Sciencemadness Discussion Board

Producing Thermite

Diablo735 - 25-3-2007 at 01:16

I am wonder how to obtain aluminum powder. I know there are many sites on the internet that sell aluminum but most of them do not ship to where I am located (Canada). Also I am in high school and making the thermite for fun with a friend. So I wouldn't have a pyrotehnic's license. I read about grinding and sanding aluminum cans, blocks, etc. but aren't there any stores that sell aluminum powder? I checked a local paint store and home depot but neither had aluminum powder for paint.
Also am wondering how to obtain iron oxide for the thermite. I have read that Electrolysis is a slow method of producting iron oxide. I also read that placing steel wool in to a container with water, some bleach, and a bit of vinegar creates iron oxide a lot faster than the electrolysis. Does that actually work, safely?

Thanks in advance.

[Edited on 25-3-2007 by Diablo735]

[Edited on 25-3-2007 by Diablo735]

ac- - 25-3-2007 at 01:26

http://www.frogfot.com/synthesis/ironoxide.html

methods of making iron oxide;)

Easy aluminium powder
http://www.roguesci.org/theforum/showthread.php?t=3169
http://www.roguesci.org/theforum/showthread.php?t=3800

[Edited on 25-3-2007 by ac-]

Levi - 25-3-2007 at 08:24

Omg! I was a bit irritated when I first read this as I'm sure it has been covered numerous times, but that first aluminum powder thread ac- provided is amazing!
Quote:
From roguesci.org thread 3169

Sonny Jim

Easy Aluminium Powder #1
Ive just came up with a really effective way of producing good fine aluminium powder with totally minimum effort.

Here's what you do.

Get a food blender, you dont even need a mill attatchment. Also have a jug of water standing by.

Now, put enough soluble material (I use NaCl) into the blender and turn it on. You want enough so the blender doesnt throw everything around, but instead sets up a kind of cycle where the stuff comes up from the bottom and gets replaced by the stuff on top, so it plunges down the middle of the blender like a sinkhole.

Now, get some aluminium foil, and rip it into smallish pieces, about 1-2" square roughly. Place these into the blender, and manually shake it a bit to mix the foil in with the NaCl or whatever. Now, turn on the blender and use it in short bursts so as not to overheat it.

The foil gets finely ground up and has no escape from the blades as there is salt all around it!

Now, add the ground up mixture to water, the salt dissolves, and now filter the Al powder and there you go. Hope this helps people out a bit. Later.


The consensus among the other members is that this process works quite well.

[Edited on 25-3-2007 by Levi]

Aqua_Fortis_100% - 25-3-2007 at 10:40

i tried some times this procedures, but i putted water instead of NaCl, because which my blender generated much more heat when i used NaCl. the water also , if the blender turned on by great time can even reaches almost a boiling point (and leaves a greyish color in water), but this is very dangerous to your blender.. In fact, my blender was badly bursted by overheating, because great time turned on... that's stupid was i !:mad: , i also tried this procedures with cooking oil instead of water, but this was very bad due the difficult in washing and drying ( i not was able to dry this, because of traces of oil), but this is said to be better by some peoples. in anyway the product is a coarse powder ( 40-100 #, i think, no more).. so to raise greatly the comminuition of the powder, the best is put this in a ball mill and turn on after, i think.. also be watchful about the little "things" you must do when milling metal powders (see in threads).

My experiments with thermite, lead me to coclude obviously which Al powder without milling is MUCH MORE hard to light in any compositions than very fine Al powder (just fine or more than 300 mesh) . first i tried use only coarse Al powder with Fe2O3 (from hardware store, bought as "Xadrez - concrete pigment"- red colour. ), but didn't work with common lighters or so. i only reached this when was used the same kind of thermite , but using very fine Al instead the crude from blender. (this very Al powder was bought as gray pigment powder on the art stores). this powder mix readily with Fe2O3, and don't need even be well mixed. This was lighted easily with a match head :D
all compositions used are 3:2 Fe2O3 : Al ..

i really need a great ball mill for make many powders and pyrotechnics, but i have no motor at the moment, and still collecting several stell and brass balls from trashes of auto stores .. free, but very boring (but i have no hurry in this :cool: )

additionally, are some others types of thermite MUCH more interesting which you can do without much effort (see http://www.sciencemadness.org/talk/viewthread.php?tid=127&am... )




about ball mill check the wouter visser's page and some related threads:

http://www.wfvisser.dds.nl/EN/ballmill_EN.html

http://www.members.shaw.ca/justin.le/grinder/grinder.html (EXCELLENT page give by evil_lurker on this thread : )

http://www.sciencemadness.org/talk/viewthread.php?tid=4053&a...


http://www.sciencemadness.org/talk/viewthread.php?tid=4173&a...


so, good luck!


Edit: be aware on several variants when making thermite or similar compositions, such proportions, quality of products, etc. one friend of I ,used almost the same procedure i used(he modified some things), which he used with fine art Al powder, and "Xadrez" (Fe2O3) and didn't be able to light the mix, even with a Mg strip !!! i don't understand why of this, but i think which is due of the water content or anoother crazy reason..
there's a video of his failed attempt : http://youtube.com/watch?v=SuHKnCs3LCY


[Editado em 25-3-2007 por Aqua_Fortis_100%]



[Editado em 25-3-2007 por Aqua_Fortis_100%]

[Editado em 25-3-2007 por Aqua_Fortis_100%]

Waffles - 25-3-2007 at 23:10

One of my very first experiences with chemistry was tying two nails in NaCl solution to a power adaptor, to make Fe2O3/Fe3O4 over the course of a week or two, and doing the aluminum-foil-in-the-blender trick for my powder. I mixed it all on a super-inaccurate postal scale, brought it out to the beach with my girlfriend at the time, and it worked beautifully :) even kept us warm for about 5 minutes.

Diablo735 - 26-3-2007 at 14:55

I thought that aluminum foil had some coating on it (read it on the internet) ... or at least mine does. You can tell because when you take a lighter to the foil it burns black and something looks like it is starting to peel. And the aluminum cans had some tin in it (also read this on the internet; was I miss led?).
Does the method of the steel wool, bleach, and vinegar work? (I couln't find an answer)

bereal511 - 26-3-2007 at 15:21

Yeah, the method for steel wool and bleach does work.

As for aluminum foil, there are certain brands that don't have a plastic coating on it, so if you can find a cheap brand, I'm sure they are coatless.

And could you check your U2U messages? I sent you a message a few days ago about aluminum powder.

[Edited on 26-3-2007 by bereal511]

Diablo735 - 27-3-2007 at 03:14

Quote:

i really need a great ball mill for make many powders and pyrotechnics, but i have no motor at the moment, and still collecting several stell and brass balls from trashes of auto stores .. free, but very boring (but i have no hurry in this :cool: )


Try a junkyard. I read there are functioning ones thrown out sometimes... or something like that but they're in old dryer and/or washer... ahh, on of those. Hope you get your motor, and which store(s) did you go to for the iron oxide and aluminum powder? And the ratios are measured in weigh not volume correct? Though I have read in some articles that by look or volume... something like that, that the ratio LOOKS, not is, a 50-50 ratio. Then where can I buy an acurate scale in Canada?

[Edited on 27-3-2007 by Diablo735]

Veruth - 28-3-2007 at 06:30

What about the iron oxide from burning steel wool? I can't remember where, but I've seen it recommended over red iron oxide. It's much quicker to make, and has worked well in all the thermite mixes I've tried with it. Of course, I've never tried red iron oxide so I can't really compare them yet.

[Edited on 28-3-2007 by Veruth]

Aqua_Fortis_100% - 7-4-2007 at 08:24

Quote:
Try a junkyard. I read there are functioning ones thrown out sometimes... or something like that but they're in old dryer and/or washer... ahh, on of those. Hope you get your motor, and which store(s) did you go to for the iron oxide and aluminum powder? And the ratios are measured in weigh not volume correct? Though I have read in some articles that by look or volume


thanks. I'm looking around anothers potential places to buy some pieces. (though the balls are very expensive! for the mill which i'm planning make big quantities of AL powder at once,therefore the quantities are at the least 3000 small balls(the smaller balls, better results and this can be improved by distributing several sizes for balls). so the motor should be enough strong for resist.
(but i'm planning first a small mill for Black Powder, with some lead balls from hunting and fishing stores, with a small motor.. maybe a fan motor).
i'm disappointed with my country, because anyone know a ball mill. here ,if anyone want a mill, should do it yourself.. and also i've heard from some persons which small ball mills can be found at wal-mart stores (and also from pyro supplies as united-nuclear or another similiar).

my iron oxide is from hardware stores ,as red pigment for cements and others things, and was quite cheap. the much more expensive was the Al powder.. something as a pigment "bronzing aluminium" from art stores(easy source for small amounts of really FINE Al, but VERY expensive).

egloskerry - 7-4-2007 at 09:15

I managed pick up 5lbs of 625 mesh Al from a guy on ebay for 37$, but yeah, he doesn't ship to canada.

For iron oxide, I'd get it from sheffield pottery. I'm not sure if they ship to canada. I should've bought some when I made my last order. The stuff is only 1.35 a pound for both red and black, and if you buy 5lbs, it comes out to only 1.20 a pound. Dammit, I'm kicking myself for not buying some of that.

Diablo735 - 9-4-2007 at 21:46

Another thing I found out about about iron oxide production is that soaking the steel wool in vinegar will apparently remove the protective coating on it. Then from there it can just be left out to oxidize, but I assume it will be time consuming. Bleach, electrolysis, and burning.

chemrox - 9-4-2007 at 22:01

I tried a ball mill to render Na2CO3 grains into powder and it didn't work very well. I turned the stuff in a bottle with glass marbles for 18 hours and the grain size didn't change enough to consider doing it longer. My ball mill is a rock polisher type deal consisting of a motor, rollers and cylinder to hold the materials. I put my container with the marbles inside the larger container. I thought the eccentric rotation woudl enhance the grinding.

Levi - 10-4-2007 at 05:54

Remember that Na<sub>2</sub>CO<sub>3</sub> is a decahydrate. Have you tried baking it first to dry it out before milling?

SAM4CH - 11-4-2007 at 13:38

Best aluminum powder type in pyrotechnique is spherical type which can be produced by atomizing molten aluminum in a specific column and getting differents sizes "using ceramic nozzle in atomizer"!!

seb - 11-4-2007 at 21:20

I had made thermite as a child and was unsatisfied with the quality of the resulting iron. Another expt requiring Al powder is Al + I2 and add a drop of water (purple smoke). To get the Al pwdr I filed on an old pot. It gave enough to "prove the principle"

Now, there are thermite videos on youtube, and this thermite is a significant qty, and for this I would just attend a RR yard where they are installing a new W-shaped section, and they bring big crucibles that give copious amts (I have good chunks of pebbly, crystallized iron now). Thermite crucibles come ready-made from France, and are lit with a torch.

Aqua_Fortis_100% - 11-4-2007 at 22:23

Quote:
originally posted by egloskerry :
I managed pick up 5lbs of 625 mesh Al from a guy on ebay for 37$, but yeah, he doesn't ship to canada.


WHAT?!?! 5 lbs of very fine Al mesh and for 37US$ ? this seems to be a gold mine... i thought which (where you live? USA?) the permission is about 2 pounds per year for each person(?)..(unless this is not the black german kind )
a question: what you plan to use this enormous amount of Al powder? (for me, with these amount i will pass years and years of pleasure in many and many experiments without need more Al powder...)
Quote:
originally posted by SAM4CH :
Best aluminum powder type in pyrotechnique is spherical type which can be produced by atomizing molten aluminum in a specific column and getting differents sizes "using ceramic nozzle in atomizer"!!


is this from a document intittled "the chemistry of pyrotechnichs by Spark" or similar? seems to be a good review..
but isn't the best shape of pyro aluminium the flaked kind? (especially the black flaked).

in other pyro book ,IIRC from John Donner "Impact Firecrackers"
he says which the "Bronzing powder" or the Al powder (made from coarse aluminium foil powdered plus some stearin and ball milled for 3 weeks or so) can be treated with "99% isopropyl alcohol if maximum reactivity is desired" to remove the "stearin surfactant".. and "the damp aluminium powder is allowed to dry thoroughly for a couple of days and then carefully packed in a proper container".
so i will plan to try this (also) with my bronzing powder when i buy isopropyl. (my money is a thing which i always need in great excess..many home reagents and experiments)...

DeAdFX - 11-4-2007 at 22:32

The aluminum is atomized. I hear that the PK aluminum is mediocre at best. German dark is of course way different. Anywho the Al limit only applies to German Dark.

Anywho I find the blender + alcohol + aluminum foil + atleast 20hours of time to produce ok aluminum powder (only good for thermite and that is about it).

Aqua_Fortis_100% - 11-4-2007 at 22:55

DeAdFX :
Quote:
Anywho the Al limit only applies to German Dark

hmmm.. quite interesting..
i tought before that the best are the flaked because of the shape which allows the heating up more quickly than the round particle of atomized aluminium kinds(?).. but if you said which not,then you are probably right here...
the another mention is to a especial "submicron (4000#) aluminium powder made by NASA (?) for their rockets and the process consists in vacuum vaporizing Al in a cold container with inert gas and slowly letting cold air come into the system to reduce the oxidation" ( all these mentions is from this "book")
Quote:
Anywho I find the blender + alcohol + aluminum foil + atleast 20hours of time to produce ok aluminum powder (only good for thermite and that is about it).


IIRC is this the same procedure Microtek used??
this idea of alcohol seems to be good, although the great problem is of heating (and also overheating) of the blender while turned on..in my experiments water reached a point where was TOO hot to hands and releasing visible vapours.so much more care is needed when handling alcohol..but in anyway the alcohol seems to be best...


edit: only thing i dont understood: in the second thread on RS.org "easy Al powder" the person claimed (and uploaded photos) of a "Dark aluminium" after milling with a media...
what the reason of the change in color of aluminium? isn't the Al2O3 (layer) white!?!?

[Edited on 12-4-2007 by Aqua_Fortis_100%]

[Edited on 12-4-2007 by Aqua_Fortis_100%]

egloskerry - 12-4-2007 at 05:48

Here is another auction for the 5lbs. No, it's not german dark, but I only need it for thermite, not flash powder.

auction

This guy also has 5lb Fe2O3 for 10$, and 5lb NaNO3 for 12$ (though it is only industrial grade, so very large granules). His shipping per item is average, but if you buy two items, he combines. So you could get 5lb Fe2O3, 5lb Al for 47$.

[Edited on 12-4-2007 by egloskerry]

12AX7 - 12-4-2007 at 11:00

Quote:
Originally posted by Aqua_Fortis_100%
edit: only thing i dont understood: in the second thread on RS.org "easy Al powder" the person claimed (and uploaded photos) of a "Dark aluminium" after milling with a media...
what the reason of the change in color of aluminium? isn't the Al2O3 (layer) white!?!?


Actually, the Al2O3 layer is clear, and the metal particles are still shiny metal particles.

Thing is, with particle size (low micron range) on par with the wavelength of visible light (half micron), a whole lot of reflections take place off the particles and the light gets scattered a lot. The scattered light scatters off more metal particles, and pretty soon the light isn't going anywhere and it's so attenuated by all these reflections that hardly any gets out --> it looks black.

Same reason silver, the best room-temperature conductor, makes the black color in photographs.

Tim

Aqua_Fortis_100% - 12-4-2007 at 19:20

12AX7 , Thanks by this excellent explanation! now you cleared my mind.

i remember many time ago readed anything on black german Al where the autor said that the stuff is made by grounding a mix of Al and celulose or paper and grounding more and more.. then in an inert atmosphere, heating the mix to convert the organic content into fine carbon which stick in aluminium powder surface forming a fine carbn layer and block the oxidation of the Al by the air...
but due the fact which Al and carbon seems to separate because of densities, and persons making the same black stuff without celulose or similar, and finally because of your explanation, now i think which the process readed can be probably a bullshit.