moof Posted November 1, 2008 Share Posted November 1, 2008 I am currently constructing a ball mill and I noticed a potential safety issue. My design has a pvc drum sitting on top of 4 small caster wheels. The drum will have a belt around it which would be turned by a motor. Currently, I only have the wheels mounted and I spun the drum. I noticed a lot of static was being produced, it was enough to give me annoying jolts. Can anyone give a solution to this static electricity problem since I am planning to mill black powder in this machine. And yes, I know of anti-static spray but I don't want to keep spending money on it every time I use the ball mill. Link to comment Share on other sites More sharing options...
tentacles Posted November 2, 2008 Share Posted November 2, 2008 If you plan on being a pyro long, plan on using lots of anti-static spray. To prevent the mill from being a triboelectric generator, use metal rollers (preferably ground them and the motor as well). I had a little mill for a while that operated like yours, it works but you'll outgrow it quickly. Link to comment Share on other sites More sharing options...
JS92 Posted November 2, 2008 Share Posted November 2, 2008 I dont know if you know what my ball mill looks like tentacles....but will mine generate any electrostatic energy and potentially cause a deverstating problem? Er....let get some piccys: http://i103.photobucket.com/albums/m160/porsche911GT/SL270466-1.jpg http://i103.photobucket.com/albums/m160/porsche911GT/SL270467-1.jpg http://i103.photobucket.com/albums/m160/porsche911GT/SL270468-1.jpg Link to comment Share on other sites More sharing options...
tentacles Posted November 3, 2008 Share Posted November 3, 2008 Technically, they will ALL generate some static, but using the right materials can mitigate this to some degree. The H/L-DPE jar is probably the culprit for the OP, as it is a good triboelectric generator, and is generally NOT filled with slightly conductive things. PVC pipe/sheet is generally conductive enough at high voltages to limit the charge to more reasonable levels. The lortone rubber jars are probably the best for dissipating any charge, but are pricey and difficult to keep sealed through a long run. Link to comment Share on other sites More sharing options...
moof Posted November 4, 2008 Author Share Posted November 4, 2008 (edited) I've heard that a precaution against black powder exploding from static during milling is spraying a small amount of water into the jar before time. I can't think of any reason that it would mitigate the risks, can anyone give me more information? Thanks for your reply, tentacles. I'll try to replace the rubber wheels with metal ones when I can find them. Edited November 4, 2008 by moof Link to comment Share on other sites More sharing options...
Mumbles Posted November 5, 2008 Share Posted November 5, 2008 It makes it worse actually. I still have to get around to looking it up, but I want to say it's in COPAE. Moisture up to about 6% I want to say increases the rist of ignition from static. Link to comment Share on other sites More sharing options...
ExplosiveCoek Posted November 5, 2008 Share Posted November 5, 2008 If you have FAST form Shimizu you can read that in there, Shimizu also claims that it becomes more sensitive to static. Link to comment Share on other sites More sharing options...
Frozentech Posted November 5, 2008 Share Posted November 5, 2008 I've read the exact report Mumbles refers to. There was a study by the old US Bureau of Mines showing static sensitivity of Black powder at different humidity levels, and 6% moisture was the most sensitive. I still like to have a fairly high relative humidity *outside* of the mill jar though. Where I live, I worry about the dry cold winter days more than any other time. Link to comment Share on other sites More sharing options...
aluminaball Posted November 23, 2008 Share Posted November 23, 2008 (edited) Hi, we have ball mill grinding media, if you are interested, you can contact us, thanks. MODERATOR EDIT: Read the rules before you post again. And you've been warned. Edited November 23, 2008 by TheSidewinder Link to comment Share on other sites More sharing options...
qwezxc12 Posted November 23, 2008 Share Posted November 23, 2008 Hi, we have ball mill grinding media, if you are interested, you can contact us, thanks. Wrong place to advertise...two posts so far and they're both pushing your product in the wrong manner. Please read the rules and learn some board etiquette. Link to comment Share on other sites More sharing options...
PyroMan LTU Posted December 7, 2008 Share Posted December 7, 2008 Hello, Hare is a small question: can I ballmill sugar with Sr or Ba nitrate? Thank you! Link to comment Share on other sites More sharing options...
FrankRizzo Posted December 8, 2008 Share Posted December 8, 2008 Hello, Hare is a small question: can I ballmill sugar with Sr or Ba nitrate? Thank you! Yes, though the same rules as milling black powder apply. Use only non-sparking media. Link to comment Share on other sites More sharing options...
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