50AE Posted October 22, 2011 Share Posted October 22, 2011 I have trouble ball milling MgAl when it's in the state 3 to 5mm fragments. These are painfully slow to mill with my 16mm ceramic media in the 160mm drum. I'm asking what can I do to mill them. Using a blender is not an option. What if I change the media to something heavy. I can buy 22mm or even larger steel bars and cut them into sections. Will the heavier steel media help? I can also make a lift bar to make the heavy steel drop, just like a corning machine. Link to comment Share on other sites More sharing options...
Potassiumchlorate Posted October 22, 2011 Share Posted October 22, 2011 I have never milled MgAl myself, but I know those who have, and heavier media will help, but it will take quite a few hours anyway. Link to comment Share on other sites More sharing options...
Algenco Posted October 22, 2011 Share Posted October 22, 2011 stainless steel ball bearings S steel rods would , but the must be non sparking Link to comment Share on other sites More sharing options...
swervedriver Posted November 3, 2011 Share Posted November 3, 2011 Hi guys, been a while. whew, that scares me thinking about it. I did mill a few small batches a while back using ceramic media until the first time it self-combusted and blew the jar lid off. I don't know how hot the fire was, it was outside in a safe place when it happened, but the white residue all over the mill and jar looked nasty hot. No more milling MgAl for me, I'll buy the finer star comp grades and just crush and blender the rougher grades 100 mesh and bigger as needed. A blender is dangerous enough. Opening the jar after milling is scary, careful... Link to comment Share on other sites More sharing options...
50AE Posted November 6, 2011 Author Share Posted November 6, 2011 (edited) Sverve, can you give more details about the situation?1. Was the jar optimally loaded? Stuff like this has happened when a jar was very underloaded. Not personal experience, but a friendly pyro has done this with Mg powder from curiosity. He paid his curiosity with a new drum. 1.1 I suspect coarse MgAl has been put and then milled for a long time to a fine state. The finer stuff takes less volume than the big particles, so the volume diminishes.2. How long have you been milling it?3. What was your jar diameter?4. Was your mill running at a optimal speed? Edited November 6, 2011 by 50AE Link to comment Share on other sites More sharing options...
swervedriver Posted November 11, 2011 Share Posted November 11, 2011 Woops, I just re-read the op and said he was looking for larger mesh MgAl, not fine mesh. Anyhow, since you asked 50AE, 1. I suspect coarse MgAl has been put and then milled for a long time to a fine state. The finer stuff takes less volume than the big particles, so the volume diminishes. -Yes, and yes 2. How long have you been milling it? -A few hours 3. What was your jar diameter? -that mill is a hobby mill, 4 inches/ 100mm rubber barrel 4. Was your mill running at a optimal speed? -Yes ~90 rpm fwiw, ttl Link to comment Share on other sites More sharing options...
FlaMtnBkr Posted November 11, 2011 Share Posted November 11, 2011 So the larger pieces take up more volume than the finer powder? I would have assumed the opposite. That breaking it up into more pieces with air space around each, would increase volume. Is MgAl as pyrophoric as aluminum? I think I would take the lid off for a second a couple times a day regardless. Did you melt your own MgAl? I have a forge and have thought about trying it. I would need a crucible with a lid and I have heard of using sulfur as a flux to keep things from flaring up when the lid is removed or if using no lid and a reducing atmosphere in the forge. Sorry for the tangent. Link to comment Share on other sites More sharing options...
oldguy Posted November 11, 2011 Share Posted November 11, 2011 Did you melt your own MgAl? I have a forge and have thought about trying it. I would need a crucible with a lid and I have heard of using sulfur as a flux to keep things from flaring up when the lid is removed or if using no lid and a reducing atmosphere in the forge. Thread on DIY mg/al & water quenching http://www.amateurpyro.com/forums/topic/6326-water-quenching-diy-mgal/page__p__81247__fromsearch__1#entry81247 With a heavy duty SS blender run remotely, with a timer, you can reduce mg/al very quickly. Link to comment Share on other sites More sharing options...
Scrumpy Posted November 26, 2011 Share Posted November 26, 2011 I make my own, I know what you mean when you get to that difficult stage where the mill is going for ages but you dont get much powder. I wrap mine in a material (cotton) sheet and whack the hell out of it with a big hammer, you get plenty of cotton contaminating the mg/al but when you screen it you catch pretty much all of it on the first screen. Link to comment Share on other sites More sharing options...
Arthur Posted November 26, 2011 Share Posted November 26, 2011 A rod mill using rods not balls will mill to a less distributed particle size. But breaking down lumps is often well done with a hammer. Link to comment Share on other sites More sharing options...
dan999ification Posted November 26, 2011 Share Posted November 26, 2011 the bigger in diameter the rods are the more hiding space the material has and takes longer to mill.hammer or recycle it. dan. Link to comment Share on other sites More sharing options...
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