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krimmie
March 17th, 2002, 08:49 AM
What's up people....I have what is between a question and an observation! All comments are welcome. I have purchase two separate pounds of Al from a major internet supply house;
-Indian Blackhead 8 micron flake; this stuff is great, mixes easily with KCLO4 and burns super fast.

-Al flake ,German -400 mesh; the problem with this Al is that it is so 'fluffy'.....it is hard to get a homogeneous mixture with the KCLO4. It wants to float on top of the perchlorate! I had thought I got a good mixture and tested it....one pile went poof(that's good), the other pile(from the same container) burned like a sparkler.

BTW, I use the diaper method to mix.

Besides the obvious mixing problem....anyone have any comments? :confused:

<small>[ March 17, 2002, 07:54 AM: Message edited by: krimmie ]</small>

CyclonitePyro
March 17th, 2002, 12:02 PM
As long as you're using KCLO4, and no sulfer or chlorate, it should be about as stable as flash gets. I currently use KCLO4 and german dark 400mesh, and I just put it inside a plastic container and shake... not vigerously but enough to get it thoroughly mixed. I never had an accident with it.

<small>[ March 17, 2002, 11:03 AM: Message edited by: CyclonitePyro ]</small>

krimmie
March 17th, 2002, 12:57 PM
Thanks, the sensitivity is what I was worried about. I'll try and mix with a "little" more vigor....I was being overly cautious I guess.

ALENGOSVIG1
March 17th, 2002, 03:30 PM
Well i wouldnt shake it while holding it in my hand. Diaper mix it for longer. Do it for 15 minutes or so while watching tv to get a real intimate mix.

vulture
March 18th, 2002, 01:53 PM
Add acetone to it until you have a paste. You'll get little chunks of flash which can be used as stars or be crushed (with some caution) to be used in a powder application.
I've tried this with KMnO4/Al/S flash and it was more powerful than the dry mixed version.

I would advise NOT to use isopropyl alcohol because it will get oxidized to acetone by strong oxidizers.
This is not dangerous, but it will consume oxidizer.

About safety, i've been fooling around alot with KMnO4/Al/S which is insanely dangerous according to some people and had no accidents.
To put it straight, if KMnO4/Al/S is a shitty `82 toyota, then KClO4/Al is a 2002 fancy mercedes. Got it?

krimmie
March 18th, 2002, 10:30 PM
I too have had no problems with KMnO4/Al/S....but I used 400 mesh Al with that mixture. With the KClO4 I have used 8 micron Al. There is a huge difference in the end product, depending on the size of the Al. I think 400 mesh is equivalent to 37 micron. Does a flash compound get more sensitive with finer Al? Thanks for the info.

vulture
March 19th, 2002, 12:59 PM
It gets faster for sure when finer Al.
More sensitive depends on how well it is mixed.
Very fine well mixed will be more sensitive, but because of it being finer it will mix worse. As a result there will be over/underoxidized portions, which are less sensitive.

Sparky
March 19th, 2002, 05:33 PM
Since you say the aluminum is to low density to mix with the pechlorate properly, maybe you could add some Cab-O-Sil to the perchlorate before mixing to make it more similar to the aluminum. This is fumed SiO2 used to make pyrotechnic compositions more free running and "fluffy".
One way some people like to mix flash is to tape a plastic static resistant container onto the end of a long stick, then hold it out around a corner and shake it. This method was suggested in rec.pyrotechnics (they are almost constantly talking about flash).
Since you didn't know that finer aluminum makes faster flash, I will also point out that finer perchlorate makes it faster too.

Pu239 Stuchtiger
March 19th, 2002, 09:54 PM
I would abandon the KMnO4 / Al / S compositions immediately. The dice won't roll in your favor forever.

vulture
March 20th, 2002, 09:05 AM
Look, i'm fucking sick of this! Everybody keeps telling me KMnO4 and sulfur are extremely dangerous to handle and can go off spontaneously. Mostly these are people who have made and handled AP... :rolleyes:
I have made 80g of KMnO4/Al/S flash which i stored for almost a month. I can tell you it's a bitch to set off properly, if you want it to deflagrate all at once you have to ad a significant amount of BP.
It is true KMnO4 loses it's oxygen at low temperature, but if the burning temp. of Al or S isn't reached it won't do squat!

Now unless you've got any credible SCIENTIFIC explanation for it being so freakin' dangerous i might believe you.

Pu239 Stuchtiger
March 20th, 2002, 02:04 PM
Extremely minute quantities of sulfur can be oxidized to sulfur trioxide by the potassium permanganate.

SO3 + 2KMnO4 --> Mn2O7 + K2SO4

Formation of Mn2O7 results in spontaneous ignition. The above reactions are the same reason that KClO3 / S compositions are usually avoided. The chances of spontaneous ignition are not that high, but eventually your luck will run out if you never stop playing with those compositions.

Anthony
March 20th, 2002, 02:40 PM
I think the problem is that some people say that KMnO4 flash is dangerous because it is sensitive, i.e heat/shock/friction/static etc, not that it can react and spontaneoudly ignite.

Leaving out the sulphur might give an acceptably stable flash.

rikkitikkitavi
March 20th, 2002, 04:04 PM
why is the KMnO4/al/S not sensitive? could be of a million reasons...
like crystal size, purity, relative humidity , colour of your underwear or whatever...

if the general statement is that it is very sensitive, there is a reason for it, whatever once personal experience is. to believe elsewise is step one in the application for the Darwin awards...

anyway, mixing sulfur with strong oxidizer is a sure way to get sensitive mixtures when they absorb moisture from the air.

/rickard

vulture
March 20th, 2002, 04:14 PM
Pu239, that sounds like a reasonable explanation, only it would take a lot of time until a significant amount of SO3 got produced under the influence of moisture. I usually seal those compositions and rinse them with acetone frequently to prevent that.
Anyways S is a lot cheaper then Al and it doesn't make a real difference in performance.
If anybody wants to save me <img border="0" title="" alt="[Wink]" src="wink.gif" /> give me a nice ratio for KMnO4/Al/C

<small>[ March 20, 2002, 03:15 PM: Message edited by: vulture ]</small>

Pu239 Stuchtiger
March 20th, 2002, 05:36 PM
It actually would require very little SO3 to form... 0.0001 grams of SO3 being produced would probably be enough to cause spontaneous ignition. I would replace the sulfur with carbon, just to increase safety. Substitute every 8g sulfur with 3g carbon. Moisture is not necessary for my previously stated explanation of why KMnO4 / Al / S compositions are so dangerous; moisture does increase the danger though.

krimmie
March 20th, 2002, 09:22 PM
I think I'll try that with the C...KMnO4 is much cheaper for me to get hold of. I've been only making and testing small batches at a time(15g), and storage is not a good idea in the humid environment that I live in. I have to keep the KClO4/KMnO4 and Al in the air-conditioned house(separately-of course) because of the heat outside. Thanks for the imput.

SATANIC
March 20th, 2002, 10:18 PM
well, i have only ever tried KMnO4 / S, with a little very coarse Al, and took a small amount of BP on the side to ignite it. Would't light with a lighter at all. :( )

It did however ignite more easily when crushed between concrete and a brick.

But i really replied here to ask you not to have a go at my 82' Toyota, i have a corolla from that year. :D

Rhadon
April 5th, 2002, 04:44 PM
If you really aim to light KMnO4 / S / Al with a lighter you'll do best by forming the powder to a 'pyramide'. Add some more sulfur onto the top of it and expose it to the fire until it ignites - this can take some time, especially if your 'pyramide' is very small.