823 replies to this topic

[banga]

I'm a Mech. Eng. with a PHD in aerospace propulsion

Holy crap dude, aerospace propulsion, you must make some killer rockets! I'm running my shit by you next time I need help!

[bigtonyicu]

Ok so after talking with some of the guys in the lab, this is how they think the Eckart
5413-H is made.

So the results are most easily explained as:
Aluminum 99.458%
Elemental Carbon 0.199%
Wood ash 0.343%

And this is how they would go about making it:

They think the Aluminum foil is stretched (=thin) by roll between 2 rollers with slightly different RPM (the same way standard household aluminum foil is normally produced), when the foil is too thin to support it’s own weight, it is then backed with paper and plastic (or with some type of plasticized paper, much like butcher paper just much thinner), the roll would then be hardened (heating process to make it brittle) in a 0 oxygen environment; the paper to change to ash and volatile gasses, the plastic to soot (AKA lampblack). Once the roll is hardened it is then milled to the stated micron size.

So now that all this is said, I told them to put their money where there mouth are and replicate the results. So over the next week or 2, they will try to produce another GPC reading as close as possible to the results previously obtained.. They can replicate all the processes in the lab with the exception of milling the product to the correct size. Regardless of the size, as long as the composition is the same, we can be fairly certain that the process used by Eckart is essentially the same.

The use of this test isn’t very valuable to the amateur because it’s not really a process that can be easily replicated at home but I still can’t wait to see their results.

[Frozentech]

I've read in numerous sources that the german black aluminum is made *very* similar to the process you describe. (Reputedly) it is made by adhering the sheet aluminum onto paper with a hammer milling process, then exactly as you describe, baking it in an oxygen free retort, then hammer milling again. It's great to see someone with the knowledge *and* equipment to do an analysis like this. There are a few other I would love to see done. If you could do one on several sources of KClO4, for instance, to compare. I've started to think that the perchlorates with the 'best' reputations are contaminated, with KClO3 probably.

Ok so after talking with some of the guys in the lab, this is how they think the Eckart
5413-H is made.

So the results are most easily explained as:
Aluminum 99.458%
Elemental Carbon 0.199%
Wood ash 0.343%

And this is how they would go about making it:

They think the Aluminum foil is stretched (=thin) by roll between 2 rollers with slightly different RPM (the same way standard household aluminum foil is normally produced), when the foil is too thin to support it’s own weight, it is then backed with paper and plastic (or with some type of plasticized paper, much like butcher paper just much thinner), the roll would then be hardened (heating process to make it brittle) in a 0 oxygen environment; the paper to change to ash and volatile gasses, the plastic to soot (AKA lampblack). Once the roll is hardened it is then milled to the stated micron size.

So now that all this is said, I told them to put their money where there mouth are and replicate the results. So over the next week or 2, they will try to produce another GPC reading as close as possible to the results previously obtained.. They can replicate all the processes in the lab with the exception of milling the product to the correct size. Regardless of the size, as long as the composition is the same, we can be fairly certain that the process used by Eckart is essentially the same.

The use of this test isn’t very valuable to the amateur because it’s not really a process that can be easily replicated at home but I still can’t wait to see their results.

[bigtonyicu]

I've read in numerous sources that the german black aluminum is made *very* similar to the process you describe. (Reputedly) it is made by adhering the sheet aluminum onto paper with a hammer milling process, then exactly as you describe, baking it in an oxygen free retort, then hammer milling again. It's great to see someone with the knowledge *and* equipment to do an analysis like this. There are a few other I would love to see done. If you could do one on several sources of KClO4, for instance, to compare. I've started to think that the perchlorates with the 'best' reputations are contaminated, with KClO3 probably.

I'll get the to run some as soon as I can get my hands on some. It's next to impossible to get in Canada so I normally work with Chlorate "yes yes yes I KNOW".

As for the process for making German black Al there's definitely some lampblack so more then likely there's some source of hydrocarbon that's also burned on top of the paper and I think that's the secret. I'm hoping the guys at the ... well I don't want them to get in trouble so I'll leave that blank... have the chance to look at the sample in the Electron microscope soon I might be able find out more as soon as I get those pictures back.

[bigtonyicu]

Sorry everyone… that took longer then expected but here it is!!!



Electron Microscope of Eckart #5413-H

http://www.box.net/shared/t1zpp3i0wo

I don't know why but the scale isn't on the picture the largest particle is 4.5 micron and lots of particle are in the 0.5 to 1.5 micron range; so that 3 micron classification from skylighter must be an average.



I have a few close-up images of the largest particle and while the surface looks smooth it is in fact highly fractured; while you might expect something that size to have a surface area of 110 micron², I calculated a surface area closer to 275 micron². So with those numbers that mean that 1g has approximately the surface area 326 m², or a little more then a tennis court, so that explains the reactivity compared to spherical aluminum 3 micron, 1g has approximately 137 m², or 42% of the surface area. One could expect a flame font 2.38 times faster with the flakes.



Now I’m scratching my head on figuring out how to cut one of the larger particles in there to confirm that the dark coating is a coating and not in the particles them selves.

[Labs2008]

Hello I know this is my first post. I will get around to introducing myself later. I have just begun my journey in the art of pyrotechnics. I grew up with a friend, he and his father were Zambelli reps or something but they taught me quite a bit about shells and fireworks. Now I am quite a bit older and am interested in making my own stars and what not. I have been reading and experimenting off and on most of my life.
I recently built a ball mill and have just finished my first batch of Aluminum powder. It only took 34 hrs mill time to get 99% -100 mesh. I have compared this to my Indian blackhead and it feels and looks as fine as the blackhead. I do not have any finer screens or access to a microscope. I have tested this powder and it is not noticeably slower than the blackhead. I also ran a small 149 gram batch of aluminum foil through the blender to get it course I then cooked it with kraft paper below and above it in my charcoal making retort. The aluminum powder and charcoaled kraft were then blended and ball milled for 2 days and passed the 100 mesh screen completely. In appearance the Indian blackhead and the kraft AL powder are identical and in tests are also identical.
I am wondering if the process i am describing is similar to what the German process is and if it is chemically doing anything to aluminum powder by cooking it with the kraft?
Thanks for your time and patience in reading this post.

Edited by Labs2008, 17 August 2008 - 02:29 AM.

[MDH]

You're probably making it more reactive, or suspectable to being burnt due to the unburnt volatiles in the charcoal from the craft paper.

[Labs2008]

that is good then right?

[bigtonyicu]

OK... sorry for the delay in replying, I've been out of town,

Your retort backing with kraft, does a few things,

Kraft get converted to Charcoal, but not Lamp black,

and

On the plus side, the heating of the aluminum will help temper it making it brittle and making the ball milling process much more effective.

So what this means YES you will have relatively fast aluminum that can be easily made into very fine mesh, BUT it is not the same as German Black the black comes from Lamp Black, not Charcoal, while they are both pure carbon (for all intent and purpose) they do not behave the same what due to their different molecular structure, Lamp black is better (mostly due to it being Blacker) its main use is to absorb IR energy and speed up the reaction, this means that you should end up with fast aluminum, it speed should be between Pure aluminum and German Black (as long as the shape are the same).

IE Better then standard aluminum BUT NOT as good as German Black.



Let me know if this helps.

[Labs2008]

it helps a lot thank you

Is there a certain type of lampblack in german dark or could one use the lampblack say off of a candle or oil lamp?

Edited by Labs2008, 13 August 2008 - 07:56 AM.

[bigtonyicu]

Soot/carbon black/lamp black, they are all thing, they all have the same molecular structure.

[Labs2008]

ok thanks

[bigtonyicu]

They pay me the big buck$ to think out of the box, so I've been working very hard on company time to think of a good way to do this, might sound crazy at first but I think it would work very well please give me your thoughts.

"Toner" (for laser printer) is 85% lamp black with remainder being plastics and phenol based adhesive... might be worth trying out adding to that process instead only lamp black (as long as done in a retort) the plastic will melt leaving you with more lamblack and that few percents that remain should help bind the LB to the Aluminum, it might cool down into a block (molten plastic bridging the gaps and acting like a binder);the block should be very brittle due to the very low % of binders remaining (15% binders out of 2% initial mass is only 0.3% binder)

So it might be worth running a batch of 98% coarse aluminium and 2% toner.

Edited by bigtonyicu, 13 August 2008 - 04:32 PM.

[Labs2008]

Sounds like a good idea i think i will try toner cartrides are expensive though

[bigtonyicu]

Sounds like a good idea i think i will try toner cartrides are expensive though

Actually toner is relatively cheap, go to your local print place and ask for toner Not a Toner cartridge you should, tell them that it's not for printing purpose all you care about is the toner it's self. They should give you a plastic bottle with a large thread on it, it's made for photo copying machines, it does not contain a drum or any fancy plastic container made to be held by a laser printer, in that format it should be very cheap. You may also ask you local Toner cartridge recycling center they might be willing to sell you small quantities of toner. And well if all else fails, pull out the oil lamp and the pyrex cup lol, assuming that you have the patience, if not Skylighter.com lol, but for this purpose, and oil lamp should do nicely, you only need about 2% by weight. Let me know if you do it how it turns out, I have some guys at my lab that will be trying to make some real German black after they come back from vacation, in September