Ball mill jar size and the amount of media used

[Stinger]

Hi

 

I was wondering how much media I should use for my homemade ball mill.

I was using a 4" PVC waterpipe with endcaps, filled with 200 musket balls out of lead.

The balls are 11,65mm in diameter.

 

One endcap is filled with lead balls, but I really doubt that this is enough.

I have ball milled 1/2" thick charcoal to talc-like powder in 1 1/2 hours but I think it can be much efficienter.

 

How much BP and how much media should I load in my jar?

The ball mill is powered by a 12V accumulator, because of the terrible noise it produces while milling.

So the absolute milling time is 2h per run, thats why I want a very high efficiency, leading to that I need to know how much I should load my jar with BP and milling media.

 

Thanks very much,

 

Stinger

[pudidotdk]

Your ball mill should be filled half full of media for the optimal grinding.

You might want to check out Ned Gorski's article on ball milling in the Skylighter Newsletter archive for basic information on ball mills:

http://skylighter.com/skylighter_info_page...asp?Item=110#bp

[tentacles]

Larger mills typically need lower runtimes - most folks with 6" jars only need to mill BP for 3-5 hours to make the really hot stuff.

[mormanman]

I went to home depot today to buys an end cap, fitting and the female part for the fitting. It was going to be like $9.12 I felt so poor b/c I couldn't afford it.

[FrankRizzo]

Don't feel bad mormanman..those fitting prices are insane these days. The "Sponneburgh" jar may be simple, but the materials certainly aren't cheap. A user over on the Passfire forum reported good results using 1gal Mayonnaise (HDPE) containers. They'll only last for a few batches of powder before starting to stretch and warp, but you can probably find all you ever need for free from the local grocery/deli.

[mormanman]

Thanks Frank, I'm still depressed b/c I don't have a job yet. I'm trying to sale some charcoals and sulfur on here (APC) its not really working though.

BTW, my prices are very flexible.

I don't mean to get off topic.

[jacob]

If you can get it, HDPE gas line is said to be very good for mill jars, it's usually 8'' with a thick wall and the best part, FREE, I've got a bunch of the stuff that I'm working on makeing jars out of.

[mormanman]

If you can get it, HDPE gas line is said to be very good for mill jars, it's usually 8'' with a thick wall and the best part, FREE, I've got a bunch of the stuff that I'm working on makeing jars out of.

Would you like to share. I'm serous.

[pudidotdk]

I use it, It's quite good but mine is a tad under 4" and is then a long barrel.

A bigger diameter and shorter length would be more optimal, and I do have some ~5½ inch and will make some jars of it when I get the time.

The downside is that it is so soft so the HDPE tube i have is more or less elliptical... which sucks.

 

A good thing though is that there are no shrapnel if the ball mill should burst, the jar will get a rounded shape (or so I have heard). The media won't travel very far because of the density.

[FrankRizzo]

I'm very partial to Mike B.'s design, and will be making a few like them from a cut-up 8" HDPE mortar this spring. The o-ring seal and wing-nut fastening system are extremely convenient. Those studs are stainless hanger bolts...one end has a very aggressive wood screw thread, the other is standard all-thread so a nut can thread on. I believe Mike made his own bolts by buying stainless eye bolts, cutting off the curved portion, and threading the shank.

 

http://www.pyrobin.com/files/imga0282_1.jpg

 

Stainless Eye Bolt:

 

http://www.s3i.co.uk/image/Lag%20Screw%20Eye%20Bolt.jpg

 

Hanger Bolt:

 

http://di1.shopping.com/images/di/4c/79/55/4559333944784c5357525639416c6171584a77-100x100-0-0.jpg

[Stinger]

Hi

 

I found a coffeecan in my shed and I filled it the half way full with

lead balls.

 

But now, the balls dont make a tumbling noise, more a grinding noise.

I opened the jar and turned my ball mill on, and the media just slides in the jar, it doesnt

fall down on each other.

 

 

What is wrong here?

 

Stinger

[bmarley5780]

Sams' Club Mayo Jars... $6.00 - 1 gallon -

 

HDPE

 

Works fine with my ceramic media...

[Mumbles]

Stinger you possibly need to spin the mill jar at a higher RPM. You will probably also need to install lift bars to account for the lack of friction.

 

This being said, get a new ball mill jar if it is a metal coffee can. Metal containers are NOT a option in pyrotechnics.

[JCrewPyros]

Yeah I was thinking the same... Metal causes sparks... From what I have read that would be a disaster making BP... Boom?

 

The best Idea have seen is the pvc joint with caps... A Plastic specialty store should have all the materials... buy a few sets to use with different chems?

[jacob]

Oops I forgot to give credit where it's due, Mike B on Passfire made the jars I talked about, and the other good thing about them is even if you can't get gas line for free, a whole 6'' mortar from pyrogear is only $20, about the same cost as one 6'' PVC jar.

 

mormanman, maybe

[FrankRizzo]

Yeah I was thinking the same... Metal causes sparks... From what I have read that would be a disaster making BP... Boom?

 

The best Idea have seen is the pvc joint with caps... A Plastic specialty store should have all the materials... buy a few sets to use with different chems?

If you price out the fittings for a 6" jar, you'll see that even with cheap DWV gravity-feed rated stuff (not Sch 40 or 80) the entire assembly will cost you ~$25 or more.

 

10" of 6" DWV Pipe = $3-$5

6" End cap = $7-$10

6"X4" Reducing Coupling = $10-$12

4" Rubber Cap w/band = $5-$7

[Bonny]

I'm planning on making a new jar, most likely using 4" or larger PVC pipe, end cap and reducer. Until I do that I will contnue using empty peanut butter jars. They have worked quite well for me, lasting dozens of batches before cracking. It is a real pain when they crack though, makes a real mess.

[marks265]

Yeah I was thinking the same... Metal causes sparks... From what I have read that would be a disaster making BP... Boom?

 

The best Idea have seen is the pvc joint with caps... A Plastic specialty store should have all the materials... buy a few sets to use with different chems?

If you price out the fittings for a 6" jar, you'll see that even with cheap DWV gravity-feed rated stuff (not Sch 40 or 80) the entire assembly will cost you ~$25 or more.

 

10" of 6" DWV Pipe = $3-$5

6" End cap = $7-$10

6"X4" Reducing Coupling = $10-$12

4" Rubber Cap w/band = $5-$7

DWV is Drain-Waste-Vent pipe. It has different dimensions than sch 40 & 80 pipe. When buying the fittings be sure to match them with the pipe used. DWV is lighter weight pipe and the fittings we are concerned about in a Loyd S. type jar may not be readily had. I went down that road very recently at Menards. I perfer the sch 40 pipe anyway. I had to buy a full 10' stick of 6" pipe and need to decide how many jars I wanna build!

[FrankRizzo]

Fitting prices for Sch 40 pipe are almost twice as much. The thicker material of pressure-rated pipe/fittings is completely unnecessary.

 

They are easily had. Assuming a similar layout to the Menards here, look behind you when staring at the larger diameter Sch 40 selection. The 6" DWV caps and 6"x4" reducing couplings are on the bottom shelf, and the 4" rubber test caps are just to the left.

 

I built (2) jars with that method before finding threaded rubber cleanout plugss at McMaster and using those instead (McMaster p/n

25655K75). There's an internally threaded rubber piece that inserts into each end of the pipe, then a threaded plastic plug screws in to seal it. The advantage is that they are completely removable (both plug and insert), which allows them to be used with shorter sections of pipe for small mill runs and allow the pipe section to be easily cleaned. My only complaint is that the coarse threading allows a small amount of BP dust to migrate out during a 2 hr run. I eventually took to sealing with a bit of masking tape after loading.

 

 

http://www.plumbersurplus.com/images/prod/5/D.O.-Smith-14068-rw-59288-17472.jpg

[Frozentech]

I eventually took to sealing with a bit of masking tape after loading.

I've gotten in the habit of routinely taping the lid on my mill jars, a couple years ago I popped the lid of a commercial Thumlers jar. It raised the hair on my neck to open the lid of my mill and see a nice 200 gram pile spewed all over the place. I figure a couple strips of tape is really cheap insurance.

[pyrogeorge]

i bought dual drum rotary tumbler (6lb) and the barrel size is 4-3/4"H x 4-1/2"OD.what size of grinding media i must use?and capacity of grinding media?

[Arthur]

There really is no definitive answer! If the drum needs 6lbs of stones to polish then it will need 10 - 20 lbs of lead to fill it to the same level. However this will likely overload the bearings and motor -long term.

 

If the drum is 100mm internal the media about 10mm dia will be OK and say 6 - 10 lbs of media will be a cross between overloading the motor and bearings and underloading the mill so it will not grind properly.

 

Eventually you will also look at what you can actually get or make. one ball either way from any weight isn't going to make much difference nor is one mm either way in diameter

[Mumbles]

You'll want around 150 to 200 1/2" (50 caliber) lead balls PER jar.

[pyrogeorge]

There really is no definitive answer! If the drum needs 6lbs of stones to polish then it will need 10 - 20 lbs of lead to fill it to  the same level. However this will likely overload the bearings and motor -long term.

 

If the drum is 100mm internal the media about 10mm dia will be OK and say 6 - 10 lbs of media will be a cross between overloading the motor and bearings and underloading the mill so it will not grind properly.

 

Eventually you will also look at what you can actually get or make. one ball either way from any weight isn't going to make much difference nor is one mm either way in diameter

it has got two separate barrels 3lb capacity each barrel..

 

http://img182.imageshack.us/img182/6002/ec1gl5.jpg

[FrankRizzo]

I eventually took to sealing with a bit of masking tape after loading.

I've gotten in the habit of routinely taping the lid on my mill jars, a couple years ago I popped the lid of a commercial Thumlers jar. It raised the hair on my neck to open the lid of my mill and see a nice 200 gram pile spewed all over the place. I figure a couple strips of tape is really cheap insurance.

LOL..you too?! I've had the same thing happen with my old Lortone QT6 jar. Ned Gorski of the Bluegrass Pyro's wrote about his experience with the same thing on Passfire a few weeks back; he was using a QT12 jar.

 

Do you worry about the tape getting worth-thru and catching on one of the rollers? That always my biggest fear with putting tape on a surface touching the rollers.