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Ball Milling FAQ


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#1 Mumbles

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Posted 02 September 2009 - 09:01 PM

This is a commonly asked subject, so I thought I would provide an easily accessible central location. This is a simplified guide, and is in no mean meant to be all-inclusive.

Do I need a ball mill?

In a technical sense, you do not NEED a ball mill, but it's hard to progress too far in the hobby without one. They are by far the simplest, most cost effective, and least labor intensive methods to create black powder, and powder reasonable amounts of chemicals. They are also frequently used to create charcoal streamer compositions, such as tigertail (TT), Chrysanthemum 6 (C6), Chrysanthemum 8 (C8), and spider stars. When properly done, these are some of the most beautiful and elegant effects, along with being some of the simplest to create.

In doing research into black powder, you've probably come across several other methods.

Mortar and pestle – This can by all means be used to make serviceable compositions. It is potentially faster than a ball mill to make black powder, or other compositions. They are also useful to powder small amounts of chemicals. It has the disadvantage that it is extremely labor intensive relative to a ball mill.

CIA Method – This is done by rapidly precipitating out KNO3 with cold alcohol in the presence of charcoal and sulfur. This may be the fastest overall method to make black powder. It however is a rather expensive method with the rising costs of alcohol. It also requires the chemicals to still be finely powdered somehow.

There are numerous other methods I've seen over the years that are simply not safe. These include using a blender to mix the ingredients. Similarly coffee grinders have been proposed. There is a similar method currently being used to manufacture black powder for the military, but rest assured more precautions are taken that can be provided at home. There is one method I've seen proposed that utilizes a blender and alcohol or water slurry. I cannot comment on this, as not enough research has been done, but I however still would not suggest it.



Where can I purchase a ball mill?


Most people started with a rock tumbler. They are available at the lowest cost at Harbor Freight, running around $20 to $30. You will still need media. Lead shot is the most recommended media. It is cheap, and easily obtainable. It has a few disadvantages, namely the media will slowly wear away exposing both you, and the environment to lead. Brass has come under heavier use recently. It is harder to find in a ready to use form, and often is cut from longer rods, which require a few tools that one may not have on hand.

Rock tumbler: http://www.harborfre...temnumber=65838
Media: http://www.midwayusa...ctNumber=683574
(I chose the largest shot of the same price range.)

For approximately $45 you will have a functional ball mill and media, capable of creating BP in 8-12 hours. People have recommended going as long as 24 to 48 hours using the same setup. One will have to do some tests to determine when the quality of their BP is up to snuff. It has as much to do with the chemicals as it does with the machinery. I recommend taking a small sample every 4 hours for the first 12 hours, and then every 12 hours after that. Video taping the burn tests will give an easy way to compare.

Larger mill

As you advance in the hobby, a larger mill is often desired. Most are built to suit, but an appropriate mill can be purchased as well to an extent.

http://shop.ebay.com/hobfir/m.html

The 15lb mill will make approximately 1 kilo of composition in 4 hours. I will leave the media up to you. You will need approximately 150 ¾" x 1" cylinders. If using another size or shape, this corresponds with approximately 30lbs of lead, 18lbs of stainless steel, or 12lbs of ceramic.


What media should I use?

Good Media

I consider there to be only 3 generally acceptable media for live materials. Lead, which can be cast to suit, or purchased as large caliber shot. 50 caliber is good for most mills. Stainless steel can be purchased as rod, and cut into appropriate lengths. Brass can be treated in the same way. It'd encouraged to somehow clean up the ends with a grinding wheel to avoid tearing up your jar. Be sure to check incompatibilities of these medias still.

Questionable Media

Ceramic media - Ceramic CAN be ok. There is a firm, Coors-tek, that makes a non-sparking media for the explosives industry. If you are not 100% positive it came from this firm, and that it is designed to be non-sparking, save your ceramic for single chemicals. It is excellent for single chemicals actually.

Poor Media

Coinage - The money you're going to be LITERALLY putting into your mill will likely be enough to buy some lead shot. $10 of lead will be enough to fill a 3lb rock tumbler. I'm not positive on it's sparking or corrosion status either.

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.

Rocks – I think this should be self-explanatory.


Making your own ball mill

For the more mechanically inclined, this is generally the preferred approach. There really is no right or wrong way to make a mill. Dozens of designs can be found by looking at pictures of other mills. I hope to include some here in the near future to give you some ideas.

There are a few important things to include in a design:

Exclude the motor from the ball milling area.

There are a few reasons for this. It will allow the motor to be properly ventilated. It also prevents any sort of powders from getting into the motor in case of a spill.

A motor capable of turning a full load.

For a 1 kilo sized jar, this will corresponds to a ¼ to ½ HP motor. It's better to go too big than too small. Do research on the appropriate type of motors, and what will work for you. Be sure to check the voltage, number of phases, if it requires a starting capacitor, how is it meant to be attached, as well as how it is cooled. TEFC stands for totally enclosed fan cooled, which is probably ideal.

An appropriate pulley ratio to get an ideal speed.

Below is a RPM calculator. There is an excellent one on passfire as well, if you are a member. The one below will require two calculations. The first should be self-explanatory. The second one, treat the diameter of your driven shaft (including any rubber wrapping) as the drive pulley, the diameter of your jar as the driven pulley, and use the RPM of the first calculation, as the input RPM. Don't worry about the other stuff so much.

http://www.benchnote...ycalculator.htm

The rest of the materials

This is where the fun comes in. The rest is really up to you for design. Below are some helpful hints though.

Searching under the term "pulley" may yield aggravating experience when looking for supplies. The term "sheave" will hopefully give more fruitful results.

Idle rollers, such as used on conveyer belts, make excellent undriven shafts.

Pillow blocks are generally used to reduce friction, but I've seen people mount other sorts of bearing into wood, as OTC as skateboard bearing with success.

Some are fans of placing the motor on a hinge, and using gravity to tension the belt.

Use lift bars in your ball mill jar.


Why isn't my BP any good?

  • Are you using a ball mill?
  • Did you follow the above advice with regards to obtaining a mill?
  • Did you try milling for extended periods of time?
  • If you've wet and granulated/corned it, have you waited at least a week for it to dry?
If you've gotten this far without saying "no", it's probably your charcoal.
  • Ddizzle22 likes this
Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

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#2 seanh

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Posted 02 November 2009 - 02:00 PM

Quite helpful. Thanks :)

#3 GazaTech

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Posted 20 November 2009 - 10:54 PM

What kind of Charcoal do you recommend?



#4 Updup

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Posted 21 November 2009 - 08:17 PM

What kind of Charcoal do you recommend?


I assume you mean for making black powder? If that is indeed what you mean, willow charcoal is the "best" for black powder, however if you want the fastest wood ever balsa or tupilo works well.
Since this is a ballmilling thread, you will get more information if you serch for a charcoal thread (I'm sure there is one).

Here is a simple break down on what charcoal for what compo:
Black powder: Balsa, tupilo, willow, pine, and alder are recomended however you can make just about any wood work.
Streamer stars: Pine.
Fountain: Anything thats close (but not) to crap ;) .

Again, try serching the forum for a charcoal thread, you'll find one -_- . Good luck
"Pyro, and life, what's the difference again?"


#5 Mumbles

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Posted 21 November 2009 - 08:20 PM

I don't know if I would call willow the best, just the gold standard. What all the other charcoals are rated from. I'd suggest this thread. It's a good one.

http://www.apcforum....s...t=0&start=0
Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

The sky is my canvas, and I have 2,113 pounds of powdered paint in the workshop.

#6 dagabu

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Posted 22 November 2009 - 12:04 AM

I don't know if I would call willow the best, just the gold standard. What all the other charcoals are rated from. I'd suggest this thread. It's a good one.

http://www.apcforum....s...t=0&start=0


Wow, that's like saying that ball shells are the gold standard ;)

If the gold standard is Willow then what about Balsa? It is way more reactive then Willow. Taking a page from Schimizu, I would say that White Pine is the gold standard.

IMHO
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#7 AdmiralDonSnider

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Posted 22 November 2009 - 04:56 AM

If the gold standard is Willow then what about Balsa? It is way more reactive then Willow.



The fastest is not necessarily the best. Speed is just one aspect of good gunpowder. Consistency and precise burning is very important, too; that´s what commercial manufacturers such as GOEX focus at. What is more, turbocharged BP may burn too violent in many applications.

Other than that, why should people rely on an exotic material if trees like willow are growing in their backyard? Sure, they may only get 80% performance, but who cares if the powder does what it is expected to do?

#8 Arthur

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Posted 22 November 2009 - 06:59 AM

The whole of pyro tradition has grown up with charcoal typified by willow. Everything we regard as "usual" is based on willow charcoal. All the grain sizes and their uses, all the mortar lengths etc. even the shell casings are sized for a willow BP lift.

If you go for a faster BP for lift your tubes need to be stronger and your shell cases need to be stronger to withstand the lift.

A friend lifted some 3" shells with red gum bound BP by mistake - we didn't see the burst because it was too high!

Once you change the basics of pyro you have to accept that all the rest will change too, all the rules of thumb are no longer valid.

#9 jm82792

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Posted 22 November 2009 - 08:24 PM

What formula do I use to determine what sized brass balls I should use in a ball mill?
I would like to do a small DIY one since they are simple to do, especially since I want to only do 200G batches at a time.
On a side note are these good for ball mills ?
http://www.smallpart...CFQkwpAod-V1OlA

#10 dagabu

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Posted 22 November 2009 - 09:49 PM

The whole of pyro tradition has grown up with charcoal typified by willow. Everything we regard as "usual" is based on willow charcoal. All the grain sizes and their uses, all the mortar lengths etc. even the shell casings are sized for a willow BP lift.


I would love to see that qualified. If GOEX was using willow for their commercial BP, there would be no way we could touch it at home. Most commercial BP is made with a single species charcoal and none of them is Willow. I can qualify that via threads on Passfire of which there are at least two retired chemists that have worked for BP manufacturers.

The military 2Fa has a full history of all chems used in it all the way back to the mines and forest, it is all made from hard woods. That's not true of all military BP but it is of mine.

D
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#11 dagabu

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Posted 22 November 2009 - 09:52 PM

What formula do I use to determine what sized brass balls I should use in a ball mill?
I would like to do a small DIY one since they are simple to do, especially since I want to only do 200G batches at a time.
On a side note are these good for ball mills ?
http://www.smallpart...CFQkwpAod-V1OlA


I would pass on the brass and go for the SST balls. Check Amazon.com, the rule of thumb is 1:10 ratio, 6" diameter jar takes a .62 (5/8) round balls.

D
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#12 Mumbles

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Posted 22 November 2009 - 09:55 PM

Goex is said to use maple. I wouldn't go as far to say if Goex used willow, we couldn't touch it at home. Probably more accurately we couldn't just toss lumpy agricultural grade ingredients into a ball mill for a few hours and expect equal quality.
Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

The sky is my canvas, and I have 2,113 pounds of powdered paint in the workshop.

#13 jm82792

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Posted 23 November 2009 - 11:47 PM

I would pass on the brass and go for the SST balls. Check Amazon.com, the rule of thumb is 1:10 ratio, 6" diameter jar takes a .62 (5/8) round balls.

D

Does SST mean stainless steel ?

Sorry I don't know the abbreviations well,
I keep a reef aquarium, I'm a nano reefer
( a guy who keeps saltwater aquariums that's under 50 gallons(mine is 20 gallons),
with corals, fish and other invertebrates).
I know all the reefing abbreviations and stuff,
GFO = Granulated Ferric Oxide, LFS local fish store,\
Paly = Palythoa and a billion other ones but I'm new so i don't know many pyro ones yet :)

Edited by jm82792, 23 November 2009 - 11:50 PM.


#14 Ventsi

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Posted 13 December 2009 - 06:43 PM

Guys, I'm getting pretty desperate, I can not find a new belt for my HF tumbler. I'm going to try ACE today and Grainger tomorrow but hopes are low, I doubt I can find such a tiny belt with the right strength rating.

Any help here, I need a new belt yesterday so buying it online is not am option here.
Thanks.
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#15 firetech

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Posted 13 December 2009 - 08:06 PM

Ventsi, the tumbler itself is great. I have the 6-pounder but that damn belt breaks on me all the time. I've gone through the 3 they gave me. I've been using about 6 rubber bands for the past few runs, it works fine...maybe even better.

#16 pyrokid

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Posted 13 December 2009 - 09:55 PM

Guys, I'm getting pretty desperate, I can not find a new belt for my HF tumbler. I'm going to try ACE today and Grainger tomorrow but hopes are low, I doubt I can find such a tiny belt with the right strength rating.

Any help here, I need a new belt yesterday so buying it online is not am option here.
Thanks.


Can't help you locally, but pyrocreations carries 2 types of belts for the harbor freight mill.

check it out.

heavy duty belt

#17 dagabu

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Posted 13 December 2009 - 09:56 PM

Guys, I'm getting pretty desperate, I can not find a new belt for my HF tumbler. I'm going to try ACE today and Grainger tomorrow but hopes are low, I doubt I can find such a tiny belt with the right strength rating.

Any help here, I need a new belt yesterday so buying it online is not am option here.
Thanks.


Try a vacuum repair shop, they have round belts rated for long hours of use.

D
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#18 Mumbles

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Posted 13 December 2009 - 10:53 PM

I was able to replace the belt with an O-ring for a water purification system.
Just so you guys quit asking, here is the link to the old forum. http://www.xsorbit2....forum/index.cgi

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#19 scarbelly

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Posted 13 December 2009 - 11:44 PM

I have successfully used rubber bands as well. They wear out VERY fast though, so if you don't find something, you can use those, but get a belt from online asap. Be sure to check on it frequently to make sure it's still running also.
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#20 Ventsi

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Posted 20 January 2010 - 11:53 PM

I got some Vacuum belts a while back and have been cutting them into 3 rings each and they have been working perfectly, well almost...

I've got another problem , the belts start slipping if the load is too heavy and when I take them off there is a slippery white coating on them. This only starts to occur after 48+ hours of total running, and I think I know what the problem is, the cheap plastic pulleys are wearing off! Its the only logical option, when I take the belts off they have a slippery white powdery coating, and even though they are in perfect shape I have to clean/replace them often.

I was thinking of casting some aluminum pulley to replace the stock ones on the tumbler, yay or nay?

Also, another annoying thing was that the rubber rollers started slipping on the jar today, beats me how the hell that happened but I just slipped some surgical latex tubing and they are just fine now.

Edit; Man oh man do I love google!
http://www.backyardm...ngpulleys1.html

Edited by Ventsi, 21 January 2010 - 12:13 AM.

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