To ball mill or not to ball mill that is the question

[pcm81]

Good evening all. This is somewhat of a philosophical question and it boils down to: why would you ball mill your media vs buying online? I see some 3 micron powders (this is probably a limit of attainable by a hobbyist ballmiller) online for sub $20 per pound. Taking into account the time it takes to ball-mill macro scale metals to that level (more than 10 days in some cases) why would anyone not just buy the powders online? I am approaching my current ball-miling experiment as a learning of a new skill; however unless, i am missing something, i can't see any financial gain vs. just buying metal powders on Amazon or ebay.

 

Why not just buy powders, sieve them, and mix them via a 60 micron sieve rather than spending days milling? Once you add in your time and electricity cost, milling is bound to be more expansive that just buying the powder... What gives? I can see a use of a mill (ballmill or other) for a chemist who is trying to mill result of his chemical reaction etc, however for people making some form of product, (rockets, welding thermite, what ever else) wouldn't milling be a waste of time? I guess in some countries you can't legally buy micron sized powders, but so far i had no issues in US with amazon or ebay.

[MWJ]

I don't mill any metals. We mill compositions like black powder.

[Bobosan]

Good evening all. This is somewhat of a philosophical question and it boils down to: why would you ball mill your media vs buying online? I see some 3 micron powders (this is probably a limit of attainable by a hobbyist ballmiller) online for sub $20 per pound. Taking into account the time it takes to ball-mill macro scale metals to that level (more than 10 days in some cases) why would anyone not just buy the powders online? I am approaching my current ball-miling experiment as a learning of a new skill; however unless, i am missing something, i can't see any financial gain vs. just buying metal powders on Amazon or ebay.

 

Why not just buy powders, sieve them, and mix them via a 60 micron sieve rather than spending days milling? Once you add in your time and electricity cost, milling is bound to be more expansive that just buying the powder... What gives? I can see a use of a mill (ballmill or other) for a chemist who is trying to mill result of his chemical reaction etc, however for people making some form of product, (rockets, welding thermite, what ever else) wouldn't milling be a waste of time? I guess in some countries you can't legally buy micron sized powders, but so far i had no issues in US with amazon or ebay.

 

You are spot on, pcm81. Not only does it not make economical sense to mill metals to fine powder but a safety factor needs to be highly considered.

Edited March 3, 2015 by Bobosan

[FlaMtnBkr]

No one makes/mills their own dark aluminum which I'm assuming you are mainly talking about. Unless they can't get it, want to see if they can do it, or are compulsively paranoid. Which means a very small percentage of us.

 

Ball mills are mainly for making BP. And for breaking down granules and clumps in individual chemicals that didn't come as a powder. Very few people grind a powder with no palpable grainyness into a finer powder.

 

Is it a philosophical question or do you think most people are making their metal powders and want to know why? Because the bulk of us buy it. It appears you think everyone is making this stuff but you give some good reasons why we don't.

 

There are few things people can make cheaper than industry can.

 

Edit: correct auto correct

Edited March 3, 2015 by FlaMtnBkr

[pcm81]

Researching thermite (i am interested in thermite welding) i came across TONS of videos of people ballmilling metals, so i became curios about ball mills. Searching for ballmills i came across allot of videos of people making their own black powder and/or flash powders, rocket fuels etc. So naturally i became curios if i am missing something; it seemed like you can't really beat buying the ingredients to make the final product. I can see benefit of investing your time in home brewing a particular custom mixture of what ever (black powder, thermite or whatever else) to meet particular needs of your project, which might not be so well met by commercial product; however it seems that raw materials are just so much easier to buy online. So then i thought to myself, all these people wasting their time ball-milling materials can't be stupid. i must be missing something. May be the purity and quality of home milled stuff is still better than online sources... Hence the question here...

[braddsn]

pcm81, you will quickly find that in the pyro community, we don't mill metals. Trust me, it is a dangerous thing to do. Not to mention, there is really no good reason to do so. We mill things like charcoal, potassium nitrate, etc. Ball milling metals is asking for a disaster. People have been badly burned and almost killed milling metals. We buy our metals in whatever mesh and purity we need.

[MrB]

I think it should be said that we don't regularly ball mill metals.

 

I ball mill magnalium. The reason is quite simple. Most of what i use i don't need to be that fine, but i do need to reduce it from the rather large stuff i get when making it...

I do however use some of it for flash, but the coffee mills take it from rather small, to tiny, and it seams to work out for now.

Making my own magnalium lets me play around with the alloy, and it mills so fast it's not really a matter of cost.

B!

[Mumbles]

......

So then i thought to myself, all these people wasting their time ball-milling materials can't be stupid. i must be missing something. May be the purity and quality of home milled stuff is still better than online sources... Hence the question here...

 

 

The purity and quality of homemade powdered metals is generally significantly worse. I've rarely seen anyone providing any proof that they're attaining anything resembling commercially available products. There is a lot of "I milled it for 10 days, so it has to be single micron." type of statements out there and other totally unfounded beliefs/results. I bet if most people actually characterized their product there is at least 10-20% oxide, and not much finer than probably 30 microns.

 

Magnalium tends to be the main exception to people milling their own metals. It's brittle, and can be milled pretty easily. I find casting and making MgAl more useful for the less readily available coarse material though. If you really look into it, the people who tend to be milling their own flake aluminums and magnesium are usually people who are not well versed in this hobby, stupid, or often are approximately 15 years old and cannot figure out how to buy something from the numerous online vendors.

[pcm81]

Thank you all for knowledgeable, wise and well founded replies. Basically you all confirmed that what i was suspecting is indeed true and most likely i am not crazy.

[Mumbles]

Oh, we're all a little crazy.

[deer]

In a small country like mine, where such a hobby is somewhat exotic one can't find materials locally.

While it's fine when shopping online for electronics and such, with bulk materials, the weight adds up quite quickly and so does the shipping price.

Also, keep in mind that most shops in larger western countries ship only within themselves (US, UK, GER), it's the china that ships everywhere and once again they offer mostly cheap mainstream products.

 

E.g. it's much cheaper to buy 5kg of cat litter for 1.50Eur and mill it, than sending 300g from UK for 5 EUR + 9 EUR shipping. Also add in the risk of seizing your product because customs might go "what the powder.. I’ve never heard of bentonite better return it" or pay 40 EUR for insured parcel service.

 

Same goes for e.g. metallic tooling, or anything else more specific and heavy.

 

Edit: typo.

Edited April 24, 2015 by deer

[Arthur]

Suppliers for craft pottery can sometimes have things we want, in fair sized packets, and in your own country. They genuinely ship it as "Pottery Glaze" which attracts no attention.