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Crackling Stars


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#31 Steve

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Posted 19 January 2004 - 04:44 PM

No far better than that, that is just a thermite reaction. From Lancaster pg 151. One of Shimizu's (I think)

KNO3 - 50.0
Pine Charcoal - 6.9
Sulphur - 20.0
Atomized Aluminium -17.3
Fe2O3 - 5.8

Technically the mix was designed as a glitter mix. I used willow or Charcoal (can't remember) and used 300# Aluminium to get the effect of crackles.

It is noted that boric acid destroys the glitter effect so if you plan to get this wet (to make stars, for example) you will have to put some thought into it, Damned if i can't be bothered to do it for you. :rolleyes:

Yes, there is a copper oxide mix.

Magnallium - 15
Copper(ii) oxide (black) - 10
Bismuth(iii) oxide - 75

Probably not what you were hoping for, but thats the only formula i can find that relates copper oxide to crackling stars, you might find that pure copper oxide is too reactive.

Steve
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#32 Matt

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Posted 20 January 2004 - 02:58 AM

I think youll find that copper oxide is used in every crackling star compo. Seems to play anh important roll...

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#33 bernie

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Posted 27 January 2004 - 01:32 AM

From Pyrotechnica XIV

Bismuth subnitrate__________70
Magnalium(50:50,-60 mesh___20
Copper(II) oxide____________10

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#34 Steve

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Posted 28 January 2004 - 10:40 AM

I think youll find that copper oxide is used in every crackling star compo. Seems to play anh important roll...

-Matt

Not all, there is one based on lead dioxide and magnallium only.
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#35 BigG

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Posted 28 January 2004 - 11:10 AM

Not all, there is one based on lead dioxide and magnallium only.

I know the one you mean. Lancaster posts Magnalium 11 and Lead Oxide 89. In reality, there are many formulation that do not require copper salts at all.

#36 BurlHorse

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Posted 28 January 2004 - 03:35 PM

I Just Ordered a pound of this, I'll get back to you on the formula mentioned in the above post, but judging from all the free O2 available from this formula, I'm going to bet that it will be relatively shock sensitive......


Safety data for bismuth subnitrate

--------------------------------------------------------------------------------

General
Synonyms: bismuth nitrate basic
Molecular formula: Bi5O(OH)9 (NO3)4
CAS No: 1304-85-4
EC No:
Physical data
Appearance: dense microcrystalline powder
Melting point:
Boiling point:
Vapour density:
Vapour pressure:
Density (g cm-3): 4.93
Flash point:
Explosion limits:
Autoignition temperature:
Water solubility: negligible

Stability
Strong oxidizer - contact with combustible material may lead to fire. Incompatible with reducing agents, organic materials. Toxicology
Skin, eye and respiratory irritant.

Regards, Stay Green

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#37 bernie

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Posted 29 January 2004 - 12:31 AM

In P XIV the author uses the subnitrate (what was at hand) version only in the development of lead free based dragon eggs. The author also evaluates the performance of different bismuth III oxide formulations. Some have multiple bangs, some have just one.

No doubt there are endless varieties. I think that when it comes right down to it ease of manufacture and safety will always play the biggest parts.

#38 BurlHorse

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Posted 29 January 2004 - 08:22 AM

Agreed Bernie !! :)
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#39 StfuStuf

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Posted 03 February 2004 - 04:08 AM

I have recently made some type of crackling stars... I dont know how they crackle but using flash powder and a lot of really coarse aluminum and coarse magnesium I have managed to create small crackling stars. I think it was like
Aluminum Coarse: 30
Magnesium Coarse: 10
Flash Powder: 60
Dextrin +10%
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#40 adamw

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Posted 15 February 2004 - 11:55 AM

You may find that the crackle produced by those stars seems reasonable at close distance, but weak in comparison to a true crackle formula. MgAl and even coarse Mg and Al on their own crackle or 'Sizzle'. However, what you have found may be suitable for your use.
75 : 15: 10... Enough said!

#41 dfk

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Posted 20 February 2004 - 06:43 PM

I went to a local pottery supllies store and was pretty much laughing to myself at amount of available supplies and low cost. I only left with some sodium silicate(I got a gallon for 8$) as I wanted to look into these chemicals uses for pottery as well as purity befor I stocked up.

My question is, they had red lead oxide(Pb304) their but it said that it had lead monoxide mixed in. Will this work in a dragon egg comp?

Edited by dfk, 21 February 2004 - 01:50 AM.

Marcus; 'In the practice of manipulating fire for 4 years'

#42 BurlHorse

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Posted 21 February 2004 - 09:40 PM

Trioxide, monoxide, whats a molocule betwwen friends haha, it will probably be fine, just start with small batchs so as not to waste chems on stuff that won't work.

Regards, Stay Green, BTW Where's everyone been, no new posts in 2 days?

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#43 Stuart

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Posted 21 February 2004 - 10:46 PM

There have been new ones in the past 2 days. The post before yours was made yesterday (20th)

Stuart

#44 The_Djinn

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Posted 22 February 2004 - 09:12 AM

There has been a dip in the posts, maybe some of the younger members are on holiday as it is mid term break and us older members are suffering from brain drain trying to keep pace with the youth of today :P
Or possibly everyone is out chopping down small forests getting ready for an orgy of charcoal making in the summer months :D
and it is to dam chilly to be outside dancing around the ball mill while chanting to the BP spirits to let your BP be the best there is to be had.

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#45 dfk

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Posted 11 March 2004 - 11:44 PM

This comp is amazing to say the least.

Mixing it was wild, I haven't done anything that exhilarating in a while.
Between dealing with its sensitivity and making sure none got on or in me the whole process took at least two hours.
I tried two comps, the first was definitely inferior
so I settled with this:

Pb304 70
Black CuO 12.5
Mg/Al 17.5
Al 200m(atom +5

The first batch I tried was screened and was rather week. After switching to the above comp I also switched to cutting. The end product was cubes that ranged from 2-4mm3.

When I lit one of these to test them, Ignition took a moment but when it finally went, this thing didn't crackle or pop, it exploded! does anyone know the chemistry of this comp?

I could tell by the red mark left in the middle of the blast burn and the equally loud pop from cubes half as small, that my bigger cubes weren't fully reacting(not sure of the right term)?

so I primed them my bigger cubes with this:
Micro star prime Best of AFN III
Kn03 57.4
c 11.4
s 11.4
Al(dark) 5.7
silicon 11.4
dextrin 2.9

I didn't have silicon but something I had been planing on trying was filings pulled from dirt with a magnet. Previously I tried these for spark effects but they only molted up and glowed for a while. this is the purpose silicon serves in this prime, so I thought id give it a go. Like I said I have never used silicon nor did I try plain meal but this worked fine for this purpose.

The primed eggs going off sounded more like a salute than anything else. After the prime burned up and stopped glowing the egg began to glow then BOOM!

I screened and granulated some of this comp and put some in my newly acquired glitter and pressed some comets. For my primed eggs, I rolled a few in some extra firefly comp I had, and plan to shoot them in a mine once dry.

This is some interesting stuff, so many applications.
When they dry, I will post results of crackling comets and exploding firefly stars.

Marcus

Edited by dfk, 12 March 2004 - 04:12 AM.

Marcus; 'In the practice of manipulating fire for 4 years'




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