inkjet Posted June 6, 2006 Posted June 6, 2006 A while back, there was a newsletter by skylighter that said that coins could be used for milling media. I don't feel like buying lead media, and i'm afraid the weight of it would break my ball mill (harbor freight tumbler, the standard one) or at least the belts. I used their suggestion, 20 nickels and 12 quarters for milling about 50g of black powder for about 5 hours, but the results were very unimpressive. I noticed that for the amount of media i use, it doesn't take up much space in the ball mill at all. The writer of the article also uses it to mill 100g of black powder. He claims that after wetting and corning, it was as good as any commercial product he had tried. My question is, should i increase the amount of nickels/quarters to mill or the amount i mill at a time, or both, to increase the power of my black powder. I'll try again in a few days and mill it for 6-7 hours. Thanks for your help.
al93535 Posted June 6, 2006 Posted June 6, 2006 Increase the media. Fill your jar up as much as possible close to half full, but at least 1/4 full. Mill for the same amount of time and test again. The more media you have the better (up to half full).
Canadian_Pyro Posted June 6, 2006 Posted June 6, 2006 32 coins is not nearly enough for efficient milling. When I make smaller batches of BP, I use a modified rock tumbler, and around 150 coins. Makes about 200 grams of high quality black powder in 3 hours or so. When coins are smashed around inside the jar, there are far more contact points created by the irregular shape than caused by balls cascading, thus making up for the weight deficite.
d4j0n Posted June 6, 2006 Posted June 6, 2006 Still, its a tradeoff between quantity of contact vs force. Coins = high quantity, low force Lead balls = low quantity, high force. Coins don't spark?
Canadian_Pyro Posted June 6, 2006 Posted June 6, 2006 Copper doesnt spark, nickel doesnt spark, and bronze doesnt spark, so no, american and canadian coins do not spark. However, I believe some british coins are plated with steel. Dont quote me on that though. I dont think coins would be effective for crushing, (ie prilled KNO3, sticks of charcoal) but they work very well for the final milling step when using the Double + Single Component Milling process, which includes milling the charcoal and sulfur together until a fine powder is achieved, then milling the KNO3 separatley to a fine powder, then milling them together. I prefer to keep the time frame associated with the final mill to a minimum, as this lessens the chance of an accident.
s25 Posted June 6, 2006 Posted June 6, 2006 What about glueing cojns together?Surely little turrets of 4 or 5 coins would be more effective??
Canadian_Pyro Posted June 6, 2006 Posted June 6, 2006 I doubt they would remain intact for long, they would probably break apart and you would be back to square one. JB weld or similar epoxy might work though.
inkjet Posted June 6, 2006 Author Posted June 6, 2006 Thanks very much guys. I'll try again with a bunch more coins added in. I just wanted to make sure that this idea wasn't hopeless. I think i'll add 100-120 pennies in.
FrKoNaLeaSh1010 Posted June 6, 2006 Posted June 6, 2006 If anything i would suggest using only nickels and quarters as pennies and dimes are probably way too light and you would get better efficiency with the heavier coins.
lacrima97 Posted June 6, 2006 Posted June 6, 2006 Nickel=5g Copper/NickelPenny=2.5g Copper/NickelDime=2.25g Copper/Zinc (I think the zinc is only on the inside.)Quarter=5.7g Copper/Nickel I do think, as someone else said, that the nickel would be the best. It has a higher weight, and for the weight, you will almost have as good a surface area per g as the quarter. Quarters are expensive anyway. I would be scared of pennys. The copper coating is thin, and I have easily cut through the copper coating and into the zinc insides. I tested to see if the zinc was exposed by dipping it into some HCl. Bubbles a-million
inkjet Posted June 6, 2006 Author Posted June 6, 2006 Ok then, I'll just add some nickels. I have a bunch of change so i'll just sort through it. I'll start at 3 hours and then test the BP every hour after that until i get satisfactory results. I know it is kind of off topic, but if i wanted to corn my BP, could i use a piece of wooden dowel, a piece of PVC, and a vice to compress it? I know that one is supposed to use a hydraulic press, but i don't have one and it isn't very high on my to-build list.
Ozzy Posted June 7, 2006 Posted June 7, 2006 I have the same ball mill as you are talking about and i used like 30 lead balls and it works fine.
Mumbles Posted June 7, 2006 Posted June 7, 2006 I use 100 50 cal lead balls in mine. It works just fine. The belts are crap to begin with. I suggest getting the higher quality ones off ebay. They're like 5 for a dollar. I have been using rubber bands to drive it for about a year and a half. I am just too lazy to get new belts. Additionally, I've been meaning to build a new mill, which I am just now getting around to.
inkjet Posted June 7, 2006 Author Posted June 7, 2006 Well, i tried adding in 55 nickels and tested it with some coarse (i'm guessing +3 mesh) charcoal and in 2 hours it was very finely powdered. Much better than before when it took about 5 hours to powder the newspaper charcoal i was experimenting with. Next up is a 100g batch of BP. I think i will mill the fuels and oxidiser separately for 2 hours each, then mill them together for 2. I may just be lazy and put them all in the same time. I also am planning on buying some spare belts of Ebay, because i lost the spare belt mine came with.
aquaman Posted June 7, 2006 Posted June 7, 2006 The ebay belts are alot stronger but they still break. I'm guessing that I can get about 72 hours on a ebay belt where as the one that came with my tumbler only lasted about 12 hours if that. I wish they made the tumblers and mills with a metal chain or something so you wouldn't have to worry about it. Any ways If I were you get about 10 belts or so. I ordered 10 from this one guy and he accidently shipped out 15 so I got an extra 5. I've broke about 3 or 4.
inkjet Posted June 9, 2006 Author Posted June 9, 2006 Ok good news guys. I milled some powder for 4.5-5 hours, added 5% dextrin, pressed it through a screen after moistening, and let it dry. I sifted out the fines and coarses over the same screen. When i tested it, it seemed to just poof away. I'm excited that i finally have some good BP and am looking forward to trying some new things. Next I'm gonna mess with some crysantheum (sp?) stars. Thanks again everyone.
FrankRizzo Posted June 9, 2006 Posted June 9, 2006 Congratulations dude For those of you having trouble with the belts on your tumblers, spend a few bucks on new pulleys to fit the existing shafts. If your motor can handle it, decreasing the ratio between the motor and drive pulleys will speed it up and make it more efficient. Also, if you get pulleys that are 4L-section (1/2"x5/16"), the belt that they use is *much* stronger than those o-ring style belts used on the cheaper tumblers.
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