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First ever homemade firework


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#16 Peret

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Posted 31 December 2010 - 10:42 PM

The questions I have are (oh I wish I was a chemist), why was the Titanium and magnalium tube so much more powerful and longerlasting than the aluminium one, and in the same instance why was the one that was strontium and antimony so much weaker, but twice as long.... I found it VERY interesting and informative, but now need to know the why's...


Well it isn't rocket science - oh, wait a minute.... :lol:

So, the one that was weaker took twice as long. That means it burned at half the speed, producing only half the gas per second, which accounts for the weakness. The actual question, then, is why it burned slower, not why it was weaker. And to answer that I would suspect it has something to do with the oxidizer (strontium nitrate), which is hygroscopic, and the weather. The fuel also plays a part because, other things being equal, the gerb that burns hottest will be most powerful, and your finely divided titanium and magnalium will be a lot more reactive and hotter burning than some oily aluminium turnings that probably wouldn't pass a 10 mesh sieve.

#17 knackers

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Posted 01 January 2011 - 11:24 AM

the mesh size of your MgAl is all important for crackling, if anyone has any test results for the grades please make youself known.


Hi phill, i cannot post results for multiple grades but can post results for the 100--200# size MgAl using the following formula, from pyro guide. Btw, my tube was a little long as this was a test for christmas, it was 200mm long but got a bit of build up towards the end......

'Dragon eggs' star (Crackling star)
Source: rec.pyrotechnics. Composition from "The best of AFN III"[12], page 121
Comments: Sometimes, Bi2O3 is used instead of Pb3O4. The composition is extremely sensitive, both to friction and impact. It is also quite poisonous and explosive. Gloves and an air mask must be worn at all times when handling this mixture since the mixture contains the very toxic Pb3O4.
Preparation: Add lacquer untill the thickness is like wood putty. Pass the mix through a screen and dry it to make 1mm squares. These will explode with a sharp crack shortly after lighting and can be used as star cores.

Pb3O4.............................................81.8
Magnalium (50/50, 100-200 Mesh)...................9.1
Copper(II)oxide...................................9.1
Nitrocellulose lacquer binder.....................10% by volume

crackling fountain

#18 dr thrust

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Posted 02 January 2011 - 10:51 AM

nice one phil, but doe's anybody know why or what? makes dragon eggs so sensitive?




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