Mumbles Posted October 22, 2012 Share Posted October 22, 2012 Unfortunately there is this nasty thing called physics tends to agree that you're completely full of shit. A ball falling from twice as high as another has exactly twice the potential energy as it turns out. Thus, twice the potential impact energy. That totally rounds up to at least 10x though Actually even of you take into consideration a higher rotational speed required to achieve a higher break angle, the impact energy is increased only marginally. For a 6" jar with 1/2" lead media a ball falling from the top of a mill to the bottom has a potential energy of 16.7 mJ, and will be traveling 1.66 m/s when it hits. Similarly a ball falling from half this height has an energy of half this potential energy, though will still be traveling at roughly 1.22m/s. Assuming a properly charged mill is traveling at 60rpm and the ball then is allowed to free fall from the absolute top of the jar starting at the same speed it was traveling at (around .47m/s), the energy increases to a whopping 18mJ. It's final velocity in this physically impossible, but maximum energy scenario, is 1.72m/s. To put things in perspective a perchlorate flash made with sulfur in a 7:3:1 ratio has an impact sensitivity of around 3.5J (not mJ). But of course don't let science or reality get in the way of you trolling and acting like as jackass. Pretty easy... A ball mill running at 70-80 RPM manages to lift the lead balls 2/3rds of the way to the top of the ball mill versus around 1/3rd to 1/2 for the slow 40-50RPM mills. The lead falls from upto twice the height and has a much higher velocity strike speed. Twice as high isn't twice the impact. It's multiple times the impact pressure. I think the ratio is 10x per each doubling in height like earthquake Richter scales or something like that. So... 10x the risk of explosion for an equivalent amount of time. Viola! Rough approximation but it works... Btw guys, make sure to make a video for this thread!!! Lets see who has the fastest powder:http://www.amateurpy...-video-contest/ Link to comment Share on other sites More sharing options...
dagabu Posted October 22, 2012 Share Posted October 22, 2012 As always Mum, you put things into perspective with science. Thanks again. -dag Link to comment Share on other sites More sharing options...
Col Posted October 22, 2012 Share Posted October 22, 2012 (edited) The impact area is very small compared to a ball rolling down a slope of media. The ball will be in constant contact with at least 5 other balls (if its on top of the heap) all the way down. A ball in mid air has a grinding potential of zero, same story when the comp is in the air. Edited October 22, 2012 by Col Link to comment Share on other sites More sharing options...
pyrojig Posted October 22, 2012 Share Posted October 22, 2012 Sounds like a frisky fellow .Pride before the fall. Your lacking proof as well, mr. fancy pant's , A simple burning of a pile of bp show very little but an idea for speed. A true test would be a linear , or sploette burn and timed. Do those videos first, then your probably going to get some competition. W/o, your making your self look silly and naive by being overly confident. Not pulling any punches here, but boastful statements v.s. asking for some competition , is a bad approach. Looks like Pyrojig can't beat my BP burn rate... Hahaha... One down... Lots more to go! Who else has slower BP than me? :D Admit defeat or make a video. Link to comment Share on other sites More sharing options...
Mumbles Posted October 22, 2012 Share Posted October 22, 2012 Agreed, those quick numbers were an absolute highest energy scenario. The increase in milling efficiency from a properly charged, tuned ball mill really comes more from a higher frequency of impacts than it does from an actual increase in energy of each collision. I did notice that when I moved to a larger jar that my powder quality did increase, so perhaps the increase in diameter increased the energy enough to make a difference in that case. There was a simultaneous increase in speed and jar diameter, as well as a media size change so it's hard to really say what was the deciding factor. Link to comment Share on other sites More sharing options...
pyrojig Posted October 22, 2012 Share Posted October 22, 2012 Mumbles....You made a great point about a larger jar and the advantages. I too was looking into this as well. It seems that the width is not as critical as overall Dia. I was designing some slender but large dia mill jars to be built here soon. It seems that it would consolidate the media into a tighter area = more contact >more grinding power! Thanks for reminding me, I kind of put that on the back burner. It will be similar to Oldguys pvc mill jars but not as wide. Agreed, those quick numbers were an absolute highest energy scenario. The increase in milling efficiency from a properly charged, tuned ball mill really comes more from a higher frequency of impacts than it does from an actual increase in energy of each collision. I did notice that when I moved to a larger jar that my powder quality did increase, so perhaps the increase in diameter increased the energy enough to make a difference in that case. There was a simultaneous increase in speed and jar diameter, as well as a media size change so it's hard to really say what was the deciding factor. Link to comment Share on other sites More sharing options...
Algenco Posted October 22, 2012 Share Posted October 22, 2012 want to check the speed of BP?Dan Creagan put a lot of effort into establishing a data base for BP using a wide vaiety of charcoalsEach batch was created under the same conditions, milling time, mill load, etc, very little could be done to improve the performance beyond what Dan acheived. http://creagan.net/fireworks/charcoal_tests.html in head to head real world testing (flight time) , my Paulownia BP is undefeated there will be a BP compotition at PGI next year, looking forward to it Link to comment Share on other sites More sharing options...
dagabu Posted October 22, 2012 Share Posted October 22, 2012 want to check the speed of BP?Dan Creagan put a lot of effort into establishing a data base for BP using a wide vaiety of charcoalsEach batch was created under the same conditions, milling time, mill load, etc, very little could be done to improve the performance beyond what Dan acheived. http://creagan.net/f...coal_tests.html in head to head real world testing (flight time) , my Paulownia BP is undefeated there will be a BP compotition at PGI next year, looking forward to it I will be taking part of that bad boy myself. The secret is urine in place of water -dag Link to comment Share on other sites More sharing options...
superspike23 Posted October 22, 2012 Author Share Posted October 22, 2012 Yes, I recommend the Lloyd Sponnenberg type PVC ball mill using Zirc M, 1/2" diameter grinding media. -dag I searched on the internet and I did not find where buy Sponnenberg Lloyd. For the media, I found. www.advancedmaterials.us/zirconia.htm 68$ for 2 kg Link to comment Share on other sites More sharing options...
usapyro Posted October 22, 2012 Share Posted October 22, 2012 (edited) Those prices are "per" KG, so that is $136 for 2 kg. I wonder how much of this media it takes to fill up a ball mill vs lead... Edited October 22, 2012 by usapyro Link to comment Share on other sites More sharing options...
Col Posted October 22, 2012 Share Posted October 22, 2012 Looks like 3.2 - 3.3kg per litre for 1/2", so maybe ~6kg to half fill a 1gal jar Link to comment Share on other sites More sharing options...
dagabu Posted October 22, 2012 Share Posted October 22, 2012 I searched on the internet and I did not find where buy Sponnenberg Lloyd. For the media, I found. www.advancedmaterials.us/zirconia.htm 68$ for 2 kg Here is Lloyds book: http://www.fireworksnews.com/product/54/2 Yup, Zirc M is expensive... -dag Link to comment Share on other sites More sharing options...
superspike23 Posted October 22, 2012 Author Share Posted October 22, 2012 why the media is so effective compared to others? Link to comment Share on other sites More sharing options...
pyrojig Posted October 22, 2012 Share Posted October 22, 2012 I will be taking part of that bad boy myself. The secret is urine in place of water -dag Cant say I'll be sticking around for the sniff test after that puppy burns!! Link to comment Share on other sites More sharing options...
dagabu Posted October 22, 2012 Share Posted October 22, 2012 Oh, you all will be down range when I test mine -dag Link to comment Share on other sites More sharing options...
superspike23 Posted October 22, 2012 Author Share Posted October 22, 2012 no scientific theory for that Just personal experiences? Link to comment Share on other sites More sharing options...
dagabu Posted October 22, 2012 Share Posted October 22, 2012 no scientific theory for that Just personal experiences? For Zirc M media? No, not just personal experience at all, it is the most efficient milling material found to date. Go ahead and look it up, you will see that it has a hardness and durability well beyond anything else currently being used. The real secret with it is using small pieces. I use 5/16" media in my 6" jars, I get a 3:1 advantage over 1/2" media as they cascade down the heap as it strikes almost three times more often them 1/2" media. -dag Link to comment Share on other sites More sharing options...
pyrojig Posted October 23, 2012 Share Posted October 23, 2012 (edited) Say, Mr Dag....If you ever run across anymore of those Zirc. media deals ,keep us posted. That stuff is amazing !!!!! It works like a charm to mill magnal to a dark pyro grade , w/o signs of wear.P.s. just because your up north doesnt mean we are all going to sniff your toxic wind (.)<:}}} lol Edited October 23, 2012 by pyrojig Link to comment Share on other sites More sharing options...
usapyro Posted October 23, 2012 Share Posted October 23, 2012 Has everyone started to switch to dark pyro MgAl instead of micron aluminum powders? If micron aluminum powders ever got restricted from the public... As long as we can still get magnesium and aluminum all is well! LoL! Link to comment Share on other sites More sharing options...
dagabu Posted October 23, 2012 Share Posted October 23, 2012 Say, Mr Dag....If you ever run across anymore of those Zirc. media deals ,keep us posted. That stuff is amazing !!!!! It works like a charm to mill magnal to a dark pyro grade , w/o signs of wear.P.s. just because your up north doesnt mean we are all going to sniff your toxic wind (.)<:}}} lol I look for it every day my friend, I should have bought it all last time but I didn't want to hog it all. Several people here and on PF got a load of it and I am happy they all did. -dag Link to comment Share on other sites More sharing options...
Recommended Posts