Will hardened lead antimony balls wear out quickly in a ball mill?

I've read that regular soft lead balls can wear out extremely quickly and contaminate mixtures in a ball mill, but what about these hardened lead antimony balls? I don't really fancy the idea of breathing in a lot of lead dust after a couple hours of milling.


Would it be a good idea to get the lead balls from this website (found under "ball mills and media") for my ball mill (for making potentially explosive chemicals)? I've considered getting brass balls, but they are unbelievably expensive. I've also considered getting a brass bar and cutting it, but that's not cheap either and I don't know where to get a brass bar. Plus, apparently brass wears down quickly too, so it seems like a lot of trouble when I can just get lead balls, as long as they don't wear out too badly.

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Don't laugh, but I use bb's, super cheap and they work awesome.
Burf6 years ago
Lead-antimony is harder than pure lead but it is still soft. I use lead-antimony alloy for casting bullets.
Go down to a hardware store and buy a box of solid brass nuts, not plated, and use them in the mill. They're readily available in a variety of sizes, relatively cheap and they will do the job.
Hardened here is a very relative term. What's wrong with kids marbles ? Cheap and easy to get hold of.

Ke-Bob (author)  steveastrouk6 years ago
I wish I could, but marbles are brittle and they can spark.
kelseymh Ke-Bob6 years ago
Glass can spark? This is very interesting -- could you point me toward a source which documents sparking class marbles?

In the mean time, here's a nice writeup on using a ball mill to produce solid rocket fuel, including the comment (emphasis added),
I still had a little concern about using the rocks to grind black powder with all the ingredients (explosive) because some rocks can still produce sparks, though unlikely. Since I had already rejected brass bar stock, I thought about glass marbles. They are cheap, round, totally spark free. They worked GREAT creating dust consistency for everything I tried in it--charcoal, potassium nitrate and black powder.

Ke-Bob (author)  kelseymh6 years ago
I'm actually not entirely sure they actually do spark, because I've seen many sources that say glass doesn't spark (which makes sense to me), but on the other hand I've seen a couple of sources that say it is a possibility. For example here:

It says "Glass Marbles - They will chip, and there is concern over sparking. I know you probably have a million lying around, but it's not worth it."

It says "Don't use marbles or steel balls of any sort."

HOWEVER, it seems I'm not the only one who's unsure about whether or not glass sparks. If you look through this forum, the matter is debated back and forth, and shows a lot of people have read SOMEWHERE that glass can, in fact spark. Then again there's a lot of people who say thats not true, so now I have no idea if it does or not.

"They chip and contaminate your BP with glass and another reason is that they can spark IIRC. Lead is far better IMO and safer." 

Aside from that, I'd still rather use lead because having a mixture of broken glass and BP doesn't sound like a great idea. Plus, marbles aren't as heavy as lead.
kelseymh Ke-Bob6 years ago
Steel balls will definitely spark. No question.

I have no idea why someone would think that glass sparks, and it's interesting that, as you note, the comments are of the "I heard somewhere that..." (i.e., like the kid who died from eating Pop Rocks :-). Without some actual reliable source, it's hard for a practicing scientist to put much stock in it.

Unless....here's a hypothesis. I have no data to back this up, so I am not claiming it's true! Glass is a good dielectric (insulator). It's great for building up static electricity. Perhaps the concern is that by rolling the balls and powder sufficiently, you build up charge separation which eventually discharges. That will cause (actually, it'll be) a spark, which could ignite the mixture.

Like I said, I have no data support this wild-arse guess, and I am not claiming it's true (or false, for that matter). But that's a plausible theory that somebody else might have come up with...