Col Posted January 12, 2018 Posted January 12, 2018 I`d work on the assumption that 500x 0.5" media will occupy around one litre of volume.
Madumi Posted January 12, 2018 Posted January 12, 2018 I`d work on the assumption that 500x 0.5" media will occupy around one litre of volume. Thanks Col... Would that mean one gallon needs close to 2000? Oh, and I'm guessing it's been tried before, but in the interests of economy & diy'ing, would it work to cast lead rod 1/2" diameter & cut it into smaller 1/2" length rods? Just thinking it would be easier to cast rod than to cast balls :-) 1
Mumbles Posted January 12, 2018 Posted January 12, 2018 A 1 gallon jar should be half full of media, or a little less than 2L or about 1000 according to Col's calculation. From experience I can tell you that you probably need closer to 1200-1300 though. Yes, you can certainly cast rods and cut them to size. You will probably want to mill them a bit without anything else when you're done to knock down any edges and burrs. You'll need probably 33% less than with balls, but still, Casting over 800 sounds like it's going to suck either way. 1
Col Posted January 12, 2018 Posted January 12, 2018 I cast 20kg over a long weekend, rotating two 8-ball molds made it easier but it was still a tedious old job. 1
Madumi Posted January 12, 2018 Posted January 12, 2018 Yes, you can certainly cast rods and cut them to size. You will probably want to mill them a bit without anything else when you're done to knock down any edges and burrs. You'll need probably 33% less than with balls, but still, Casting over 800 sounds like it's going to suck either way. Sounds good... I see most people using balls rather than rods... Are balls preferred (higher point pressure between the balls I guess?) And soft lead goes fairly cheap... If I used that, would it be worth throwing in some tin to increase the hardness (don't know if I want to bother with antinomy)?
OldMarine Posted January 12, 2018 Posted January 12, 2018 If you can find old linotype it works great for hardening led since it has a high antimony content. I used it and high antimony bar solder in mine but I got sick of pouring it and just ordered some from Caleb. 1
stix Posted January 13, 2018 Posted January 13, 2018 (edited) . . . Are balls preferred (higher point pressure between the balls I guess?) I would think that rods would be more efficient at grinding. I used to think that a ball mill worked by crushing the composition by the media falling from a great height and smashing into each other. I've since learned that it works by "grinding" as the media rubs against each other and the composition. btw. I get approx. 600 1/2" balls per litre. This was based on the theoretical packing density of same sized spheres in a cylinder being approx. 65% of the volume. [EDIT] made an error - changed 70% volume to 65% (as per my original calcs) Although mostly theoretical, this post may also be of interest:https://www.amateurpyro.com/forums/topic/12772-miscellaneous-misc-pyro-file-ball-mill-specs-v12-solution-folderzip/ Edited January 13, 2018 by stix 1
Boophoenix Posted January 13, 2018 Posted January 13, 2018 I dug up some of my old figures from a group stainless purchase did a while back. I calculated 26.3 pounds for a rebel jar or 3.7 pounds for a small jar. This is figuring at 54 balls per pound. That comes to 1420 pieces per Rebel jar ( 5 quarts ) so assuming your jar is one quart that’d be 284 pieces. From the late Leadballs a quote “ 40 balls per pound. 200 balls in 5 pounds, exactly and always “ 2
stix Posted January 13, 2018 Posted January 13, 2018 . . . so assuming your jar is one quart that’d be 284 pieces. Is this calculation using 1/2" media with the Jar half full - If so, then I concur (approx. 289 balls - close enough), otherwise I've got my calculations wrong.
Boophoenix Posted January 13, 2018 Posted January 13, 2018 Yes, that is for 1/2 media sorry for leaving that out. It seems more of the standard size for our uses. Even though in the past couple of year various other sizes have come into play of which I have I have 5 sizes and variations, 2 different types, and two different shapes in some sizes.
stix Posted January 13, 2018 Posted January 13, 2018 Yes, that is for 1/2 media sorry for leaving that out. Sorry - it's still ambiguous. 1/2 inch media with Jar Half Full? - please confirm.
Boophoenix Posted January 13, 2018 Posted January 13, 2018 Those calculations are for a Rebel jar half filled. The 26.3 pounds of 1/2 stainless media should be half full. Since the Rebel is 5 quarts devide that by 5 should give you 5.26 pounds of 1/2 stainlessfor a quart jar half full. The 54 spheres to a pound was calculated by the media I had on hand checked multiple times individually and grouped. I called a US based vendor I had purchased from before and asked them about their calculations and they used 53 spheres per pound. The remaining decimals probably have little variable to performance since you’re talking less than 20 pieces. 1
stix Posted January 13, 2018 Posted January 13, 2018 (edited) Thanks for that Boopheonix. looks like my calculations are similar enough. The remaining decimals probably have little variable to performance since you’re talking less than 20 pieces. Can you please explain what you mean by this?... 20 pieces? Edited January 13, 2018 by stix
Boophoenix Posted January 13, 2018 Posted January 13, 2018 With 26.3 pounds of stainless the extra quarter of a pound or 0.3 pounds is closer to 16 individual spheres of the media for a Rebel jar. Which is about one percent of a charge for that jar making it fairly insignificant for our purposes. If you got that detailed you’d be loading a jar differently depending on moisture content of you chemicals and/or the variation in the density of your charcoals to get a 1/4 load of BP to be milled. I haven’t compared density of media sizes from diffent batches of the same size from different vendors because I don’t have the materials to do so. Each size of media I have came from all the same sources. On a smaller jar though the percentage is higher at around 5 percent. Which still really isn’t making much difference I wouldn’t think. Lots of the media is sold by the pound. Most of the vendors of small bulk products weigh them instead of sitti;g a guy there counting piece by piece. At production they could be counted by the machine and weighed for accuracy, but once a second player joins the game it’s unlikely they’ll weigh the parts. Buy nails from and older hardware store they sold them by the pound at a much better price than the boxed nails from the big box stores. I ordered 30,000 spheres in the buy I did in two different sizes I wasn’t about to double check the count. I had also previously ordered 20,000 and 150 pieces from another vendor. The 150 I might count, but the 20,000 that filled about 6 rebel jars in that size I had to pass. I did how ever do some weighing for my original purposes. I have a lab scale that weighs to 0.01 grams pretty darn accurately. I weighed over a dozen pieces from the sample supply I purchased and then weighed in blocks of 10 and 20 multiple times to see if the math worked. It did and that’s what a based my order numbers on and distribution. 1
Boophoenix Posted January 13, 2018 Posted January 13, 2018 Maybe Lloyd can comment on my above statement. We’re friends and often have varied opinions. He knows way more about the specifics of milling as it pertains to the technical stuff than I do. I’d value his input, but wouldn’t change my personal load sizes I don’t think.
stix Posted January 14, 2018 Posted January 14, 2018 Thanks for the info. Yeah, I wouldn't be counting 30,000 pieces either
Fatall209 Posted February 8, 2018 Posted February 8, 2018 Thanks Col... Would that mean one gallon needs close to 2000? Oh, and I'm guessing it's been tried before, but in the interests of economy & diy'ing, would it work to cast lead rod 1/2" diameter & cut it into smaller 1/2" length rods? Just thinking it would be easier to cast rod than to cast balls :-)ya doesnt take long n they will be round
SKC Posted April 11, 2018 Posted April 11, 2018 The thread that I remember from Dagabu about BB's accident: https://www.amateurpyro.com/forums/topic/9798-ball-mill-explosion/?do=findComment&comment=128158 Hi PeteyPyro, I've gone through the incidence of BB with the thread you shared. You're repeatedly asking to use PPE. BTW, what is PPE(I'm a newbie). I've just ordered for a ball mill & have no problem to collect led balls. Regards, SKC
starxplor Posted April 11, 2018 Posted April 11, 2018 PPE is "personal protective equipment". It is a term used when the exact level of protection is different based on situation. Things that may be referred to as PPE include full firefighter suits, down to latex/nitrile gloves and everything in between.
PeteyPyro Posted April 12, 2018 Posted April 12, 2018 I keep my PPE ready to wear, on the chair in front of my shed. I can't get to my pyro gear without being 'confronted' by it first. I can't accidentally forget it. I'm an intact old pyro, and want to stay intact and get even older. Please faithfully wear appropriate PPE.
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