MadMax Posted April 24, 2011 Share Posted April 24, 2011 Pyropow3r, I can see that regardless of what people say to you about this process being unsafe or uneconomical you intend to prove them wrong. Personally I find that powdered low micron flake Al is cheap enough commercially that it doesn't "yet" warrant creating it one's self. People have stated that you aren't going to be able to get the powder down to the micron range but it's not so much the size that makes the species reactive its more the morphology. Flake Al will always be more reactive then non-flake even much larger. It's clear from the fact that your powder has reached pyrophorosity that the species is in deed reactive enough. Putting tiny holes in the container to allow constant air flow in was my original suggestion and I still think that might be best in your setup. It seems like the most dangerous times are when you actually open your container. I don't believe that even at the micron range the oxide coating is considered the majority. But a trend is to "replace" the oxide layer with something easier to break down such as stearic acid - which is a fatty acid. But I think what's important to realize is that doesn't necessarily 100% replace the oxide layer - it just lessens it by "blocking" some of it with something that's easier to break down thermally. Ok here's a suggestion that you might try since it seems you are already starting self-igniting aluminum powders... (this is where some eyebrows may be raised - or perhaps lost entirely) Don't open it at all! Not until the end. If you want to keep your super reactive Al species mill the shit out of it without allowing it to oxidize. At the very end flood the container with a non-aqueous substance which will coat it through a tiny hole in the container. Perhaps you could try gasoline which would evaporate off most of it's volatiles leaving behind a microcoating of only the heaviest hydrocarbons - an oily layer. Or perhaps you could dissolve some red gum in 100% pure ethyl alcohol (denat) and let it dry. Then you could mill it for a few minutes more to ensure a nice even spread. Keep in mind of course that when making stars depending on what solvent you use the reactive Al may be exposed for the first time so be careful. By the way (just a random question) do you have life insurance? Link to comment Share on other sites More sharing options...
Pyropow3r Posted April 24, 2011 Author Share Posted April 24, 2011 Its not economical ? here in AUS there is no dark al present finest you can legally buy is 400 mesh.........Doesnt matter how economical it isnt its the only way to get it for me....The moral of the story roll your ownIt isnt that bad eney way its $1.50 per 100 grams plus power for the mill run it isnt really all that bad. A total of $5.00 MAX!! per 100 grams is pretty good. Link to comment Share on other sites More sharing options...
MadMax Posted April 24, 2011 Share Posted April 24, 2011 You didn't say anything about being from AUS. So you are doing it more because of unavailability. $5 / 100 grams (~ $23 / lb) is better then what skylighter has - they are now upto 40 / lb. http://www.skylighter.com/mall/product-details.asp?id=13 What are you intending to use it for? MgAl might be an option as it's easier to crush up. I have some granular MgAl and if I want it fine it takes me a couple seconds with a mortal and pestle that's how brittle it is. Link to comment Share on other sites More sharing options...
Ralph Posted April 24, 2011 Share Posted April 24, 2011 Ralph, could you flesh that though out a little more? -dag your extremely unsafe, manufactured at home composition used for increasing break strength and size may choose to self ignite at any given time Link to comment Share on other sites More sharing options...
NightHawkInLight Posted April 24, 2011 Share Posted April 24, 2011 You all are over reacting. It's not a death wish to mill aluminum as some of you seem to be suggesting. Also, who cares about how economic it is? Building fireworks to begin with is one of the most uneconomical things you can do. If your time is worth anything at all it would be far less costly to simply buy them. Whether or not it really is possible to make an Al in a ball mill that is of a size equivalent to commercial dark flake, as Mumbles said, I'll be waiting to see for myself. 2 Link to comment Share on other sites More sharing options...
dagabu Posted April 24, 2011 Share Posted April 24, 2011 Building fireworks to begin with is one of the most uneconomical things you can do. If your time is worth anything at all it would be far less costly to simply buy them. Like building a cigar box electric guitar (That was sooo freaking cool!) Link to comment Share on other sites More sharing options...
NightHawkInLight Posted April 25, 2011 Share Posted April 25, 2011 Like building a cigar box electric guitar (That was sooo freaking cool!)Nah, that only took three hours! A cigar box guitar has a tone you just can't find in anything that can be bought anyway...Also, thanks! Link to comment Share on other sites More sharing options...
Algenco Posted April 25, 2011 Share Posted April 25, 2011 Its not economical ? here in AUS there is no dark al present finest you can legally buy is 400 mesh.........Doesnt matter how economical it isnt its the only way to get it for me....The moral of the story roll your ownIt isnt that bad eney way its $1.50 per 100 grams plus power for the mill run it isnt really all that bad. A total of $5.00 MAX!! per 100 grams is pretty good. 400 mesh should be quite adequate. Other Aussie pyro's get suitable Al Charcoal grey paint pigment Link to comment Share on other sites More sharing options...
Ralph Posted April 25, 2011 Share Posted April 25, 2011 400 mesh should be quite adequate. Other Aussie pyro's get suitable Al 200mesh here http://www.diversehobbies.com/shop/index.php?act=viewCat&catId=68 makes awesome glitters 400 mesh here http://auschems.com/catalog/product_info.php?cPath=22&products_id=63&osCsid=0po14i7r0p8n0civoruhc91n21 Link to comment Share on other sites More sharing options...
nzhunter Posted March 27, 2013 Share Posted March 27, 2013 Hi all from new zealand and Currently getting ripped off with Al powder I think . $25/100g 1 micron (spherical),on offer for the same price is 3 micron dark flake.What difference will this make to flash,am I better off using dark flake?Also what are the chances of it going pyrophoric/reacting when exposed to air?Cheers all Link to comment Share on other sites More sharing options...
taiwanluthiers Posted April 5, 2013 Share Posted April 5, 2013 Freakydutchman sells 1.5kg of dark aluminum for 25 euros... it's very reactive. As for whether or not customs will let it through is another matter. Can always ask if he can label it as "charcoal gray pigment". Link to comment Share on other sites More sharing options...
Seymour Posted April 5, 2013 Share Posted April 5, 2013 Hobby metal powder seemed to be an acceptable label when I got it in. I hear what you are saying nzhunter, some of the prices in this country are so steep it's a joke. Have you got much other experience with pyrotechnics? As I'm sure you've read, it's one of the least forgiving mixtures to be making. Also, welcome to the forum! Link to comment Share on other sites More sharing options...
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