Black Powder (Ball Mill)

[Swede]

I guess the answer on media is... 1/2 full is optimum but expensive. Smaller amounts will work, it'll just take more time. There's not much on a mill (bad speed, lighter media, etc) that cannot be overcome by milling LONGER. I think if you can shoot for 1/4 full of lead balls then it'll have a good action... but then, you'll NOT want to overload on the chems or the chems will simply cushion the media and it won't grind as well.

 

One thing that might be a prob, and I've seen this a couple times already - without enough media, there's a tendency for the chemical(s) to "cake" at both bottom and top. They get trapped there, then conglomerate, and pretty soon when you open it, you'll have two disks of badly mixed material at top and bottom, and a small load of dusty balls doing no work at all. I think that is one of the bigger reasons to use more media.

 

You can help this I think by occasionally tapping the lid and bottom of the jar with a rubber mallet to knock any stuck mixture loose, and get it back into the grind cycle.

[Swede]

On a related note, I scored another 13lb of SS bar stock the other day. I may actually get that 8" jar up to a full load of media with this, close to 50lbs.

Haha! I've spent HOURS looking online for pre-made stainless media. Flying saucer shapes, eclipsed balls, pins, needles, IT IS ALL INSANELY EXPENSIVE. The cheapest SS media I found was going for $20 or so PER POUND, so you're looking at $1,000 to load that jar!

 

Here's a Pretty good read on media in general.

[BLAST420]

Is this what you are looking for premade Stanless Steel Media..... $39.99 100 ct 1/2 in. http://www.northstarpyro.com/BALL_MILLS_ME...1_2_13MM_4.html

 

 

 

Seems like that a bit cheaper than $1000 huh?

[Mumbles]

I don't think he was talking about loading the size of mill you'll be getting. He quoted for 50lbs of SS media. I have no idea what size of mill that would be, but I'd imagine something in the 2.5 gallon range. That'd be 2500 of those 1/2 balls or so IIRC, at least to fill it. So yep, right about $1000.

[mike_au]

without enough media, there's a tendency for the chemical(s) to "cake" at both bottom and top.

I have had this problem even though my jar is about 50% full of media (500 x 0.44" lead shot in a 1.5L jar). I have found that the best solution (although a little annoying) is to put the mill on a slight angle and turn the jar over every 30-60 mins.

[FrankRizzo]

Typically, caking is a result of moisture or heat; both of which help with the integration process. Some of the best lift powders I've made were caked on opening the jar.

[psyco_1322]

http://www.northstarpyro.com/91990838.gif

 

Are those mills of good quality compared to a Tummler Tumbler? Who makes them?

[BLAST420]

Is there any danger from the lead media that is used? I have looked everywhere I know lead poisning is no good???

[50AE]

Lead poisoning ? Well, you wouldn't eat the black powder, or the contents of the ball mill ? Where's the problem ? The particles of broken lead are very little.

[psyco_1322]

Ya I can only get about 300g in my 3lb also, it sucks.

[Swede]

I will no longer use lead. I used soft lead (a mistake) and investigated what was happening in this thread.

 

In a nutshell, a 750 gram batch of BP contained TWELVE grams of powdered lead. Picture a 12 gram pile of fine lead powder. That is a lot. Even with hardened lead, you will still have, i think, significant contamination. Think of how that meal powder floats around. You inhale it by accident, gets on your hands, then you breathe it as well when it burns.

 

I switched to brass.

[tentacles]

Swede: Your lead wear compares quite favorably with Eric's (on passfire). He recently mentioned 20g of wear per 1kg batch. He was fairly specific in his quantity of media, which I can't remember, but he uses 50% 000 hardened buckshot and 50% musket balls (soft lead).

 

Lead is could be a catalyst for BP, though. Personally I'd only go with lead if you can't afford a better metal media. I certainly can't recommend spending more than scrap prices for lead media (~$.26/lb). Casting lead into brass or copper tubing isn't a bad idea, though, just be sure to use a little flux so the lead solders in or crimp the ends of each tube.

 

Maybe we should come up with a sticky topic for BP/Milling/Mills. Types of mills, speeds, sizes, media, pros/cons etc.

[Gunzway]

I own 100 1/2" solid brass ball bearings for my 3LB Ball mill.

They work great. Make sure if you buy brass make sure it is brass. Cause I was worried at first that it was not brass. Lead tends to wear out to fast and I rather brass as it is not poisonous etc. But it's your choice in the end. Just make sure it does not spark.

 

Good luck.

[Swede]

Casting lead into brass or copper tubing isn't a bad idea, though, just be sure to use a little flux so the lead solders in or crimp the ends of each tube.

I did an experiment a while back, which consisted of encapsulating #9 bird shot into copper capsules. The idea is to create a very heavy media that would function like a "dead blow" hammer.

 

I used both 3/4" and 1/2" diameter copper tube, and commercial endcaps. The problem I faced was this - I wanted to solder the endcaps, but the heat to get a good solder joint would also melt the shot inside the capsules. I ended up epoxying the caps onto the tube. It worked, but there are some problems. First, enough copper, especially the endcaps, to make a decent amount of media, is really expensive. Second, I am not confident that the epoxy bond will survive the interior of a ball mill for any length of time. I haven't tried the perhaps 20 dead-blow media I've made. I don't want to distribute bird shot throughout the mixture.

 

I like the concept. Maybe someone can improve on it.

[oskarchem]

Well, is it such a problem if you melt the lead? Solder the bottom cap on first, if the shots melt it does'nt matter, it will stay in your "capsule", then get the top one on and let the whole thing cool, the lead solidifying inside.

[FrKoNaLeaSh1010]

If the lead bird shot inside melts it is gonna stick to a wall and defeat the whole deadblow action he is trying to get where the balls inside swing and hit the endcap hitting the powder causing more force. They make deadblow hammers like that.

[mike_au]

From what I understand of the passfire article ball mills should be more of a grinding action as the media rolls rather than a pounding action. What would be the benefit of dead blow media?

[Swede]

I don't know, it was just a thought. For really lumpy charcoal, I can't help but believe blows contribute as much to the powdering as grinding. People also add those lift strips inside the jars, which also create a bit of hammer-blow action as the media falls. I'd think you'd want a bit of both.

[Bonny]

I don't know, it was just a thought. For really lumpy charcoal, I can't help but believe blows contribute as much to the powdering as grinding. People also add those lift strips inside the jars, which also create a bit of hammer-blow action as the media falls. I'd think you'd want a bit of both.

I think the lifting bars are more to prevent the media from simply sliding along the botoom as is often the case with round jars.If the jar is fully charged with media (using round balls) there will be very little hammer action as the balls will roll along over top of the rest, just after rising above centre.