Brightthermite Posted August 19, 2017 Share Posted August 19, 2017 So I do not have any screens that have mesh sizes listed on them, or fine screens at all for that matter. The best I have it a metal coffee filter. I milled up some Al and was looking for a way to roughly measure its particle size. I have some 500 mesh 30 micron atomized powder and and it will not burn in a pile. My milled powder does burn in a clump however I have to light a piece of paper underneath it. So this leads me to believe it must be at least a tad smaller then 30 microns. Also the milled Al coats paper well. So does anyone know how fine Al powder has to be in order to burn in a pile? Link to comment Share on other sites More sharing options...
Mumbles Posted August 19, 2017 Share Posted August 19, 2017 Flake aluminum will burn in a pile fairly coarse. I bet something as coarse as 150 microns would burn. Without a suitable screen or microscope with a scale it's hard to estimate mesh size. Link to comment Share on other sites More sharing options...
Arthur Posted August 19, 2017 Share Posted August 19, 2017 The particle shape is at least as significant as the particle size. Spherical particles from a ball mill burn less easily, fine "flash" aluminium is not usually ball milled dry. Link to comment Share on other sites More sharing options...
Brightthermite Posted August 21, 2017 Author Share Posted August 21, 2017 The particle shape is at least as significant as the particle size. Spherical particles from a ball mill burn less easily, fine "flash" aluminium is not usually ball milled dry.I would have thought a ball mill would produce flake like partials since it more or less grinds it up? Link to comment Share on other sites More sharing options...
Mumbles Posted August 21, 2017 Share Posted August 21, 2017 It does. I'm not sure I follow either. Link to comment Share on other sites More sharing options...
Brightthermite Posted August 22, 2017 Author Share Posted August 22, 2017 It does. I'm not sure I follow either.I think he may think that I was milling pre atomized Al, like something you would buy, not turnings. Link to comment Share on other sites More sharing options...
Scorpion812 Posted September 2, 2017 Share Posted September 2, 2017 the shape of aluminum depends on its runtime in a ballmill. it also depends if you use balls as grinding media or pieces of rod, you can get both sperical and flaky al from a ballmill and convert one into the other Link to comment Share on other sites More sharing options...
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