Introduction: Making German Dark Aluminum Powder From Foil
This is an instructional for manufacturing your own homemade German Dark Aluminum powder. Homemade aluminum powder may not be as good as Eckart aluminum powder; however it is practical for use in pyrotechnics. German Dark Aluminum powder is a particular aluminum powder that has charcoal added to it to prevent oxidation while milling. Not only does charcoal prevent aluminum from oxidizing into aluminum oxide as it mills, it also makes the aluminum powder more reactive bringing about an acceptable product for pyrotechnics. German Dark Aluminum powder is a key ingredient in many pyrotechnic compositions especially in low grade explosive compositions such as flash powder. German Dark Aluminum powder can range from a coarse grade such as 100 mesh to a super fine grade such as 7000 mesh. The finer the grade of the aluminum, the more reactive it is.
Materials:
Aluminum foil
Willow charcoal (1 tablespoon)
Ball mill (or rock tumbler)
Steel media
Measuring tape or ruler
Scissors (or your hands)
Step 1: Measuring the Aluminum Foil
Step 2: Shredding the Aluminum Foil
Step 3: Adding the Charcoal
Step 4: Ball Milling the Aluminum Shreds
Step 5: Milling Results
Step 6: Final Product
Step 7: Warning:
I myself have had an accident with a different pyrophoric metal. I ordered 100 mesh magnesium powder and ball milled 60g of it for a faster burn rate for when I mix it with one of my oxidizers. When I milled the Mg for an extended period of time without disturbing it, it flared up when I finally did open up the barrel to see how it was doing. The powder didn’t flare up violently, and thank God it didn’t because I was in my room at the time, so I was able to see that the Mg powder was a darker color and appeared to be a finer mesh. I knew not to put the fire out with water so I dumped my product and media out on the grass in my backyard. As I emptied the barrel, the Mg powder REALLY flared up into an intense blaze due to the magnesium having already flared up and the sudden abundance of oxygen. I singed the hairs on my right arm, scorched my steel media, and freighted my grandmother sitting on the bench. I would have used sodium bicarbonate to extinguish the fire but I didn't have any readily available at the time. However, the hairs on my right arm, steel media, and grandmother all eventually recovered from the incident. Later, I tried ball milling the magnesium again except this time I checked on my powder every 5-8 hours exposing it to fresh oxygen. My final product resulted in a fine Mg powder.
Step 8: Testing the Final Product
The flash powder test with the Eckart Al had a faster burn rate than my homemade Al. It gave a clean thump rather than a poof with lots of sparks like the flash powder containing my homemade Al. Both flash powders were very fast except one was faster than the other and gave off far less sparks. Both flash powders are excellent charges for deafening salutes or flash bangers or celebration sticks or flashlight crackers or whatever the heck you want to call them.
Step 9: Note:
-It’s possible to use high-alumina for media rather than steel. It should result in a faster milling time.
-For clean up I recommend that you use a towel, some cleanser, and a little water to clean out the barrel. You need the coarse detergent to rid the fine aluminum powder coat from inside the chamber. You do not want any remaining Al particles to contaminate your next element or compound that you may be ball milling.
-I’ve done some research on lead media and came across a thread on bombshock.com explaining why lead balls should not be used for crushing metal or any hard chemical. Apparently if the content in your chamber is not friable the lead will contaminate your product during the milling process. Unlike steel, lead is a soft yet heavy metal and if you try to grind a non friable substance then it is likely that your final product will have a darker tint due to lead particles being chipped off the media and milled into a fine dust. The fine lead dust is also very toxic and is a considerable hazard to your health.
-I recommend that you buy Lloyd E. Sponenburgh's booklet “Ball Milling Theory and Practice for the Amateur Pyrotechnician” if possible. It’s loaded with helpful information and even has thorough instructions on constructing your own ball mill.