Ball Mill

[oxyrad]

Does anyone have plans to make a ball mill for making Al powder.Or any websites with plans?????

[Jack Ruby]

We have come up with a technique for making fine Metal(usually Mg or Al) Powder.

It envolves an electric drill(Press is better), some fine grit emery cloth, an auto-body disc sanding attachement, a cardboard box(to collect the powder), a C-Clamp(to hold the Metal Bar) and a dusk mask.

You clamp your work to your bench so that it is inside the box. You will probabley have to trim the box abit(you will figure it out.

you put the sanding tool in to the drill. The place on the abrasive disc.

Now put on your dust mask and start grinding.

you may wish to add a some acetone or something else that will evaporate easily. this would help to keep the dust down, then you just use a heat gun or let it dry by itself.

If you want flakes(used for sparks) use the same set up but instead of an abrasive disc use drill bits(High Speed Steel); different Sizes will give you different sized chips(the flakes).

I hope this helped. I think this is better than a ball mill due to the rapid oxidation potential of finely powdered metal.

[zaibatsu]

Check Wouter's site <a href="http://huizen.dds.nl/~wfvisser/EN/ballmill_EN.html" target="_blank">http://huizen.dds.nl/~wfvisser/EN/ballmill_EN.html</a>
Also, Dan Williams had a ball mill on his site, but my link seems to 404 now, but I made a PDF of his site earlier, so if anyone wants it I'll upload it to theforum ftp.

[10fingers]

I made a ball mill similar to the shown at Wouters pyro page. It works very well. If you want to use it for powdering aluminum you need to fasten two strips of steel or plastic inside the drum spaced 180 degrees apart. This will cause the balls to lift and drop onto each other. Use steel balls or ball bearings. I tried it recently and it does work. Using shredded aluminum foil it achieved a really fine powder in 3 days.
The hardest part to find is the correct motor. A good place to look for these is electrical surplus stores. If you get an AC motor it will need to have a built in gear reducer. Small DC motors are nice because they are usually slower and you can adjust the speed by changing the voltage. The problem with them is you need a DC power supply. The AC motor with gear reduction is probably more expensive but you can just plug it in.

<small>[ March 30, 2002, 10:58 PM: Message edited by: 10fingers ]</small>

[Anthony]

I used a gear motor from a knackered 12v cordless drill to run a small ball mill. The handy thing is you just put the shaft attached to the roller that turns the milling jar straight into the chuck of the drill motor. The motor will run happily on a regular car battery charger.

[HOOPS123]

I'm working on a ball mill in which the motor is from a small portable fan. It was a 3 speed, so on the lowest setting I'm hoping that I can make a decent reducer without too much slippage. I may have to look for a surplus store like the one mentioned above, seems more convienient.

[oxyrad]

The plans on this site look good and easy.I will get an old motor from a drill and hopefully make a mill similar to this.The drill press idea seems good aswell but i dont have a press.Iv been fucken around with a manual coffee grinder but it is to hard and dosnt end up fine enough.

[nbk2000]

Here's a site offering free samples of steel milling media (stell balls).

<a href="http://www.steelmedia.com/steel-burnishing-media.htm" target="_blank">http://www.steelmedia.com/steel-burnishing-media.htm</a>

Sample Time! :D

[johnn 99]

How about a BBQ rotiserie motor? You should be able to pick one up at the second hand store for a couple of bucks, and they plug into the wall. Also they have a nice steady slow rotation, and are built to handle a fairly heavy load. Hope this helps!

[The Great Milenko]

I was going to build a ball mill just like the one described by wouter visser, and I was going to use a motor from a fan, the motor would be durable enough, but could'nt I just mount the cannister with the media and the material to be milled straight onto were the fan blade was? I'd have it horizontal of course, and perhaps I'd have something to support the cannister at the other end as it is going to have a fair amount of lead balls in it after all, is there a reason why the motor and the milling cannister are'nt directly connected in wouter's method?
Sorry if these questions are blindingly obvious to everyone else, but I'm slow :rolleyes:

[VX]

I am in the process of building a ball mill. The 'jar' itself is a 5 inch diameter piece of PVC pipe, caped at one end with 18mm MDF, and filler around the edges.

I spent last night trying to find free media.
2 hours at the scrap yard acquiring the ball bearings from the CV joints off several cars.... that didn’t work (scrap yard closed and we had to leave, with nowhere near enough balls.)

So my next idea was to use something except steel. I had the idea of using glass marbles. I think that these will work and if they do it gives us a very cheap milling media (£2 for more than enough). I have tried to smash a marble and they're bloody invincible buggers! So I cant see any reason why they wont work..... As soon as I find a motor and test it out I’ll let you all know how it goes.

I'm making it to produce heigh grade BP, to make rocket engines.

<small>[ April 18, 2002, 08:37 AM: Message edited by: VX ]</small>

[The Great Milenko]

Yeah, I seriously doubt the likelyhood of me being able to find that many steel balls, so I was thinking that perhaps I could use lead balls? because they're even cheaper than marbles! But marbles would be my second choice if lead is no good, However I'm using my ball mill for making AL powder.

[VX]

I thought about lead balls, but decided against them because lead is very soft and I was not sure if they would deform. (Also because I couldn't find any!)

They would be no good for milling Al anyway because Al is harder than lead, so the Al would grind the lead. Especially if you intend to grind Al granules down to powder as I do.

[The Great Milenko]

No, I aim to grind down some AL foil sheets, I've heard that this produces a rather good AL powder, Do you think that the marbles would work for milling AL foil into powder?

[10fingers]

I think lead is too soft. It would rapidly wear away and you'd get a lot of lead in whatever you're grinding.
The glass marbles may work if they are heavy enough. What is the weight of glass in comparison to steel?
I know Pyrotek sells brass balls for milling but they are kind of expensive and I don't think they would work to well for aluminum.
My ball mill is 4 in diam. by 8 in. long. I have about 20 3/4 in. steel ball bearings in it. The rotation speed is about 120 revs per minute. It works excellent for powders and aluminum. You may want to have two drums, one for aluminum and one for powder since aluminum requires the modification I mentioned above.

[The Great Milenko]

Hmmm, well I'll have to keep looking for some steel ball bearings by the look of it, But would my idea of mounting the milling cannister directly onto the fan motor and dispensing with the wooden frame and the roller work?

[VX]

The marbles are lighter than an equivalent size steel BB but as I don't have any steel BB's I'll have to try them and see what happens. If they don’t work then I'll either go back to the scrap yard or try something new :p

Another thing that may be worth a try is to get the large ball bearing from inside a computer mouse, I just found out someone I know has quite a few old, broken ones.

10fingers, how much Al powder do you get from one batch?

[10fingers]

About 60 grams. If you try to put too much in there it takes way too long. I used shredded aluminum foil.
It was more of a test to see if it would work since it is easier for me to buy powdered aluminum.
A fan even on slowest speed will most probably need to be geared down. You need to figure out as best you can what the RPM is. If I remember right you want the milling drum to turn at 100 to 150 RPM.
Have you looked at the plans on Wouter's? You will save yourself a lot of headaches if you follow his a closely as you can.

[Zero]

Motors have always been the sticking point for me. I just burned out a motor that I thought would work, and now I'm fresh out of AC equipment. I'll see if I can get my hands on a garage door opener. That ought to drive a sizable mill.

Regardless, I got some brass coated lead balls from the local Sports Authority for use with muzzleloading rifles. The balls came in a blister pack of 25, and cost about three bucks for the lot. No age check, no nothing. I got about six packs. I figure I'll find other uses for th extras...

~Zero the Inestimable

[Anthony]

yeah, direct drive from a motor would be too fast. The jar would be like a centrifuge with everything stuck to the inside wall, rather than tumbling. It also put the motor under a higher load, making it more likely to burn out over time. Another consideration is that you've have all the weight of the jar on the motor's bearings, they're not intended to take that kind of radial loading and will fail over time.

My experience of milling Al foil with lead media is the media being plated by Al and increased by around 50% in size!

[10fingers]

Good point about the centrifugal force. A place to look for motors is an electronics surplus store. It doesn't have to be very big, maybe 1/10th HP for an average ball mill. In the city near me there are several surplus stores where you can get a suitable motor for around $5.00.
When ball milling aluminum I forgot to mention that you have to put about a half teaspoon of light oil in the drum to keep the aluminum from clumping together. You can rinse it off after milling with some solvent.

[The Great Milenko]

See, I told you it'd be something blindingly obvious. :rolleyes:
Ahhwell, I'm guessing that the motor in my fan is pretty durable, so I'll just make one like wouter's, thanks heaps for all the help :)

<small>[ April 19, 2002, 03:01 AM: Message edited by: The Great Milenko ]</small>

[Zero]

I just had a thought:

How much energy do you figure would be lost due to friction with a bike chain? I have bike parts all over the place. That could be a good way to gear down a fan motor or similar.

~Zero the Inestimable

[vulture]

If i'm correct a bike chain doesn't has much friction and good direct energy transfer. If the mill get's stuck for some reason, the chain will probably run off or break before the motor could get damaged.

[Anthony]

IIRC a good chain drive is 97 or 98% efficient.

I doubt the chain would save the motor, maybe a plain belt would, but a good bike chain will take quite a few horsepower without breaking.

[cracker]

Recently I purchased a 15lb Ball Mill from Firefox Enterprises. I use grade 100 Chrome Steel media.

I am very new to the Ball Milling process and am very much in the early learning stages. Yesterday I decided to Mill some rather large particles of Ammonium Chloride.

I opened my Mill today to find my nice "shinny" Chrome media, to be the color of an old penny, which has rubbed off and throughly colored the Chemical a nice rust color.

Obviously I should have used different media for milling this Particular Chemical.

Any input would be helpful.

Also does anyone know of a Milling Guide that would show what to Mill with what Media?

[DONMAN]

If any moisture got in there it might have catalyzed a replacement reaction with the chrome.

[cracker]

Yeah, thanks for your input DONMAN. There was definitely a little moisture, I had recently washed the Drum and Bearings.

[tmp]

Get some non-metallic, non-reactive media. Glass or ceramic media works
very well. You said that you were grinding NH4Cl. Compounds of ammonia
tend to interact with metals.

[DONMAN]

From what I have heard Ceramic media is the best.

[Cobalt.45]

Ceramic media has issues with "static" (for lack of a better term).

The issue of whether or not this electrical phenomena has contributed to accidents involving flammable comps is debated on various forums, like rec.pyrotechnics.

What is known, is that the ceramic media (some, not all?) will produce a "light show", if shaken up together in the dark. Some claim this is harmless phosphorescence, others are convinced that it will lead to dire consequences.

Lead isn't perfect- it erodes. Ceramic costs a lot and is really too light to mill effectively unless the milling time is increased. Steel sparks.

Brass would seem to be ideal, but is hard to come by and expensive when you do find it. Glass is light plus readily chips.

Lady Kate, (from wichatabuggywhip) advocates using lead, melted and poured into copper tubing. This is then cut into pieces and used to mill. Long, drawn out process.

Some claim good results from milling with quarters and nickles. Others swear by black powder gun balls, yet others like sling shot ammo from WalMart (3/8" and 1/4")

Myself, I use hardened lead.

[Bacon46]

I have been using 3/4" copper pipe filled with Bismuth for most of the ball milling that I do. The pipe will change colors with certain chemicals, but this patina usually washes off easily, and never has discolored the chemical being milled.

I don't cut the tube into small pieces as mentioned in Cobolt45's reply. I use from two to four pieces of pipe that are a couple of inches shorter than the drum. It works well and is quieter than balls. I have steel and aluminum pipe I use as well, depending on the chemical or composition I am milling.

Lead would work just as well, if not better, for filling the pipes. I just happen to have Bismuth on hand.

[Cobalt.45]

I use from two to four pieces of pipe that are a couple of inches shorter than the drum.
That's an interesting concept- to use the pipes the full length of the container.

As long as the pieces didn't wedge themselves solid some how, this seems to be a novel idea, and it would be quieter.

What size is your mill?

[Brisant]

Well, I'll dive in here since I've been milling stuff for a few years. A good ball mill can be had from The Chinese Tool Factory (AKA Harbor Freight) by website or local store. A single barrel is about $30, a double barrel is about $40, less when on sale, which is frequently. It is the identical mill sold by United Nuclear for $70, (but UN includes media.)
I made my media from wheel balance weights, a couple at a time by using a black powder rifle bullet mold. A beter mold can be had from Wolter pyro tools. If you don't want the bother of making your own media, PyroCreations.com had lead/antimony balls for $16/100 plus shipping. You CAN mill aluminum down to a single digit micron size, but it takes about a week. To avoid the pyrophoric problem, I mill Al or Mg 1 hour on 2 hours off using a 110 timer switch, $4 at K'mart. Just don't let it get hot and you'll be fine.

[grimreaper]

Automotive windscreen wiper motors might be worth a try as the drive for a small homemade ball mill.

They are high torque, low speed, cheap and readily available from auto dismantlers , some vehicles even have variable speed devices.

Most are 12 volt dc and come with a built in reduction gearbox, and would certainly run off of a domestic battery charger for extended periods.

[Bacon46]

That's an interesting concept- to use the pipes the full length of the container.

As long as the pieces didn't wedge themselves solid some how, this seems to be a novel idea, and it would be quieter.

What size is your mill?

It's a small homemade mill 14" long with a 4" ID. The most I grind at a time is 2 or 3 pounds depending on the chemical or composition.

The links below are to two images of the mill. It's made with 4" ABS pipe and a windshield washer motor. The pipes shown are 9" long. The tub is tilted toward the motor slightly to keep the material under the rods.

It really works well. I can mill most chemicals to a super fine, talcum powder like consistency in 2 to 4 hours.

http://good-times.webshots.com/photo/2368511310100688881UNxwxW

[Cobalt.45]

A good ball mill can be had from The Chinese Tool Factory (AKA Harbor Freight) The unit that you mention is the same one I use. It's adequate for smallish batches, and the price sure is right.

But I don't like the cheap plastic "sheaves" used on the HF mill, and the "O"-ring belts break at the drop of a hat.:p

I've posted previously on replacing the breakage prone origional belts with "O"-rings made from better material. Well,
since then, I found a belt originally made for a vacuum cleaner that has ended my problem with belts.

With a pancake fan and a thermal overload switch wired in, it's good to go.

I like the idea of a mill with more capacity and with a better drive system.
The two-barrel HF mill uses a "V"-belt; I don't know if the pulleys on it are still plastic or not.

It's a small homemade mill 14" long with a 4" ID. The most I grind at a time is 2 or 3 pounds depending on the chemical or composition. That has to be the simplest mill set-up yet! Except for the 12VDC requirement, which isn't really a hindrance, that idea is really good.:cool:

What is it that you've used as the "female" receiver attached to the wiper motor? And, what are the details of the barrel?

[tmp]

On the subject of milling media, there are many that can be improvised as
already discussed here. Glass media works for non-metallic substances that
aren't too hard. If you can't find something suitable from a vendor may I
recommend using kid's large glass marbles. Certainly, the potential for
contamination is extremely low.

[Alexires]

Personally, I use lead sinker weights (as in the fishing ones) they arent half bad I have found, but they certainly haven't been tested in prolonged use by myself.

I like the look of that Bacon46. I don't quite understand how things would get ground finely using that. Wouldn't the force be distrobuted to much for it to break apart the clumps of whatever you are milling? What do you normally mill in there? What consistancy do you start with?

Sorry for all the questions, but it certainly looks like a good setup and I'm trying to get my head around it.

[Bacon46]

What is it that you've used as the "female" receiver attached to the wiper motor? And, what are the details of the barrel?

A 4" ABS pipe cap.

The details for my Ball Mill where provided in the link in my previous post. Something must have gone wrong with that link. The link below is to a photo album of some of my pyrotechnic endeavors. On the second and third pages there are images of the actual mill, the details, and a video of it running.

I Wouldn't the force be distrobuted to much for it to break apart the clumps of whatever you are milling? What do you normally mill in there? What consistancy do you start with?

It actually works quite well. I can turn most chemicals and/or compositions to a very fine powder in two hours. If there are large (3cm+) hard chunks I will break them up a little, but for the most part I start with whatever size the material is when I get it. Compositions like BP I will mill for 12 hours or more to thoroughly combine the ingredients. Doing this dramatically improves the performance of BP.

In the video I am grinding Cl0H8 in the form of Moth Balls. For this I use 6 - 3/4-11 steel nuts for media to break up the balls. I could put them in a Zip-Lock bag, wrap that in a tee shirt and wack them on the ground a couple of times before I put them in the mill. It would be quiter than milling with steel nuts. Just lazy I guess!:D


http://good-times.webshots.com/album/558263114ucdJBC

[Zappa]

My ballmill works fine with glass marbles (about 3cm diameter) and an old windshild wipermotor from the junkyard, directly attatched to the drum. The motor is for 12V, but takes easily up to 18V without getting to hot. The drum is a 25cm joint for PVC-drainpipes, inclusive the caps in the same diameter. The sealings in the joint keep the dust inside. Total cost was less then 50 €.

[hst45]

I don't cut the tube into small pieces as mentioned in Cobolt45's reply. I use from two to four pieces of pipe that are a couple of inches shorter than the drum. It works well and is quieter than balls.
I remember seeing something about this. I believe it was in Von Maltitz's book on BP manufacture. IIRC DuPont used this concept, ie "Rod Mill" to grind their BP. Regular brass rod would seem a natural for this, as well as perhaps copper pipe filled with lead.

[Bacon46]

In the video I am grinding Cl0H8 in the form of Moth Balls. For this I use 6 - 3/4-11 steel nuts for media to break up the balls. I could put them in a Zip-Lock bag, wrap that in a tee shirt and wack them on the ground a couple of times before I put them in the mill. It would be quiter than milling with steel nuts. Just lazy I guess!:D

The steel nuts didn't work

I wound up beating the shit out of the moth balls with the Zip-Lock and tee shirt.:(

[cracker]

The steel nuts didn't work

I wound up beating the shit out of the moth balls with the Zip-Lock and tee shirt.:(

Because I was busy and working alot, I left my Naphthalene (Moth Balls) in a 15LB Ball Mill with 27/32" Steel Media for 5 days.

All it did is slightly reduce their size and strangely left almost no powder behind. I ended up using 3 Ziplock Freezer bags and a Rubber Mallet.

After this experience I will never put anything "Oily" in my Mill again at least not without a liner.
5 or 6 milling "batches" later the Drum still smells like Naphthalene.

[nbk2000]

Industry uses dry-ice pellets to ball mill 'mushy' materials, as the extreme cold makes the materials brittle enough to fracture under the impact of the milling media. :)

Were you getting clumps of napthelene, or were the moth-balls staying balls? It could simply be that you need to break 'em up a bit so they don't simply roll along with the media up the side of the drum.

[cracker]

They were just staying balls. I think that the "oily & sticky" texture of the Naphthalene and the pressure from the "tablets" being formed makes for a pretty dense product to Mill.

Breaking them up a little didn't seem to help much.

I am very greatfull for the dry ice "tip" though. That concept makes good sense. Infact it might have even helped in this case.

Although one would want to be sure they didn't use "to much" dry ice or enough to cause the rubber liner in the Mill to become brittle.

[Bacon46]

I won't ever mill napthalene again either. I'll use Cremora the next time I want a fireball.

Dry ice does sound llike a good idea for chemicals like Sr(NO2)2 that allways want to "Cake Up" in the drum. I have tried drying it in the oven before milling without much improvment, freezing it might do the trick. Maybe I could try packing the dry ice inside sections of pipe and adding it to the grinding media, three lead filled and two filled with dry ice.

My drum is small (176 ci / 2883 cc) and is almost air tight. Do you think there would be any issues with the buildup of gas pressure in the drum? If so; do you have any ideas for venting the gas without venting the chemical I'm milling?

[Frunk]

My drum is small (176 ci / 2883 cc) and is almost air tight. Do you think there would be any issues with the buildup of gas pressure in the drum? If so; do you have any ideas for venting the gas without venting the chemical I'm milling?

Ugh... ever heard about those CO2/Soda bottle noisemakers? It could very well do the same and spray whatever chemical you are milling all over the damn place.

[hydra]

Steel balls are by far the best.

If you don't have a good boneyard to get CV-joint balls from, then check with the local car-repair guys...most of them have a few old CV joints out back in the weeds that they forgot to take back for core-charge refund.

Also, if you have anyone in the area working on old heavy-equipment (i.e. dozers etc), they will likely have a few bad old 'final bearings' around. These are HUGE ball bearing races...and the balls are perfect for milling.

Motors: power-window motors and wiper motors from cars are already geared down, are fairly powerful, and can usually be had cheap or free. They'll easily run off a battery-charger; and it is easy to make a speed-control for them.

note: the window-motors are pretty powerful, but aren't really designed for continuous running; at least, not at full voltage/power. If you're cutting the voltage back to 6v (for example) for speed-control, then they'll likely be OK for continuous op.

Conversely, the wiper-motors -are- designed to run forever. I tend to use wiper-motors for anything that needs to run for hours.

AC gearmotors would be better where speed doesn't need to be controlled...but I live off-grid (no full-time AC power), so I tend to use a lot of DC stuff...lol...

[nbk2000]

A small hole drilled in the end cap would vent the CO2 pressure just fine.

You can expect a little bit of your product to be lost through the hole, but you can't risk pressure build-up, so no screens or filters in it, otherwise BOOM!

[cracker]

Perhaps a person could attach a Fermentation "Burp'er" to the vent hole.

This could help with avoiding contamination and loss of the Drums Chemical Contents.

[nbk2000]

A piece of flexible rubber hosing that was supported upright, and allowed to freely twist, would allow for venting while feeding any spill-over back into the drum.

[megalomania]

Why don't you dissolve the naphthalene in a solvent and recrystallize it to a easily crushed powder?

When I worked in a plastics lab I would cool samples of stripped wire (the insulation, not the metal) with liquid nitrogen so that the soft plastic could be ground up in a mill. It is a very effective technique.

[ChippedHammer]

Is the PVC pipe glue reactive with anything?

Reason I ask is because I decided to make a new mill, the local hardware joint only had pipe with one end threaded. I couldn't get a end cap that would slip over the pipe as the only thing they had was one that went inside the pipe (hard to explain but the pipe stayed the same diameter).

Which meant I had to use the PVC pipe glue, tried not to get to much inside but there is some left over.

Last thing I want is for something to react with it and start a fire.

I find marbles to work quite well with most softer materials.

[defiant]

Another venting technique is to turn off the mill and open the drum :o

With regards to the earlier discussion of the "ideal" media, 316 ball bearings have a lot of advantages. They're corrosion resistant, relatively heavy and hard, and readily available (ebay, etc.). 316 stainless also doesn't spark as readily as a carbon steel (but use lead, bronze, or monel as spark proof media).

The following links may also be of some interest:

http://www.pauloabbe.com/productLines/millingEquipment/ballmillhandbook.html

http://www.pauloabbe.com/productLines/millingEquipment/principlesofgrinding.html

[justme]

I have just uploaded a very good manual on building a high quality ball mill on a budget. This work is oriented specifically at pyrotechnics hobbiests, and is buildable by anyone who can read and possesses minimal mechanical and woodworking skills. The book contains formulas to calculate charge, rotational speed etc., which allows the builder to customize the project to his or her needs.

http://www.roguesci.org/theforum/showthread.php?t=5388&page=20

[ChippedHammer]

Cheers

My motor from a cordless screwdriver is on its last legs, I need a excuse to built something that doesn't look dodgy.

[Pb_Producer]

So after I did a little more research on this topic I’ve decided to invest in some brass balls for the media in my ball mill, I was kind-of restricted in what I could use. As most of the people here my main use for the media will be for black powder.

Of course steel balls can’t be use for black powder as they spark, and as we all know that’s bad.

Glass balls are cheap, but they chip and weight nothing.

Lead it ideal, except that it easily tarnishes and is also toxic.

Brass is the best choice as it doesn’t spark, isn’t toxic and weighs a good amount. The only down side is that it can’t be used for grinding chlorates, perchlorates and ammonium nitrate as they react to the copper in the brass. Brass has also been known to be quite pricey.

My question is; what size and how many should I use? I was thinking about 10-15 1 – 1 ½ inch balls, as they would crush a little harder and that would be splendid for the black powder quality. Any input on this would be great.

I also emailed about 10 companies trying to find the cheapest prices. When I get emailed back ill post the best company regarding price, incase anybody is interested in buying some.

[justme]

pb_Producer:

Download the RS file above and take a look at the discussion of different media characteristics. The file will also give you the math and properties required to efficiently run a ball mill. 10 or 15 inch and a half balls is so underloaded as to be virtually worthless.
I have a one gallon mill with half a gallon; maybe 20 or 30 pounds, of antimony hardened lead balls in it, and it runs efficiently. If you want to get the premier milling media, look to high alumina ceramic media, fill the mill jar half full, and run it at the correct speed.

Get the file!

[Pb_Producer]

I’ve given up on my search for brass balls as they are way to expensive for a simple ball mill and most of the companies are retards established in India.

Going back to the media type, would it be possible to use steel as media for black powder, I know it sparks but are they big enough to set off the whole mix and does 1/4" spark? Which steel sparks the least out of chrome, stainless or low carbon?

[nbk2000]

ANY spark can set off BP, and ball bearings make great anti-personnel fragments. ;)

As regards static electricity build-up, if your lifter bars were made of conductive metal, the bolts that pass through the PVC to hold the lifter bars in place, could in turn be connected to a metal strap that goes around the drum, and is connected to a ground by a drag chain.

[ChippedHammer]

Brass is damn expensive, best I've found is about $6US for 6 1/2 inch balls. I purchased 25 1/4" balls (small mill, only does 80gm max) and they work well. Still on the lookout for a powerful enough motor with a good duty cycle, been trawling markets and wreckers but cant find anything suitable.

http://cgi.ebay.com.au/Five-1-2-brass-bearing-balls_W0QQitemZ180111380045QQihZ008QQcategoryZ6160 3QQrdZ1QQcmdZViewItem
http://cgi.ebay.com.au/25-1-4-brass-bearing-balls_W0QQitemZ180111393379QQihZ008QQcategoryZ2642 0QQrdZ1QQcmdZViewItem

[Bacon46]

Still on the lookout for a powerful enough motor with a good duty cycle, been trawling markets and wreckers but cant find anything suitable.

This is very similar to the motor I use. They are strong and have a continuous duty cycle. A 12V / 1.5A wall transformer runs mine.

http://www.allelectronics.com/cgi-bin/item/DCM-249/400400/POWERFUL_WINDSHIELD_WIPER_MOTOR_.html

[justme]

Okay, I will digest the important basics of ball milling.

The rotational speed of the mill jar must provide for a cascading action which is a function of the angle of repose of the media. This angle is not dependent on the density of the media.

Obviously, the weight of the media is necessary so that there is sufficient "crushing" force for the material being milled. Any of the normal media, lead, ceramic or brass have sufficient density for the job. In milling metal powders, hardness of the media becomes more important, and ceramic is the preferred media type.

Along with rotational speed, media charge is the factor most overlooked by persons building mills, and should be equal to one half of the volume of the mill jar, no matter what the density or size of the media. This is what allows the media to assume the correct angle of repose and produce the cascading effect.

Along with media charge is the amount of material being milled. This must be equal to 25% of the jar's volume, or, enough material to fill the empty spaces between the balls, plus a little, since the balls are about 60% solid and 40% empty space. The rule of thumb for wet milling is to fill the jar to one ball diameter over the balls.

Never use steel, other than certain types of Stainless for milling a mixture or fine metal. Steel sparks, any spark can and will cause ignition, and that can be bad. Glass also sparks, and some types of ceramic. The safest media to use is antimony hardened lead, and if the mill is designed properly, will wear very little. Media can be any shape, and small cylinders are possibly the easiest to make. (cast them in tinfoil tubes)

Okay, there you have the basics, there is much more if you study.

[tintinteslacoil]

DON'T use lead balls! They coat the Al or Mg or whatever with Pb, and make it non-flammable. I have picked up plenty of ball bearings just lying around the road (sell some to Captain Queeg!!), or, you can buy 1/4"-3/8" slingshot ammo from K-Mart. The bigger, the better, though. Firefox or Skylighter sells 3/8" balls; also, some recommend Pb/Antimony balls as safe for Mg. You can borrow a ball mold from a black powder enthusiast, and make them out of the terminal posts of old car batteries. They will remain shiny, as opposed to pure Pb, and are much harder.

[PanMaster]

I tried grinding some aluminium foil with 340 1-1/16" chrome steel balls in a 275mm HDPE barrel until it cracked after forty minutes under the weight continually flexing the thin walls. The aluminium went everywhere, fine enough to coat hands with a greasy silver finish. It seems the problem is the container. Where can you get a very, very thick walled, ~275mm, perfectly round screw on lid sealed container? Something like this foreign companies design:
http://www.pyrosupplies.com/prod_img/full/d0fe804e9e00457adc35cce1e143ecb5/e017fb82c78a4a148c838a3163241755/12Tbar1_WinCE_.jpg

[Cobalt.45]

Anyone who is thinking about building a ball mill really needs to download the booklet justme has uploaded. It has ALL the info that is needed. It cost me ~$30 from Skylighter:(.

Even if you have a mill, chances are you can improve the performance by optimizing the charge size, media size and amount, the RPM for various diameter jars, etc.

If the RPM of the jar is correct, along with the other parameters, you will get very little erosion of lead media, or of the jar itself. Certainly not enough to make anything not burn:rolleyes:.

There's a guy on eBay selling used but still good ceramic media, 10 pounds for $28;) to your door. Another guy is selling new, $7/lb plus S&H.

[mtdawg]

I bought 5/8" and 3/4" brass hex/round cutoffs on eBay from one of the perennial metal suppliers there for very little $$$-he was able to pack about 45# into an $8.10 [at that time] USPS Priority box. An hour spent sawing them into 5/8"-3/4" lengths with a chopsaw and I had enough media for two 4" PVC milling jars or one 6". Not necessary to have perfectly round balls-using the correct milling speed for your jar size and proper media/material charge proportions as outlined in the book 'justme' uploaded to RS are much more important to efficient, uniform milling.

Glass marbles are known to spark on occasion-I'd never use them for anything other than single chemical milling for non-critical pyro mixes. Besides, do you really need small silicon chip impurities possibly sensitizing your mixes? Finely divided silicon [~325 mesh] is used in some e-match priming comps to raise flame temperature and provide a molten slag for more reliable ignition.

BTW, on the rec.pyro newsgroup there are 2 camps regarding the safety of ceramic milling media with spark-sensitive comps-one faction [including, I believe, the author of the aforementioned ballmilling book] maintains that ceramics ARE capable of sparking, even if only very rarely. "Are you feelin' lucky?"

A final note on ballmilling-many substances, including powdered metals [Mg, Al and Zr come to mind] and even charcoal can become pyrophoric during milling and be very dangerous if not handled correctly. The book gives that author's personal nightmare experience of milling extremely fine Mg with Cab-o-Sil.

A partial list of pyrophoric substances:

http://www.doctorfire.com/Pyrophoric.html

If you plan on doing much ball milling of metals, invest in a long extension cord, some nonsynthetic clothing and a Type D fire extinguisher-or at least a generous and handy supply of dry sand-I would NOT recommend using water on a mill jar half full of -1000 mesh Al which has spontaneously combusted...

[tintinteslacoil]

Pan Master;
The ball mill you want is a dead ringer to my old rock tumbler. Sorry, I cannot get a name off it anymore. The drum is rubber lined, that can probably be peeled out if desired. I have seen 1/8 h.p. universal motors like it uses at swap meeps. It runs cool, faily quietly, and I can get belts at vaccuum cleaner store.
I have been thuinking of using non-quartz-bearing metamorphic rocks toi tumble with. These are 3-4 Moh's hardness, and I'm going to try to get some tumbled ones at the next Gem and Mineral show:
Marble
Fluorite
Feldspar (fluorspar--used to MAKE ceramic)
I know there are a few more but I need to find my Rock Guide. The lack of Ingeous rocks, inclusions, or contast metamorphosis is ESSENTIAL to prevent getting quartz or something into the rocks to prevent sparks.

[Cobalt.45]

Where can you get a very, very thick walled, ~275mm, perfectly round screw on lid sealed container? Something like this foreign companies design
Except for the color, that is identical to the Thumblers Tumbler Model B.

The barrels are sold separately. I'd look in eBay, or gem and mineral supply houses.

It's said to hold ~15 pounds of material, but that may go out the window when properly charged to mill with, as opposed to tumble rocks.

It is MUCH cheaper to build one out of PVC:
A 2' piece of 4" ID PVC costs ~$5.00.
2, 4" "Test Plugs" cost ~$8.00.
All the above is sold at Home Depot, in the plumbing aisle.

A 5" or 6" jar would be better, but the cost goes up, and Home Depot doesn't sell 2' pieces any larger than 4" ID.

[PanMaster]

It is more expensive to build one out of PVC. 12" PVC pipe costs a bundle especially when the minimum length is several meters and it costs £380 per foot or something.

[SquirlHunterof09]

I know a good way to make a ball mill. Its really simple too. Get some plastic tubeing, a few different sized ones( I mean the width not length). You will need a metal rod, but I would be carful with that, you might be able to use a wooden one. I don't think a plastic rod will be strong enough.

Make a wood frame to fit the size of the pipe, also make some room to be able to remove the pipe, so make one piece of the wood frame removable that might work.

Then for the balls you could buy some soldering iron and get some play dough. Take the play dough and split it in half. flatten one piece of the play dough, not to much or the hot solder will go through it and burn whatever is on the bottom. Make some half round spots in the play dough. Then on the other side make it about the same size and put the other half of the half round spots in the exect same spots or you won't have a ball.

Make a line going down one side of the play dough to go through every round spot. Oh sorry I forgot to mention this, leave a little play dough over to cover the out side edges. Then after you cover the out side edges with the leftover, make sure it is really good because if you don't it will go right through and it won't turn out right.

Next hold the soldering iron over the play dough mold and heat it with a lighter or a tourch and melt it until you see it coming up close to the top. Go slow though because that is still a very small hole, Unless you make it kind of big. Next let it cool by putting it in some water. Wait a little bit so it gets cool enough to touch then take off the play dough mold. Remove the little extra lines you have and there you go the balls.Mostly lead , but a little tin but that won't have any effect I don't think.

Wow this is getting long.

Now on to the box. Do you remember what I said earlier, I hope you do because I'm not repeating it. Make one side a little bit long on the box to put a little motor. The motor you might just want to use a fan motor you might be able find a good cheap one on ebay, or you could use a drill but the fan lasts longer and doesn't need recharged. Make holes for the rods to come out of the wood. put some wheels on it. like some from sliding doors or from pulleys of some sort. Get a rope or you could use a big rubber band to run from the fan motor that you have mounted to the wood frame to the wheels on the rod.

If you need to slow it down then add one more rod beside that tube. You might even be able to have two different chemicals in two different tubes at once instead of having to wait two days to do two different chemicals you could do them both at once. On the rods you might want to add something to it to have the balls move a little more easier. Like another rod attached to that one,( by the way this will be inside of the tube that holds the balls and chemicals) or a piece of long plastic. Its just an idea but i have done this and it works really good. Well thats it.

I hope this wasn't too long.:D

[Cobalt.45]

Do you have any idea how many pounds of lead it takes to properly fill a 12" diameter by 16" long jar? Try more than 230 pounds!:rolleyes:

Or how much Al foil it would take to properly fill the jar?

The hexagonal Thumbler's container is not what you want for efficient milling, anyway- it's for rocks, and is more like a 6" or 8" jar, effectively.

[tmp]

Cobalt45, no argument there on the amont of lead needed. Poured as molten
metal, a cast of Pb would weigh 741 LBS in a 16" by 12" diameter drum. Hope
whoevers wants it this big has a very powerful electric motor.

[mtdawg]

A 5" or 6" jar would be better, but the cost goes up, and Home Depot doesn't sell 2' pieces any larger than 4" ID.

Drive by any new subdivision construction site and you'll be able to get 1'-4' scraps of 6", [even 8" and 10"] PVC "SDR" pipe for free. Any supply house that sells that sort of pipe locally will be happy to sell you the end caps and 6x4" adapters which can then be sealed off with the rubber "test caps/plugs" Cobalt already mentioned as being available at Home Depot.

The local Lowe's carries the SDR caps and adapters in 6" for $6-10- each, so my total investment in my three 6" mill jars has been just under $50, not counting the brass and lead media.

[Cobalt.45]

Three good jars for <$50.00- that's what I'm talking about!:D

PVC from work sites is definitely the way to go, if possible.

I don't know about Lowes, but Home Depot has a
line of fittings that are much less expensive than the standard fittings.

The end caps are flat, not rounded so the jar will stand by itself.;)

[jpsmith123]

Attached is a paper (Manufacturing of aluminum flake powder from foil scrap by dry ball milling process) others might find interesting.

[jpsmith123]

Has anyone used 1/4" diameter steel balls to grind anything, especially aluminum? I've found what seems to be a fairly good price (about $5 per lb) on stainless steel (type 304) balls, but the biggest size available seems to be 1/4". I wonder how efficient this size media would be?

[Charles Owlen Picket]

I've used a pretty large amount of various media in a variety of mall milling scenarios and have my personal favorites. ( I like 3/4" lead spheres) In most every application they beat out other material. Steel has it's place but the large lead balls seems fantastic. Your 1/4" just won't have the weight to grind Al....UNLESS your talking about taking a previous level of flake down a notch. Let's say you have 325 mesh and want to break it down to dark sub-sieve (2-12um). It may be OK for such a task; but you'll need a large amount of them. A pound of the 1/4 may work on a pound of 325 mesh paint grade but there are other complications in addition to retrieving them without making a huge mess :-)