FrankRizzo Posted September 8, 2008 Posted September 8, 2008 (edited) I have no idea what 75/25 Mg/Al would even be used for, but it's NOT Bug engines, that's for sure. AS41 is Mg alloyed w/~ 4% Al and ~ 1% Si. AS21 is ~ 2% Al and ~1% Si. For the price of sacrificial anodes (which are often Mg alloy, Al or Al/Zn BTW) you might as well just buy the desired material in the first place if you're worried about 4% Al, IMHO. You misunderstood what he was saying. A fellow over on the UKR forum used some magnalium he thought was a 50:50 alloy, had some problems with spontaneous decomposition, then assayed the magnalium to find it was closer to 75:25. He's saying to be careful about your feedstock for making magnalium, as it might give unexpected results. Edited September 8, 2008 by FrankRizzo
Photon_Junkie Posted September 21, 2008 Posted September 21, 2008 Hi all,I have read this thread and the entire Magnalum thread mentioned earlier. I still don't see much of a response on how to grind this material. Everyone speaks about how brittle the alloy is, and how easy it is to mill. Yet, when I take the larger particles from the Skyligher Magnaluminum and try to mill, it seems its taking forever. What I would like to know is: Has anyone else tried to mill the "leftover" parts of the Skylighter Magnalum?And if yes, what media did you use?and...how long did it take? I am using exceptionally hard ceramic media (used to grind glass) and an awesome ceramic tumbling jar. I got both from a friend who makes glass alloys for aerospace. I have milled for 8 hours and I was a little disappointed that I didn't have a lot of fines. To be honest...I was hoping to open the jar and see nothing but -325 mesh.... I know, I am silly after only a few hours; but I was salivating over the idea of turning that waste magnalum into something awesome! Thanks in advance for the help.
Mumbles Posted September 21, 2008 Posted September 21, 2008 The large mesh turnings are made of Aluminum not MgAl.
Richtee Posted September 21, 2008 Author Posted September 21, 2008 (edited) Hi all,I have read this thread and the entire Magnalum thread mentioned earlier. I still don't see much of a response on how to grind this material. Everyone speaks about how brittle the alloy is, and how easy it is to mill. Yet, when I take the larger particles from the Skyligher Magnaluminum and try to mill, it seems its taking forever.. As was mentioned earlier in the thread here...the 'filler" stuff is bascially Mg only NOT Magnalum. The large mesh turnings are made of Aluminum not MgAl. Hmm mine are mag... you mean they are not consistant? Edited September 21, 2008 by Richtee
tentacles Posted September 21, 2008 Posted September 21, 2008 More than likely the "magnalium" that is the coarse portion of the skylighter stuff is a 95/5 or 5/95 ratio - essentiall ordinary magnesium or aluminum turnings. If it's not GRANULAR, it's not magnalium(50/50). The only kinds of particles you will get with the stuff we use is shapes similar to broken glass (think tempered glass, car windows). Granules, chunks, flakes, etc. It won't look like any kind of machining particle. If it's not granular, don't mill it! You don't know if it's primarily magnesium, or primarily aluminum, and milling either can be /IS dangerous. Even MgAl can become pyrophoric when being milled, although it seems to be very uncommon.
Mumbles Posted September 21, 2008 Posted September 21, 2008 Yes, I apologise, I miss spoke. It is normally Mg I think. I got some from discount pyro once that were actually steel/iron.
Photon_Junkie Posted September 21, 2008 Posted September 21, 2008 Well, since I have an ICP at my disposal I guess I am going to solve the mystery of what those little buggers are... I just posed the question to Skylighter, asking "What are the turnings...?" I know they are not actual turnings...but for a lack of a better word. The product description is misleading, one says magnesium, the other says its a 50/50 alloy. If grinding these metals makes them pyrophoric, how do the pros do it? I added at 0.2% (by mass) of stearic acid in hopes that this would coat the freshly ground surfaces. Additionally, I have read dozens of posts of people casting MgAl ingots...how did you (or they) get from an ingot to a usable form for fireworks? It couldn't have been just by smashing it up with a hammer?!?! Finally, I am not like most pyros on this site. I can afford to just by MgAl from the other places that have no turnings. It's just that I had this leftover and I love a good mystery. So if you are frustrated by all my questions, just ignore me. Not to mention I got a free ceramic ball milling jar and free ceramic media. I am just dying to crush up stuff! Again, thanks guys (and gals) for the info!
Mumbles Posted September 21, 2008 Posted September 21, 2008 Well, the professional companies use an inert gas. I highly doubt skylighter and the like will source and keep two stocks of large mesh essentially metal chips for the two products. Grinding doesn't neccesarily make them pyrophoric, but if you're not careful it can. It's mostly only a problem when the jar is opened directly after a long milling and there are airborne particles.
tentacles Posted September 22, 2008 Posted September 22, 2008 Photon: I'd explain the home process for making MgAl, but it's been neatly summed up in this thread - http://www.apcforum.net/forums/index.php?s...c=2787&st=0 It's not that we can't afford to buy, it's fun to make it and it saves money that can now go to a better use. My Mg/Al probably costs about $2-3/lb if you include the cost of charcoal and the Mg + Al pieces. I spent $5 each making the crucibles (see the end of that thread) but that's a one-time cost. The charcoal chimney I use to light my BBQ, and I use the BBQ to hold the chimney while I'm cooking metal. To process the ingots to useable mesh sizes, I first smash with a hammer, hammer and rod, something heavy, whatever. Break it up into about 1/2-3/4" pieces. Then I stick it in my meat grinder, and gnash it up. This gets me a product that's about 8 mesh on down to airfloat. I mesh it out, save the sizes I want, and then grind the bits in a coffee grinder to size. Alternatively, you could mill the bits and every 10-15 minutes open it up and mesh out again.
Photon_Junkie Posted September 23, 2008 Posted September 23, 2008 Hi all,I just got confirmation from two different sources that the "turnings" are pure (or nearly so) magnesium. My ICP analysis showed only trace amounts of Aluminum, but pegged the instrument for Mg. Secondly, Skylighter responded and confirmed the chips are almost pure Mg. I realize most of you said this earlier in the posts; being hard-headed and originally from Missouri, I just had to find out for myself. Based on everyones comments, I stopped milling as soon as you all raised doubts. Thanks for saving my eyebrows and possibly other parts of my body I am rather attached to...
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