causes condensation of water from the atmosphere during evapouration, so even if you dry the acetone beforehand you will still have water present at some stage. It would be a very small water contamination, but it still has the possibility of causing adverse reactions in the comp.
There is a lot of discussion on these issues on rec.pyrotechnics.

MEK would be a better solvent in this regard, althought i am not condoning the use of the comp mentioned in this thread.
Parlon would also be the better binder/chlorine donor due to its higher percentage of chlorine and its superior metal protecting properties compared to PVC.

Givat, the comp does seem to burn with a nice green colour judging by the photo, but I would be cautious of comp due to its questionable stability. You have proved that it works, but I would not personally put it any further practical use. Its always better to be safe (that is, as safe as pyro can be) than sorry.

I am sorry if it sounds like a lecture and I am in no way trying to detract from your achievements, but its really important that your aware of any issues that may arrise in this hobby, after all thats what this forum is for.

The magnesium is not vital to obtain a decent green, there are many organic greens that are based on barium nitrate, potassium chlorate, red gum and a chlorine donor. I would personally go that route if potassium perchlorate is not available to you. Also it would be cheaper due to the absence of magnesium.

Good luck to you in your pyrotechnic experiments, all the best!

James

[markx]

WOW..... just tried the mixture with slightly modified components. Instead of PVC I bound it with chloroprene dissolved in acetone-xylene mixture (Kestopren contact glue actually, but it makes no difference really).

The components were:

Barium nitrate - 52
Potassium chlorate - 8
barium carbonate - 5
aluminum powder (atomized) - 15
Chloroprene (dissolved)- 20


Man that's a perfect ten for a metal based green in my eyes Blinding saturated green with excatly the shade that I desired . I've been working towards that shade of green for so long and now I finally found it. Thank you so much for posting that mix here

[aa92td]

I have been made givat green stars , and just lighted one of them, amaizing beautiful green , blind me for 2 secounds and they are not so expensive.
soo givat nice compesition.

(sory about my English)

[aa92td]

damn, sorry about the double post.
its very hard to ignite those stars , the should have a huge prime!
but my problem is....WHAT PRIME?

i cant use black powder because the sensetivity of chlorate and sulfur.
i cant use any thing with sulfur or sugar.

so, any suggestions ?

[Mumbles]

Veline super prime should do the trick. H3 as a prime is another possibility, perhaps with some step priming or addition of metals. There are other primes based on perc that should work quite well. If you don't have perc, you are likely out of luck for these stars.

[hashashan]

I think that a good choise would be H3 with some MnO2 or dichromate added to it.

[Givat]

1 Idea, 1 question:

* On passfire it said there is no reaction of Mg with oxidizers other then AP if one use Mg coated with linseed oil.
So I guess my stars can be made with coated Mg and I will be safe?

* If linseed oil works so good, so my stars will have a good shelf life too, the Mg won't react with the chlorate/nitrate oxidizer. Am I right?


givat.