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Finally got a ball mill, Tips?


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#21 Uarbor

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Posted 17 June 2021 - 04:49 PM

I have some sandbags and concrete blocks just sitting around so I figure it wouldn't be a bad idea to put them to use as a barricade so I can run the mill in the backyard. This is another option for media as suggested above. https://www.midsouth...balls-100-count
 
I intend on mainly milling BP with lead but I got a lot of ERC to convert to charcoal then process so I figured that would be the single component milling I'd be interested in. I'll be sure to stay away from the marbles and ceramic media. Stainless steel for single components only. I suppose the small capacity of this mill won't bother too much since I was already making small batches due to my small screens I bought that prevent me from fitting my hand in to easily pass the powder through. I'll probably head to lowes tomorrow to get the oil and vinyl tubing. I assume it's gonna be 1/2"? Appreciate the input guys.

I got my tubing from advanced Auto Parts its more rubbery and grippy and durable because it is reinforced black rubber. I don't know if anyone mentioned it but it's a great idea to have a timer to shut off your Mill it will give you better consistency

Edited by Uarbor, 17 June 2021 - 05:00 PM.


#22 SharkWhisperer

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Posted 17 June 2021 - 10:13 PM

I have been using the Harbor Freight style Mill for about a month-and-a-half now. I have been using lead antimony media. I did the modifications to increase the speed of the jar. It has been making great black powder for me. Skylighter has an excellent article about how much composition to put in the Mill at one time I believe it's 125 G plus 5 lb of lead balls. The jars that came with mine started to deteriorate and I got some extra jars. I got tired of taking all day to make a pound of powder with three Hour Mill runs and 125 grams at a time. I checked around the barn and I had almost everything I needed to make a bigger Mill. The only thing I had to order was the 10 inch pulley for $17 I whipped this together in about an hour and a half this morning. I already had a large number of 50 caliber Muzzleloader balls so I can spin four jars and 20 lb of media now check it out. Obviously I will get a real mill jar someday but this will do for now I have quadrupled my capacity

Nice workaround!



#23 ThaDawg

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Posted 04 February 2022 - 03:56 PM

Sorry for the bump i'm not able to start a new topic.. is there someone who can help me calculate the pulley size for my ball mill?

#24 SharkWhisperer

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Posted 05 February 2022 - 03:33 AM

Sorry for the bump i'm not able to start a new topic.. is there someone who can help me calculate the pulley size for my ball mill?

You can start a new topic now; you just needed to have at least a first posting, which you now have. Welcome to APC.

 

If you know your motor shaft diameter and rpms, it's a simple proportional formula to calculate driven pulley rpms for any given size. D1N1=D2N2, where D1 is motor drive shaft (or disc/pulley) diameter, N1 is number of RPMs of motor shaft/pulley, D2 is driven pulley diameter, and N2 is driven pulley rpms. It's a pretty easy hand calculation, but there are online calculators available. Here's one at: https://www.engineeringtoolbox.com/pulley-diameters-speeds-d_1620.html  This particular calculator can calculate up to 4 connected pulleys. You'll only be using 2, so just put in the 3 known values (motor shaft diameter & speed, and desired final RPM) and it'll calculate the size of the final/driven pulley diameter that you want. Just ignore the remaining 2 pulleys on this calculator.

 

Desired final RPMs depend on planned container diameter to get optimal milling efficiency. There are several threads here by people who have made homemade ballmills, with detailed instructions that you can follow or use as a template to start from and modify. Lloyd Sponenberg has a book circulating on the topic that's pretty in depth. So you shouldn't have too much trouble locating answers to your questions.

 

If you aren't able to easily find the information that you want with a thread search, then just start up a new thread and folks will help with any specific questions you might have. The more detailed your questions, the easier it will be for others to give you a useful answer.

 

Have fun!



#25 Viper9399

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Posted 15 September 2022 - 06:35 AM

I use this media in my ball mill works great.

1/2-Inch Hardened Lead Ball Milling Media — Skylighter, Inc.


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#26 Arthur

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Posted 15 September 2022 - 08:32 AM

Most rock tumblers will stall if loaded with lead media. Look for ceramic (Alumina) balls the drum will turn when full. 

 

https://www.inoxia.co.uk/products/ball-mill/media/ceramic-balls-20mm Will supply to USA, certainly the best supplier I know.



#27 nordicwolf

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Posted 15 September 2022 - 10:43 AM

Thanks for the supplier link!

 

About how many would be needed for a Rebel 17 jar?

 

Woody's has ceramic media but out of stock.  I hope shipping across the pond is not too expensive...



#28 Arthur

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Posted 15 September 2022 - 11:32 AM

You'd have to message him for shipping costs and expect your country to apply import charges. Sometimes the only supplier simply isn't cheap. He might know how much is needed to fill a volume, measure the drum volume and message him  



#29 nordicwolf

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Posted 15 September 2022 - 09:07 PM

Is there any advantage to cylindrical alumina media vs round media?  One supplier suggests that "cylinder design will give optimal performance in grinding. Balls tend to roll when the cylinders will tumble causing shorter grinding sessions and better performance."

 

Thanks! 



#30 nordicwolf

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Posted 19 September 2022 - 01:30 AM

Would these alumina spheres work for ball milling?  They are advertised as a dessicant.

 

https://www.deltaads...izes=25-lb-pail

 

Thanks!



#31 justvisiting

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Posted 19 September 2022 - 08:27 AM

Those are no good. They are less dense than water and porous. I'd go with stainless steel spheres for general milling. For BP, I'd suggest you might go through the VERY laborious process of cutting brass rod stock to length and using that- the smaller the better. I'd use 1/2" diameter for a Rebel 17 jar. That would be 30+ pounds of media. You can tumble the burrs off before using it to mill BP. I used 5/8" and 3/4" diameters of the same lengths and deburred them one by one on a belt sander. They were too large, in my opinion, so I sold them cheap. 


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#32 nordicwolf

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Posted 19 September 2022 - 08:44 PM

Bummer, but thanks for checking that out.  I am hoping to find a reasonably priced USA seller of 1/2" / 13mm alumina balls / spheres.  This is not for BP but for other chems.  I have lead already but it makes things gray like pot nitrate if I mill that solo.

 

Are stainless steel spheres safe?  Are they a sparking hazard?

 

I have heard good things about alumina, hence my interest in finding that.  If SS is a safe alternative for milling individual chems that might be easier to find.



#33 justvisiting

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Posted 19 September 2022 - 10:33 PM

Pyrocreations sells 1/2" ceramic cylinders for 6.98 for 50 pcs. That's .7lb of media they say. Stainless steel is about double the weight per load, so it's about 160 bucks for the ceramic media you need for 1 Rebel 17 jar at that price. I don't know if that's reasonable. I base my calculation on a load of 16 lbs. I see they also have chromed steel balls and would never think of using them myself for milling anything.

 

Stainless steel is probably as likely to spark as alumina media if used with BP. That's a guess. I'm not a scientist. People have concerns about both media, with not much but anecdotal evidence that either of them is more or less 'safe' available. I'd say milling BP should be assumed to be UNsafe under all conditions regardless of media, and any BP mill should be located and barricaded appropriately- just in case a rare accident should occur. That's the only time you need to worry about sparks with milling. You say you have lead media. There's hard lead media and soft lead spheres. Hardened lead wears very slowly when milling complete BP. I wouldn't worry about potassium nitrate being gray from lead contamination, myself. That's assuming you are using it for BP-type formulas. Milling charcoal by itself with lead wears it very rapidly though. 

 

I'd prefer SS over alumina any day of the week, no matter what it would be used for. I do single component milling mostly. People use alumina because it's cheap, readily available, and light enough not to stall a very small mill. It's the least efficient media I've used.


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#34 nordicwolf

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Posted 21 September 2022 - 11:17 PM

Where is a good source for Stainless Steel media?

 

I have a heavy duty motor and can handle lead media in the Rebel 17 jar no problem (made some pretty good BP with it).  Pretty sure my lead is hardened.  Interesting that it will wear down with charcoal.

 

I am headed toward single chem milling which would include charcoal, so does SS media wear rapidly if milling charcoal by itself?  Thanks!

 

ps- the pot nitrate I milled could also be grey because of left over residue from the previous BP batch.  I washed down the jar and media, but still there could have been cross contamination.  I find that even after washing the lead media, it still leaves my fingers/gloves with residue I assume is BP and not lead (there is too much for it to be lead IMO.)



#35 justvisiting

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Posted 22 September 2022 - 01:11 AM

Woodysrocks.com supplied most of mine, but he seems to not carry them any more. Others were gifted to me, and  some I purchased from Craig Ball sales. I see now that they have 13mm 304 SS balls for 55.00 for 50. Slightly smaller 316 SS balls are much cheaper per ball. The 15/32 balls are 25.00/50pcs and the 11mm balls are 18.00/50pcs. I haven't shopped extensively. Better prices may be available somewhere else. Craig Ball service was very good. They shipped my order to Canada even before I paid for it!

 

Charcoal alone wears lead media rapidly because the media just falls right through it easily and wears on itself, just as it would in an undercharged mill. SS media doesn't wear to any perceptible degree when milling charcoal or any other pyro chem. The smaller media mills the charcoal to a finer powder. SS media is expensive, but it lasts forever and is corrosion resistant. If you could only buy one size, I'd go for the 15/32" for a 'one size fits all' media size in SS. The media I have is 304, but 316 is supposed to be more corrosion resistant. The SS media that I was gifted is 5/16" diameter, and mills charcoal to an impalpable powder. Most folks wouldn't bother to do such a deep dive on the subjects of BP and milling, but I found the generally accepted lore to be light on empirical data, so I got curious enough to learn a bit more.

 

I only use lead media for BP, so I never clean it. 

 

I did quite a few experiments with BP milling and single component milling. I posted my results on Pyrobin but that site is down now. If you want to PM me an email address, I could send the files to you.



#36 cmjlab

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Posted 23 September 2022 - 08:41 AM

JustVisiting,

At risk of being hollered at for unsafe milling practices, but I'd rather know now if it is unsafe....

Why not use cheaper chrome steel balls for milling single chemicals? **NOT milling B.P. or other combined chemicals, SINGLE chemical milling only**

They DO require extra maintenance (must be cleaned and dried after use, before being put away to avoid corrosion) but are far CHEAPER than stainless steel milling media, and can be purchased off Amazon here in the U.S. for ~$16.00 (U.S.)

Again for milling B.P. I only use Lead Media, mainly because I can't afford the brass or stainless steel costs.

Thanks, Charles

*Edit* I should also add that I have the space and distance to place my ballmill far from any other structures or property, and I always plan for something to go wrong when milling.

Edited by cmjlab, 23 September 2022 - 08:43 AM.


#37 justvisiting

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Posted 23 September 2022 - 02:10 PM

cmjlab, I bought cheap plated balls and the plating flaked off. Also, I once forgot plated media in a mill jar with potassium nitrate (only) and it was attacked and rusted. Those experiences turned me off. Knowing that I'd be likely to make the same mistake again, I decided to save myself from myself ;) To be fair, the media was probably poor quality seconds, knowing the vendor as I (now) do. I had an issue with his alumina media as well. He's now passed on, so no need to say who it was.

 

Everybody (including me) agrees that hardened lead is the best media for milling BP. It can't spark, and it's the most efficient. Ceramic media and SS media both have the potential ability to spark, although I've used both to mill BP, as many others have. I barricade my remotely located mill as well, as everybody should when milling live BP. I'm not suggesting that anybody mills complete BP with SS media, because I don't want to get hollered at either ;) I'm just saying I don't think alumina is any 'safer'- and I've used ceramic a lot. As soon as I switched out the alumina, my BP improved. I used my alumina spheres to mill charcoal by itself, and also to mill BP. After a long time, I noticed that the surfaces of the media had developed 'craters' from the repeated impacts. I was concerned about the degrading media forming grit that could cause an ignition, and stopped using it out of an abundance of caution.



#38 cmjlab

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Posted 23 September 2022 - 11:29 PM

Thanks for the follow-up / info. I just wanted to make sure I wasn't doing something really stupid, it works great for quick milling of individual oxidizers, just charcoal and just Mg/Al (which I realize brings a whole other set of dangers).

I'm certainly not challenging the well validated safety of lead, and am not in a position to argue for using stainless media when milling B.P. either, especially since lead works great, though most people I've heard from would use it if they could afford it (taking all safety precautions of course).

I use the plated media for single chemical milling, mainly because it's cheaper than purchasing stainless media, and is really effective. Plus, I don't have to clean my lead media since it's only used on B.P. I have not yet left the plated media in the mill jar, but I can see me working late one day and telling myself I'll get it first thing the next day.... (And that set of media would be left for no less than a week if I know myself and converted to iron oxide in a most unusable form!).

Charles



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