55 replies to this topic

[broadsword]

What is the difference between normal aluminium powder and Dark german?
What are their seperate burning properties?
Why use one anf not the other?
Where do you buy dark german?
Just some quick questions i had after seeing this Dark German Powder

Thanks in advance

[seymour]

do you think they would ship that dark german to NZ?
I am not up to flash yet but I see that here in nz geting high quality alu powder is next to imposible, so i may as well take any chances I can get, just in case I never have the opertunity again. anyway, even if I was tempted to make flash too early I have no kclo4, or any known ways of geting it.

[BigBang]

A brief explanation..........German dark & indian blackhead type Al differ from 'normal' or 'atomised' Al in that the particles are flake shape. i.e not spherical as in the atomised type. This means they have a far greater surface area, so are much more reactive. The partical size is typically 3-6 micron.

[BigBang]

Re shipping to NZ, you can ship it anywhere if you send it correctly. I just had some german dark sent from canada. It was sent via Fed-Ex as a hasardous material. The only problem is it costs a small fortune for the postage, so you have to order loads to make it worth your while, unless you dont mind paying the postage!



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Edited by BigBang, 03 February 2005 - 12:40 PM.

[Creepin_pyro]

do you think they would ship that dark german to NZ?

In short, no. Shipping hazardous materials internationally on a small scale is not really financially viable. I forgot to add, Fed-Ex will accept hazardous materials, but it's incredibly expensive.

Edited by Creepin_pyro, 03 February 2005 - 03:42 PM.

[BigG]

A brief explanation..........German dark & indian blackhead type Al differ from 'normal' or 'atomised' Al in that the particles are flake shape. i.e not spherical as in the atomised type. This means they have a far greater surface area, so are much more reactive. The partical size is typically 3-6 micron.

NO - that is not the right explanation.

NORMAL al powder is Flake. Atomised shape is relevantly new, and has relevantly few uses (such as glitter formulations). The name - German, Indian, American and so on, refer usually to the origin of the technic that used to make that powder. The Germans roast the aluminium before milling it, while other just mill it very aggressively, turning it black for some reason (maybe the temporary removal of the oxygen layer during milling). The black colour has been the subject of a few inconclusive researches. Most of the time ? when you see the word ?blackhead? it will refer to very fine powders ranging 3-6 microns.

The fact that such powders are on Ebay are a reason for concern ? they are very hazardous, and any medium size quantity of them being sold need to be reported by the seller to the authorities.

Again, this subject has been discussed in details in other threads ? so please post any future discussion in the right thread please.

Edited by BigG, 03 February 2005 - 01:27 PM.

[BigBang]

Of course BigG you absolutely correct, as usual, but my explanation is not wrong, depending on ones point of view. These days, i feel most peolpe would consider the atomised type to be the norm, as it is much easier to get hold of, cheaper and more plentyful that the black pyro type, but we are going off topic, so lets leave it at that


Going back to my original question about milling Al, as i didnt get a definative answer, i tried milling my 350mesh atomised Al for a little over 2 days and what i got out was much the same as i put in. It hadnt been reduced in size enough, if at all, to make flash. Ive been told that the drum of my mill isnt big enough to produce a decent 'pounding' effect. So, what diameter drum size would do the job and what media should i be using?

[cat]

Of course BigG you absolutely correct

Actually it?s black because of its high carbon content. The process is simple layers of thin Al foil are sandwiched between sheets paper and heated in an inert atmosphere until the paper material is carbonized. Then the sheets are chopped, and then ground.

OK, the process is slightly more complicated, do a Google search.

-cat

[BigG]

Actually it?s black because of its high carbon content. The process is simple layers of thin Al foil are sandwiched between sheets paper and heated in an inert atmosphere until the paper material is carbonized. Then the sheets are chopped, and then ground.

OK, the process is slightly more complicated, do a Google search.

-cat

No Cat, Your explanation is one of several available ? and I would not trust goggle to tell me what is the right one when there are researches on the subject even to this day. Half of the staff on the net is of questionable quality, and while some dark aluminium powder makers know the reasons for THEIR black colour, this is not the overall case for all blackheads. As such ? please lets post any future discussion on this matter on the appropriate thread. NOT THIS ONE.

Now, back to the topic ? Bigbang, why do you think your aluminium was not reduced? Do you have any means of measuring it.

[BigBang]

I dont have sieves that fine at the moment BigG, (ive had no use for them until now) so i made a small batch of flash using the milled Al and the results were the same as before the milling, dissapointing at best.

Is it actually possible to mill Al down to say 600mesh using a small home mill? has anybody here achieved this? I begining to think if one wants black Al it'll have to be bought.



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[BigG]

I dont have sieves that fine at the moment BigG, (ive had no use for them until now) so i made a small batch of flash using the milled Al and the results were the same as before the milling, dissapointing at best.

  Is it actually possible to mill Al down to say 600mesh using a small home mill? has anybody here achieved this? I begining to think if one wants black Al it'll have to be bought. 
.

There is no doubt that the best meterials are the one you buy from professional suppliers, but it is possible to mill to very fine powder. My views on flash are known - so I'm not really going to encourage you on that

[BigBang]

BigG........what are you saying exaxctly, are you saying it IS possible to mill down to say 6-700mesh with just a small home mill?

[sasman]

I dont think you can make good Flash Al with a Small ball mill...This was one of my first questions i wanted to know when i first Re-started my intrest in pyro over a year ago..I have read on lots of forums and Rec-Pyro and have no real definitive answer?..

I have ball milled 250 mesh atomized Al powder and gave up after a week (Ball mill was 9.5 inches Dia Hexagonal Drum Milling media 25 lbs of 19mm Ball bearings)..I tried to put it thru 400 mesh screen but find that takes ages to get a tiny bit thru .With out proper screens the only way is to test burn a small amount.. which i have tried and it was virtually unignitable ..

If you coulds screen out the Fines you may have a more ignitable powder..But i reckon the amount of fines would be very small.

.I had also bought some stearin to add to the Al powder But then read some where on Rec-Pyro that you dont use stearin but Stearic acid..??.So i just gave up..Not sure what to use stearin or stearic acid ...Couldnt find a defintive answer on that either...

[richard2]

Check out rec.pyrotecnics for some recent posts on this subject. Apparantly someone managed to mill Al to a very fine particle size using 4 large steel balls and pound quantities of atomised Al. He says that he had analysed particle size using a microscope to confirm it was down to dark Al proportions and had used it in compositions requiring dark Al with success.

Rich

[sasman]

I read the post on Rec-Pyro and I would like some one on this forum to say they have reproduced His results using 4 Large Ball bearings? in 2 DAYS?..He mentions he has read Lloyds book on ball milling ?.

The milling action happens between the cascading action where the balls meet?..Unless he used a very small milling jar to so enable the balls to group together then it dont sound very plasubale?.. and then even if a small milling jar was used that would make it more ineffcient?...Take a long look at all the(years of ) post's on Dark Al and you will find It wont be that easy?..

You get lots of BullSh*t on rec-pyro thats why these Forums are good you actually get to hear from peoples real life(Hopefully) practical experiments..

Hope one of our forum members proves me wrong ..