Ball mill

[shaper]

A friend came over last weekend and gave me a ball mill he had just built. I wanted one to help in making my own b.p. Now I am looking for a mold with a big enough cavity to make balls about 1 inch across. I don't know of any molds that will cast a ball that big. Maybe a mold for big sinkers?
I'm open for suggestions here. If you have built one, bought one, or used one someone else built please let me know about what size ball was in the mill.
thanks
shaper

[bangerjim]

1" steel ball bearings. I have seen 3/4, 1, and 1.5" ball bearings at the salvage yard on a regular basis.

Or buy one of those pendulum ball toys. They have 8 or 10 steel balls hanging from nylon threads.

You lead cast balls will come off in your grind. Unless you use an alloy that is 30 Bhn or higher.

banger

[blademasterii]

http://www.ebay.com/itm/50-Premium-1-Chrome-Steel-Balls-Bearing-Loose-G25-/171441219729?pt=BI_Heavy_Equipment_Parts&hash=item27eab16891 That should fix you up.

[AlaskanGuy]

I use the 12g round ball that is like .660 ish... But dont hold me to that number... I already packed the mold though... But that big ball does a fine job of crunching charcoal... Give it a try...

[MOcaster]

Personally, I'm a fan of the ceramic media. Lead, maybe, but there is no way I would use steel.

[bangerjim]

Steel and cast iron are the industry standards used in commercial ball mills for pulverizing coal in power plants and copper ore in smelters. I'm talking talc powder fine! Steel and iron last for a very long time!

Grinding soft charcoal would be a no-brainer!

banger

[lylejb]

Never ever use steel balls in a bp mill. It radically dangerous!!

Think about it, your tumbling BP in an enclosed container, and add 1 spark......

You don't need 1". Anything over 50 cal will work.

[Mustangpalmer1911]

I use a mix of pure lead 50, 54, and 58 in my mill. No reason really just what I had when I started.

[shaper]

Thanks for the info. I had thought steel balls in my powder was not the best thing to do. Willow trees grow everywhere around here, so I'm ready to start a new project.
I also have a new 8 1/2 I.D. pipe being made into a jet stove. It's going to be 24inch high so it will be heavy. I' plan to use some 4 inch thick insulation all around it. It's the same insulation I have in my powder coat oven walls. So I will be putting it on wheels so I can take it outside when I do my smelting.

[bangerjim]

Never ever use steel balls in a bp mill. It radically dangerous!!

Think about it, your tumbling BP in an enclosed container, and add 1 spark......

You don't need 1". Anything over 50 cal will work.

You are talking about grinding charcoal here NOT fully mixed black powder! I was referring to someone wanting to grind up the willow branches, not powder.

Just use common sense.......and everybody will be just fine.

banger

[shaper]

this will be used to grind the charcoal that we make from 2 inch diameter or less, limbs of the willow trees.

[bangerjim]

this will be used to grind the charcoal that we make from 2 inch diameter or less, limbs of the willow trees.

That is what I read into you query. NOT BP, but just the simple charcoal! Charcoal will NOT explode. Atomize it well enough and blow it around with forced air, add a static spark, and it might possibly explode, but not in a little ball mill. Grain dust and coal dust can explode if suspended JUST RIGHT in air at the exact correct explosive limit mix....just ask one of the owners of those gain elevators that explode in the mid west!

But use what you want and what you can find. Even bigger glass marbles! Or HARD alloy lead. I would use steel ball bearings for just charcoal.

banger

[RED333]

Go by a local garage, ask for old bearings, all the steel ball you will ever need.

[Magana559]

DO NOT use steel! ONLY lead when grinding black powder, steel can ignight the black powder and cause an explosion.

Grind charcoal coarsely and then mill potassium nitrate, sulfur, and charcoal together with lead balls. I use 1/2" hard lead balls to mill my powder. 500gr 45-70 boolits work in a pinch too.

[Moonie]

I was going to say, while I've never made BP I've read about it. Isn't the preferred method of making high grade BP to mill it all together, then create a puck (corn it), grate and grade?

I have a willow in the back yard and a friend with a vineyard, I've heard grape canes are second only to willow for making charcoal for BP.

[shaper]

the best limbs from the willow tree are no more than 2 inch diameter.

[bangerjim]

DO NOT use steel! ONLY lead when grinding black powder, steel can ignight the black powder and cause an explosion.

Grind charcoal coarsely and then mill potassium nitrate, sulfur, and charcoal together with lead balls. I use 1/2" hard lead balls to mill my powder. 500gr 45-70 boolits work in a pinch too.

OMG........he is talking about grinding willow brach charcoal and NOT mixed black powder! Steel is just fine for charcoal and to pulverize any of the other constituents ..............by themselves. Once pulverized and brought together to formulate the powder, use something that will not cause a potental ignition/spark if you wish to finalize the mix of black powder in the mill.

Use common sense, if that still exists in today's world.

banger

[Magana559]

OMG........he is talking about grinding willow brach charcoal and NOT mixed black powder! Steel is just fine for charcoal and to pulverize any of the other constituents ..............by themselves. Once pulverized and brought together to formulate the powder, use something that will not cause a potental ignition/spark if you wish to finalize the mix of black powder in the mill.

Use common sense, if that still exists in today's world.

banger

Not a good idea to grind fuels that can easily ignite with steel. Charcoal when cooked in a retort is easily ignited by a spark. Think of charcloth.
It's also pointless to mill the charcoal alone, you want to mill everything together so it binds and creates a cleaner and denser powder.
I have been doing hobby Pyro for over ten years, just not worth burning a building down over the wrong media.