BingBong Posted January 24 Posted January 24 Title. Is it safe to mill aluminum foil with marbles to make aluminum powder?
Arthur Posted January 24 Posted January 24 NO Marbles shed fine glass particles while milling, which then sensitise any mixture, flash powder is sensitive enough without being further sensitised.
BingBong Posted January 24 Author Posted January 24 11 minutes ago, Arthur said: NO Marbles shed fine glass particles while milling, which then sensitise any mixture, flash powder is sensitive enough without being further sensitised. I'm not going to use it for flash, I'm using it for a fountain and some stars. The local paint store here sells aluminum powder for 5 dollars per 30 grams which is insanely expensive, so I thought about making my own.
AustralianPyromaniac Posted January 24 Posted January 24 It’s not a great idea. While glass does not spark, ball mills with glass have exploded and serious hurt people, including well respected members of this forum. We can gather from this some other phenomenon is causing ignition than sparking, probably piezo electric discharge. The threat IS REAL, even if it’s unlikely and we do not fully understand how it works. It seems like the milling itself isn’t the issue, but emptying the jar can generate enough energy to cause ignition. Minerals added to the glass make sparking more likely, so if glass is used it should be clear, without any colourants at all. I have never considered the risk of glass dust getting into the powder. Marbles used to mill take on a frosted appearance after heavy use, but the loss is very minimal. If glass dust is being generated, it’s far finer than the type added to matches to increase sensitivity, and I would expect it to have a regular spherical shape with no sharp points. While these particles may be very hard, I am not convinced on this as a friction sensitivity increaser. Aluminium powder is not a hard chemical to source online, and if at all possible you should buy it. If you’re only milling it to say 100 mesh for fountains and glitter stars. The risk of ignition is very low. If you’re going finer, the risk is increased by an unknown amount, and I would recommend against it. But my feeling is the risk is still quite low, I have done this process myself without issue, but with safety protocol in place. As per Shimizu, the milling should be done under some light solvent, he recommends benzene, kerosene should work in its place. He would probably recommend alumina or brass media, which are non sparking but hard enough to mill metals. You may also want to look down that path. It’s easy to give a simple no answer to your question, as others have, but knowing the reasons behind our recommendations is far more valuable, and if you choose to ignore our recommendations, you can go in armed with the knowledge you need to do it safer. Hopefully you come out armed as well P.S. Note that milling makes “flake” aluminium as opposed to “spherical” aluminium, which may be what you need. Both will work, but google the difference and so you know what results to expect.
Richtee Posted January 24 Posted January 24 In any event, glass is kinda not massy enough and would be inefficient as having a million monkey typing randomly until War and Peace was written.
FrankRizzo Posted January 25 Posted January 25 Meh. Glass marbles work, but it's not the most efficient. YouTube user, TrollFaceTheMan has a video where he successfully uses glass marbles. There's some safety issues with that though, namely that glass is made of silicon dioxide. Metals like magnesium and aluminum are reactive enough to steal those oxygen atoms and turn glass into an oxidizer. The end result of your mill run is a very fine reactive aluminum dust mixed with an indeterminate amount of oxidizer. It's certainly not ideal.
Arthur Posted January 26 Posted January 26 One former regular here was milling with marbles and had a mill accident and lost half a hand and some fingers. The incident was attributed to the marbles chipping and the grains sensitising the mix extremely. Since then I've considered marbles as UNSUITABLE as milling media. I am rather attached to my hands and fingers and want to stay that way.
FrankRizzo Posted January 26 Posted January 26 The accident that Arthur is referring to has a thread here: https://www.amateurpyro.com/forums/topic/9798-ball-mill-explosion/
cmjlab Posted January 27 Posted January 27 Thanks for posting that FrankRizzo, I've not read that. Yikes!
AustralianPyromaniac Posted January 27 Posted January 27 18 hours ago, Arthur said: One former regular here was milling with marbles and had a mill accident and lost half a hand and some fingers. The incident was attributed to the marbles chipping and the grains sensitising the mix extremely. Since then I've considered marbles as UNSUITABLE as milling media. I am rather attached to my hands and fingers and want to stay that way. Are you able to point me in the direction of who said this and on what grounds? Would be interested in how they came to that conclusion.
cmjlab Posted January 27 Posted January 27 AustralianPyro the link to what Aurthur is referring to, is 2 posts above yours. Unless you are referring to something else?
AustralianPyromaniac Posted January 27 Posted January 27 3 hours ago, cmjlab said: AustralianPyro the link to what Aurthur is referring to, is 2 posts above yours. Unless you are referring to something else? I know about the accident. I was referencing the same thing in my first post on this thread. But I wanted to know who came up with the exact theory of glass chips sensitising the mixture.
ThrownBiscuit Posted January 28 Posted January 28 I would like to know as well; I think it would have been at least over a hundred years ago, probably longer. I know glass was used to make the H-48 rifle priming compound adopted by the US in 1898 for the Krag-Jorgenson rifle chamber in .30-40 Krag. But it would be rather interesting to find out who first used glass as a sensitizing agent.
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