BengalFlair Posted January 29, 2014 Share Posted January 29, 2014 It was not a dead blow hammer; it was made of solid iron. With the term ‘dead blow’ I actually meant intense blow. I just used the thin al foil laminated to paper (which is usually in a cigarette packet) to prevent scattering of composition during hitting. After some intense blow, the thin foil tore apart into pieces and was being unable to protect the composition in any way and if you have some previous experience you would easily guess its condition after hundreds of hitting even with a dead blow hammer. It is for your information that I also tested it wrapped with a tissue paper with same result. I just wanted to verify it which I learned from various authentic sources and tried to find the truth behind the incidents The reaction between two thin plates (here the oxide layer of ball bearing and the al foil) may not occur in a same manner, which are between powders in a composition. According to collision theory the particles of the reactants must collide each other with right orientation, angle and with sufficient energy to initiate a reaction which may happen between two plates due to their rigidity .On the other hand the free small particles in a composition would change their orientation and angle of collision randomly during impact and get less energy from impact due to their individual small size. So if a reaction happens between two plates of different materials due to impact, it must not always be bound to occur in powder form of those materials in a composition with the same. I stated in my previous post that surface layer of naturally exposed lead contains a complex mixture of compounds of mainly carbonate and hydroxycarbonates. There may be some oxide (most probably PbO which is less reactive than Pb3o4) in that mixture but it is extremely small fraction of those compounds which hardly shows its colour in the layer. Due to this reason lead looks some shades of gray but never yellow, red or brown (oxide colour) naturally and I think a trace amount of oxide mixed with such retardants would not be able to initiate a thermite reaction practically due to impact or friction. Although I have not tried it yet, I am sure no reaction would happen if I replace the rusty ball bearing with a tarnished lead ball. Shimizu’s statement is not just a conception; it is based on some shock and sensitivity tests with some instruments carried out by him which require a small sample of a composition. So there is no way to assume that it matters only for bulk composition and Shimizu stated nowhere like that. According to the incident, how much exothermic a composition is not very important here but it is extremely important that how much shock and friction sensitive they are. In that respect I just wanted to mention that Pbo2 is highly sensitive and not only that it inflames on trituration with sulfur. So it is hard to believe that lead thermite reaction was the cause of that incident which failed to explain the both cases (ball mill and grinder explosion) with same batch of magnalium. Link to comment Share on other sites More sharing options...
pyroChile Posted April 30, 2014 Share Posted April 30, 2014 Hello to all! It could be a wet milling process with alcohol and oleic acid?. Because aluminum can be ground in this way. Best, =) Link to comment Share on other sites More sharing options...
taiwanluthiers Posted May 1, 2014 Share Posted May 1, 2014 By the way, Carbon Dioxide is not inert enough for magnesium or magnalium... it burns in CO2 as well as it burns in oxygen! You will need to use a noble gas like Argon. Link to comment Share on other sites More sharing options...
jessoman Posted May 4, 2014 Share Posted May 4, 2014 (edited) Hmm, a very interesting topic. I remote rocket blend my home made magnalium in VERY SHORT intervals. I open up the jar in stages (half open) then let sit. Then full open. And screen out the fines I need.I can't buy MgAl where I am so I have had to do it. Lucky I don't use much of it. But it's still necessary. ... I'm just waiting til it goes up :/I always wear full face mask and special coat when doing it. Over kill but... That's MgAl!I do about 30 grams at a time. And I in no way am encouraging anyone to do it. Edited May 4, 2014 by jessoman Link to comment Share on other sites More sharing options...
pex Posted May 4, 2014 Share Posted May 4, 2014 I have a question. Is it possible to use line seed oil. In the koffie ginder. I think wen you got ennough oil. You can grind it verry small? Without sparks? Did somebody try this? Pex Link to comment Share on other sites More sharing options...
Oinikis Posted May 4, 2014 Share Posted May 4, 2014 (edited) I have heard about using oil to increase the stability of metal powder. it makes sense, since oil coats the powder, protecting it from air and moisture. but maybe machine oil without any additives should be used, becouse seed oil might have some moisture in it. i think when ballmilling few mililiters for whole batch should be ok, because machine oil is able to spread into very thin layers. in my opinion fresh engine oil would be the best choice, since its thin and runny, and designed to work with metal, becouse some engines have aluminium or magnalium parts inside (i know WV Golf II gear box is made out of magnalium, and i've tried it, burns darn well). Although i don't think milling metals in coffee grinder is a great idea, since it's not sealed and it can spark.EDIT: Out of curiosity i went into garage, took small amount of aluminium powder, mixed in few drops of fresh motor oil (it mixed in quite easily). The powder stopped dusting, even if i blew air at it. then i tried igniting it. the oil in powder ignited, and after reaching sufficient heat, powder ignited, and burned in bright white flame like aluminium does. Should have tried mixing it with KNO3, oh well. Now the problem is getting oil out of the powder (or most of it). If you would to spread aluminium onto multiple sheets of paper, and put some more on top, in warm place paper should absorb the oil. Forgot to mention aluminium was bright flake. Edited May 4, 2014 by Oinikis Link to comment Share on other sites More sharing options...
Bobosan Posted May 5, 2014 Share Posted May 5, 2014 Some reference reading material for those interested in milling metals; manufacturing of flake aluminum powder.pdfMetal Flake Production.docMetal Powder Milling NASA.pdfMetal Powder Reactions During Ball Milling.pdfMIL-DTL-382D.pdf 1 Link to comment Share on other sites More sharing options...
pyroChile Posted May 5, 2014 Share Posted May 5, 2014 Some reference reading material for those interested in milling metals; Thanks! =) Link to comment Share on other sites More sharing options...
Blaster5337 Posted November 18, 2014 Share Posted November 18, 2014 First and foremost, I'm glad your ok! What happened to you is obviously not funny, but the way in which you presented the scenario had me rolling! Sorry! Thanks for your post, being a new guy this is a very informative read. On a separate note, is it possible/ok to add MgAl to Ammonium Nitrate for a reactive target? Link to comment Share on other sites More sharing options...
Jakenbake Posted November 18, 2014 Share Posted November 18, 2014 I have done it before. As long as you mix and shoot on site I don't see why not. I will say there is no real benefit from using it. Nothing that Al can't accomplish alone. Link to comment Share on other sites More sharing options...
Blaster5337 Posted November 19, 2014 Share Posted November 19, 2014 Jakenbake, Thanks for the reply and input, the "no real benefit" is ultimately the answer I needed! Thanks!Any recommendations on additions for reactive targets would be appreciated, looking for more bang for the buck of coarse as well as any special effects that could potentially be produced upon reaction to impact. Blaster Link to comment Share on other sites More sharing options...
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