Safety of Alumina milling media

[AzoMittle]

http://www.amateurpyro.com/forums/topic/11732-ball-mill-safety-discussion-part-2/

 

Done.

 

Now please, stop the Mean Girls-esque cat fighting and name calling, I don't see how my profile has any bearing on this discussion, if I were edit it to say "Licensed Display Operator" how does that help contribute to anything here? It doesn't, and I'm not claiming to be. Anyone can edit/post what they want, and if that is nothing (like your profile Lloyd) then great, if they want to fill out every detail, then great.

 

I'm just asking everybody to play nice, stay relevant, and if you have an global unbending rule (from ANYONE involved) then to back it up.

[Mumbles]

Here are the ceramic related ball mill accidents I'm familiar with, plus one more. All with publicly viewable links.

 

Gary Smith: Was using large ceramic media outdoors in a greenhouse. Said it was large mentos shaped ceramic media (~1.5") obtained through the FPAG. I believe this media was second hand, and of an unknown composition. Gary also utilized large lift bars as can be seen from the images, and stated that the mill was undercharged. There was also some believe discussed on passfire that this was actually the result of a leaking jar which allowed the motor to ignite BP. His motor was a brushed DC variety. Contamination with metallic fragments was also not ruled out.

 

http://www.amateurpyro.com/forums/topic/4605-ball-mill-explosion/

 

There were several sources of potential ignition in this case, and I don't believe any single source was ever pinned down.

 

Verdict: Unclear whether alumina was at fault, or if a proper charge, lift bar, and known media composition would have prevented anything.

 

A member here named BurritoBandito:

http://www.amateurpyro.com/forums/topic/9798-ball-mill-explosion/

 

Exploded while the jar was being shaken by hand. The cause was likely pinpointed to use of glass marbles as media. Not exactly ceramic, but in the same vein.

 

Avidus:

http://www.amateurpyro.com/forums/topic/11672-ball-mill-exploded/

 

Using large alumina media on a sensitive mixture. There is some controversy as to the true events and if he was bullshitting the whole ordeal. Regardless, it can be assumed that the composition is the biggest factor should it be true or partly true.

 

Dave:

http://www.amateurpyro.com/forums/topic/8580-someone-in-mn-had-a-booboo/page-1

 

To the best of my knowledge no cause was ever determined. There was little information disseminated about this one due to potential legal issues. A cement mixer was being used as a ball mill using large ceramic media. It was turned on to empty, said BP was ignited causing severe injuries.

 

Friend of Lloyds:

https://groups.google.com/forum/#!searchin/rec.pyrotechnics/ball$20mill$20magnesium/rec.pyrotechnics/RQtlrAbYG8Y/82z2eTbtb9wJ

 

Was milling a mixture of potassium perchlorate, Sb2S3, and cabosil. The ratio will ignite, but not sustain combustion. Ignition happened when pouring dirty media back into jar. Full ignition while using 302 SS media. Potential small ignition while using ceramic media. No size, media composition, product ratios, or media history noted.

 

Igntions while pouring dirty media back into a jar have been noted before by Bob Forward (Mg + Cabosil with 1" chrome steel balls), and I believe Lloyd himself had something similar happen though I cannot find the details at the moment though it involved Mg + Cabosil as well

 

 

These are the facts to the best of my knowledge. BurittoBandito's is the only one with a definitive cause. The rest are unclear and offer no proof one way or another as to the safety in my view. I'd be happy to be filled in on any other accidents involving ceramic or alumina media, particularly if they have a more defined ignition source. It would seem the clearest lesson is that hard media involved in large drops or violent shaking utilizing undercharged loads or dirty media is the most dangerous operation.

 

This lends some credence to Lloyd's suggestion that impact can cause accident regardless of sparking. All of the accidents noted above all involved larger than normal drops or forces than would be encountered during typical ball milling. Gary's is the only one that seemed to be possible under normal(ish) conditions. I'm not including Avidus in this statement, because there are so many issues with that particular incident, that I debated even including it.

[lloyd]

I don't know of all the instances (although I probably have records of them <G>), but you're right about that last point:

 

Long drops with under-charged jars can exacerbate the danger.

 

There are published ratios...

 

Lloyd

[DavidF]

I've milled plenty of black powder with (high alumina)ceramic media, and never had an accident. That said, the media, which I suspect was factory seconds, started to degrade. The surfaces developed spots, which turned into craters. Where did the material go? I stopped using it immediately. I think the damage was caused by milling charcoal by itself, which is similar to under-charging. The media can easily clack together- with BP, not so much. I don't think there is any harm in repeating this.

 

I don't there is any harm in also repeating that all my greenhouse grade potassium nitrate that I've screened has small rocks in it. One batch had a rock the size of a pea. If black powder was being milled with this hard igneous-looking rock in it, maybe it could go boom. My guess is that the likelihood would be much greater with hard media like ceramic, and less likely with media like lead or brass.

 

When I worked at an aluminum anodizing plant, we cut parts with radial arm saws. The material was almost always cut before anodizing. Sometimes though, we had to cut parts down after anodizing. Cutting anodized material made sparks every time. The anodic film was maybe 10 microns thick. The film is made of aluminum oxide, aka alumina.

 

Since the ceramic media degraded after time, was extremely hard, and was the least efficient of media I have tried, I choose to no longer use it.

 

You can completely eliminate the ball-milling of 'complete' black powder, but then the discussion shifts to the dangers of screen-mixing. In my opinion, making fireworks is inherently dangerous. Maybe I'm not safer by not using ceramic, but I feel better thinking I am.

[lloyd]

Hmmm... Azo, although I applaud your effort, "moving" the thread seems to have had little effect.

 

<shrug>

Lloyd

[Mumbles]

What sort of effect were you expecting? This is now a different thread than before. The previous one was mostly this conversation, so it may not have seemed obvious.

 

I still have to merge over a couple of posts from the thread Azomittle made. I didn't notice it when I split everything apart this afternoon, and got busy at work and couldn't finish everything.

[AzoMittle]

-shrug- As long as we aren't hijacking the poor new guys thread about "how do I burst 1" shells" all is swell by me.

 

A big thank you to Mumbles for dissecting and merging those threads; and a second big thank you to Mumbles for posting those incidents. Thank you to everyone else for getting involved and discussing this, it's interesting stuff.

 

Mumbles, if you have the time would you mind deleting that thread I started? Seems it won't be necessary.

[stix]

Lloyd: "moving" the thread seems to have had little effect.

Mumbles: "What sort of effect were you expecting?"

 

Hey guys, that's great! Having read the context, I'm still laughing

 

Thanks to those involved, it's good that this part of the original thread was moved and used. As Azo rightly pointed out "hijacking a new guys thread" is not on - an old guys thread?, well yeah, perhaps.

 

This "ain't no karaoke bar" where one can simply walk off to the bar for another drink if you don't like the singing. This is about safety.

 

Lloyd, don't be disappointed, I'll say that this thread HAS actually had some effect! It has reminded me of why I should not be using alumina ceramic media. I have a modest 1ltr ball mill and have only milled bp a few times (100gms) at a time. Small amounts so perhaps no big deal.

 

One option is using brass rod slugs - I just haven't got around to it yet and I don't make big quantitties.

 

 

[lloyd]

My "little effect" post had to do with the fact that the 'hijacking' was still continuing over there, rather than being politely moved to this thread.

 

I agree that it wasn't in concert with the original subject line.

 

Lloyd

[stix]

We've all done it. Validation for ourselves rather than listening to others - or should I say, forgetting or disregarding the original posters query.

 

Regardless of our knowledge, sometimes gentle persuasion is more effective than just pushing a point forward (whether true, valid or not). It's also about "tone of words" and it's always difficult because we can't actually 'hear' the tone of the recipients voice, so we have no way to react with sensibility.

 

Actually, I think I've just done it again

 

[EDIT] Of course there are always people who just don't/won't see reason.

Edited June 9, 2016 by stix

[WindowLicka]

Azo,

I have no ability to move this discussion. Do you? If so, please do.

 

There are numerous examples of mill explosions vividly depicted on the web, and most-often with good descriptions of what they were milling and with what media at the time.

 

I'm not inclined to go to the trouble of looking them up and posting links, when anybody can do that for themselves. I've been doing this since 1963. I've read of many milling accidents in that time. But we didn't start to actually DOCUMENT them until the "internet age".

 

This isn't a matter of 'opinion' in the pyrotechnic community... but perhaps you're not part of that group. Listing your bio information:

 

• Gender:Male
• Location:West Coast
• Interests:Bicycling, Algorithms/Data Structures, & Cooking

NOPE... nothin' about pyro there! AND living in an area where most any pyro activity would get the law on you in seconds!

 

We have a number of folks who've had anything from property damage to physical injury from exploding mills using high-alumina media.

 

Please... DO move this discussion to a new thread, Azo.

 

LLoyd

I can attest to the west coast being just plain anal towards any pyro activity. For gods sakes ground blooming flowers, sparklers and of course anything that becomes airborne has been banned. Safe and sane consumer fireworks around the 4th are an overpriced joke.

 

Thankfully country living and private property keeps accidental property damage to neighbors stuff a non-issue. For me anyways.

[MrB]

But I don't lie to folks... there's nothing in it for me OR them!

 

 

Pretty much my point, right there.

 

 

Tip for future post...

 

Oh I was under the impression alumina media had a potential a sparking hazard. Thank you for correcting me on that.

 

Feel free to copy and paste that.

 

 

Now look who comes of as a bit on an arse. Bottom line is that you are wrong. Since you have no idea what the purity of the media is, or what it's been laced with through it's earlier use, there is simply no way that you can say it's non-sparking. It's your life, and i can't be bothered with laying sleepless over how you handle it, but you should be aware of the fact that mills have blown up when milling BP with ceramic media,

 

I've seen from a few sources that some stainless steel is supposed to be non-sparking?

 

 

There is so much to the field, but yeah, your right. All steel will, at some point, spark. But then there is the temperature of the spark to account for, where ceramics, and some steels will most definitely throw sparks capable of setting of BP, but others shoot sparks that just doesn't have enough energy to light anything on fire. (Not that i'd like to stake my life on that) Regardless, i don't use stainless steel for compositions, i pretty much only mill magnalium with it.

Speaking of stainless, i'm in the process of having a mate cut up more square rod for me, since the media i got has been so worn it's no longer as effective. I'm debating with my self if i should start over with all new cubes, or mix new with old media. Oh well.

B!

[stix]

I thought I should point out why "I" use alumina ceramic media.

 

I'm milling ingredients on a very small scale (1ltr drum volume - approx. 115mm or 4.5" diameter). I use 1/2 inch media, and the "drop" would be less than half the diameter, so I'm not concerned about "sparks" or "heat" related ignition, but it's always in the back of my mind.

 

I don't mill much black powder - I'm into sugar rockets. Making bp (and other pyro activities) is a "calculated risk" based on knowledge. For what I do, based on my limited knowledge, the risk is small.

 

However, I wouldn't use ceramic media on a larger scale, unless I knew exactly what it was made of.

Edited June 15, 2016 by stix

[CrossOut]

If there is anything I've learned from working it is that time spend doing something DOES NOT mean you are good at it Or Knowledgeable about its subject matter. It only means you did it for a long time. In fact for most people doing things for a long time can bring a lot of issues to the table such as confirmation bias or placebo / negative placebo effects. I've found that the only case which doing something for a long time proved to be helpful is when the person is consistent in being intellectually engaged on the subject matter with an open mind.

 

I'm not sure why people feel the need discredit others or belittle them. Especially when they need to resort to something as petty as typo's or Profile information. As far as I'm concerned If they need to resort to that you've already discredited their selves are have shown they are otherwise incapable of engaging in intellectual conversation.. The forum is here to discuss topics not argue and banter like children. So If you are having an inferiority complex and feel the need to resort to petty argument tactics please exclude yourself from the topic and come back when you can control your emotions to engage proper discussion. Otherwise it only makes you look childish and makes the forum look bad.

 

But i digress....

 

High chromium Stainless steels are known to be non sparking. Industrial standards classify the material (in several different compositions) to be as such. That said, Most materials will react and produce sparks when in small enough particle sizes especially when heat is involved. Several hard materials will exhibit this when sheer or high impact forces cause the material to fracture into small fragments this can be observed when grinding or crushing the material.. Examples of non sparking materials which have this affect are Magnesium, Aluminum, Titanium, and as discussed stainless steel. In the case of stainless steel bearings it takes a considerable amount of force to cause this effect. I want to emphasize that this is a product of reactivity which few materials are exempt from.

I have noticed a trend in non sparking materials. That is, that the material is hard enough without being brittle such that it is difficult to break said material. This is the case for high alumina Media and stainless steel. The other Trend is that the material, while being hard, is malleable. This is the cause for aluminum, magnesium, and lead. Most of these materials are known to being Very Reactive. But these properties help to prevent reactions from occurring or producing a spark. Lead has the bonus property of being nonreactive which lends way to being truly non sparking. Alumina also has the property of being non reactive Tho there are other ingredients in the media.

 

If anyone has a high strength hydraulic press and some alumina media Please press one till it breaks and see if it sparks for me. Im interested in the results as this is a test i have yet to preform.. I will say this, grinding it with a grinder produces few or no sparks at all depended on the grinding material used.

Thank you Mumbles for posting known issues with said media or Ball Mil Accidents. Although alumina media may have been present in a few of those i agree with you in that it is not likely to not have been the cause.. The only incident which is unconfirmed is Dave's. That said there are many other factors which could have played a role. The cement mixer for example.. Unless he lined it with something, Mixers are generally made of steel.which we know about the properties of steel.

 

I have no doubts that impact ignitions are a major issue. Impact and press tests are a standard in testing reactivity of explosives and other flammables. However as I said before no media is exempt from this issue as care when handling of the ball mill should be stressed more than it is..

 

All that said, I am still going to hold my position on the topic of Alumina Media being safe for use in ball mills.. Tho I am still open to discuss evidence which prove otherwise.

 

Stix,

I dont see an issue with using Brass slugs other than being expensive! i would like to recommend rounding the edges tho.

MrB,

Im not Wrong.

 

I Never once said buy alumina media and start using it.. There are ways to test your alumina media as well as sources which sell said media with known composition information. In fact i stressed testing it first as i did with mine. As Mumbles said, Alumina media by definition has high alumina content which is safe (as i have shown evidence for and have yet to see definitive evidence against)

 

Your argument of uncertainty does not make sense. That is like saying (hypothetically) That you replaced the spark plugs in your car with "platinum plugs" but were not really platinum only mislabeled.. Your car did not work after installing said plugs.. According to your argument, Platinum Plugs dont work as proven by this event. When in actuality the event provides no evidence to support either side of the argument because platinum plugs were not involved in the experiment.

 

If the seller sells media labeled as "Alumina" that is not alumina then that was their mistake for listing it as such and the buyer's for not testing. in either case it is not an argument for or against alumina media because alumina media was not used.

Edited June 17, 2016 by CrossOut

[MrB]

MrB,

Im not Wrong.

 

I Never once said buy alumina media and start using it.. There are ways to test your alumina media as well as sources which sell said media with known composition information. In fact i stressed testing it first as i did with mine. As Mumbles said, Alumina media by definition has high alumina content which is safe (as i have shown evidence for and have yet to see definitive evidence against)

 

Your argument of uncertainty does not make sense. That is like saying (hypothetically) That you replaced the spark plugs in your car with "platinum plugs" but were not really platinum only mislabeled.. Your car did not work after installing said plugs.. According to your argument, Platinum Plugs dont work as proven by this event. When in actuality the event provides no evidence to support either side of the argument because platinum plugs were not involved in the experiment.

 

If the seller sells media labeled as "Alumina" that is not alumina then that was their mistake for listing it as such and the buyer's for not testing. in either case it is not an argument for or against alumina media because alumina media was not used.

 

You are wrong. Either that, or, your using a language that has no counterpart anywhere else in the world. Ceramic media isn't pure anything, but a mix of oxides, and depending on which, you get different properties. On top of that, there is always the purity issue. Even if a media is sold as Al₂O₃ media, you can still get anywhere from 85, to 99.99% pure stuff, that is 100% according to the manufacturers specs. Top that of with the fact that media is created with a number of different oxide-mixes as a base, doped with a bunch of different things, to create media variations for very different workloads, and all sold as, correctly, "Al₂O₃ media" as long as the bulk of it is Al₂O₃... Well, lets just say that there is no way you can fault the seller for stating that it is "Alumina media" and yet pretty much a unknown what properties it has, sparking, or not.

 

In plain english that means, you cant ever say, for certain, that any second had bought ceramic milling media, labeled as "alumina media" is safe for use with BP. And that means you are for all intents and purposes, wrong.

Since most ceramic media is non-sparking, it's "probably safe", in that regard, but "probably safe" isn't something i'd bet someone elses life on.

B!

[CrossOut]

You miss the point where you can test your media to be certain of its non sparking properties and i have yet to see any articles of incidences which show alumina media was the direct cause. Yes, I know that just because it has yet to happened does not mean it cant happen. but i will still argue that records dictate it's safety backed by its physical properties of properly tested and used alumina media.

 

additionally if you want to regard "probably safe" as not being good enough for pyro you better toss the idea of using a ball mill for BP manufacture out of the window as it is probably one of the the least safe commonly used methods of manufacturing BP.

 

Industry standards in china require the use of a roller mill which motion and friction is kept at a minimum and the use ball mills are prohibited for BP production.

[MrB]

 

You miss the point where you can test your media to be certain of its non sparking properties

 

 

No, i just don't agree with you on that "testing" can be done in a meaningful way, that will provide results accurate enough to live with.

 

 

 

Yes, I know that just because it has yet to happened does not mean it cant happen. but i will still argue that records dictate it's safety backed by its physical properties of properly tested and used alumina media.

 

Great, then we can end this. All i ever was against was the "fact" you provided, that ceramic media was inherently none-sparking, even if limited to "mostly" Al₂O₃ media variants.

 

additionally if you want to regard "probably safe" as not being good enough for pyro you better toss the idea of using a ball mill for BP manufacture out of the window as it is probably one of the the least safe commonly used methods of manufacturing BP.

 

 

Again, i have no problem with people using what ever they want, i just don't agree with the "fact" you provided. Encouraging use of ceramic media for milling BP may or may not be a good idea. I use lead, and recommend it, others use ceramic, and recommend it. But any recommendation should come with full disclosure. Ceramic media can only be considered non-sparking, if the manufacturer says it is, and provides the specs on the media. Second hand media is at best a guess as to what it was to start with, and what it has been used for since then. To some extent it can be cleaned, but your still in the unknown where it comes to it's sparking properties. Recommend a testing procedure that you think is good enough to provide the test results you feel comfortable enough to risk someone elses life on, and let them make the call them self, and i'll be fine with your recommendation for ceramic media, but stating as a fact that Al₂O₃ media is non-sparking, and i have to disagree.

I was pretty clear with this early on:

 

 

It's a simple fact, "Ceramic" alumina media has been in BP mill detonation, where as other, known not to spark, media hasn't. It's still generally considered a "safe enough" media, IF you can confirm that the manufacturer claims it's none-sparking. Which, point made here, not all media are. Second hand media? All bets are off. You have no idea what the specifications for the media was when it was brand new, and you have at best a vague idea what it's been used to mil since then.

 

 

 

We are all involved with a hobby that can quite easily kill us, or someone else. Stating false facts, isn't going to help us live longer.

B!

Edited June 19, 2016 by MrB

[CrossOut]

You have yet to provide any "facts" against my argument. Only conjecture. The only facts which have been brought up are by yours truly.

 

You argue that testing can not be done in a meaningful way which can produce reliable results? Seriously? If a guy can't preform reliable tests then he probably shouldn't be a pyro. The whole process of being a pyro relies on on testing, research, and improvement. That is why we are on this forum to ask questions, find answers, and share data.. I realize there are several who shouldn't be a pyro but now you are belittling the entire community. Honestly this is the basic scientific method! I'm sorry if you can't devise a method which can yield reliable data but don't assume others can't.

 

You seem to be using your argument against you're self now. I never once said the media was 100% safe. I simply recommended it. Stating that it is a commonly used non sparking media and is safe to use. Just as many have repeated the same for other varieties of media.

 

And for good sake stop saying ceramic media.. my argument was never about general ceramic media but specifically alumina media. (Its on the forum topic) Yes there is a difference and yes it is just as safe to use as lead When handled properly. If you disagree show me the data. Please find me irrefutable evidence of a high alumina media which produces sparks. I'm asking you to PROVE me wrong not post another argument about your opinion. So far all I've heard is the the words "false" and "wrong". No data, no evidence,only conjecture.

Edited June 20, 2016 by CrossOut

[MrB]

 

You have yet to provide any "facts" against my argument. Only conjecture. The only facts which have been brought up are by yours truly.

 

 

I don't really have to. You stated, as a fact, that Al₂O₃ media is non-sparking. It's not, and if anyone has to "prove" anything, then that is you. It's your "fact".

 

 

And for good sake stop saying ceramic media..

 

 

Why? It's the correct term. You want to be more specific, say Al₂O₃- or Aluminum Oxide- based ceramic media.

 

You argue that testing can not be done in a meaningful way which can produce reliable results? Seriously? If a guy can't preform reliable tests then he probably shouldn't be a pyro. The whole process of being a pyro relies on on testing, research, and improvement. That is why we are on this forum to ask questions, find answers, and share data.. I realize there are several who shouldn't be a pyro but now you are belittling the entire community. Honestly this is the basic scientific method! I'm sorry if you can't devise a method which can yield reliable data but don't assume others can't.

 

 

Right. Lets try reading what i said, and in the context i said it? Since a spark capable of ignition doesn't have to be possible to see with the naked eye, for a number of reasons, you just cant reliably test for it in a improvised environment. It has nothing to do with the scientific method, or the average pyro's ability.

B!

[stix]

People take a stance and then don't easily want to move from it, but facts are facts - right?

 

Surely it can be agreed upon that if you aren't sure of the quality and properties of your media, then it should be viewed as suspect.

 

There are relevant points from all sides that I agree with. I suggest that real tests need to be done using various media. I'm surprised that this sort of definitive testing, rather than anecdotal, has not been done before.

 

A relatively simple testing apparatus would be to swing from a pivot point (like a pendulum) various media smashing into each other with a bp coated substrate between. Start with the most likely (sparking steel, glass etc) then work it up from there. If it doesn't produce results (ignite) then go Mythbusters style and amp it up - flash perhaps?

 

It would also be useful and interesting to know the statistics related ball mill accidents using "non-ceramic" media.

 

I think there's something there for everyone if you look for it.

 

 

[otto]

Surely it can be agreed upon that if you aren't sure of the quality and properties of your media, then it should be viewed as suspect.

 

 

I'd say that's great advice. I just bought into a good amount of zirc-M media that is generally accepted as safe from a sparking perspective. Since it was used I figured it required a thorough washing before my use. Once washed and dried I picked through the pile after finding a heavily rusted piece. I found another dozen or so of those AND what appeared to be a steel BB.

 

Imagine the issue that might have caused......

[DavidF]

Crossout- respectfully- I don't think you are looking at this the right way. Even if you 'prove' to yourself that high alumina media is safe, what then? Will you ballmill black powder in your shed or basement, because it is safe? I'm just asking. I ballmilled BP in my shed, 2X750 gram loads. I thought I was being pretty safe. But when I made a 100 gram maroon with the mill dust, my attitude changed! I then realized that if my mill went BOOM for any reason at all, it would have destroyed the shed.

 

All black powder milling should be done with the assumption that the mill will explode. An unexpected mill explosion could ruin your life or kill somebody. Think of it this way: black powder plants and fireworks factories explode fairly often. These are people that know more than we do (at least more than I do)and they still have explosions. That's why there is only one black powder factory left in the whole US.

 

Lead is known to be non-sparking, and it is not hard. Would it be safe to mill with lead with no barricade? I certainly wouldn't do it. A bit of steel in the charcoal, rocks in the saltpetre or sulfur, dirt, there are just too many things to consider to say that ballmilling black powder is safe. Sure, it's safe. Right up until the second that it isn't.

 

I have been working on alternative methods for making black powder. It's certainly not everybody's cup of tea, but I use very small 304 SS media to mill my charcoal to a degree of fineness that is impossible with any other media. Yes this is a bold statement. I have milled charcoal and black powder with ceramic (high alumina), brass, lead, and stainless steel.

 

My tests have shown me that I can make screen-mixed black powder that rivals most milled powder. Also, in apples to apples comparisons, my home powder beat Goex. When I say 'apples to apples', I mean that my powder was pressed into pucks of a density of +1.8g/cc. It was then corned and graded to size. When used to launch baseballs, 10 grams of my powder (+-.01 gram) gave a flight time of 11 seconds. 10 grams of Goex gave 10 seconds. My 2FA sized grains tied with Goex 1Fg. 1Fg is the coarsest I can get up here.

 

I'm in the early stages of my testing at this point. I've already tested my powder in end burners, nozzleless rockets, and now with baseballs. Next will be with meal-coated rice hulls. I'm working on reducing the 'Yeah buts'. I also plan to use the same media in a modified Lortone mill to see how close I get to the more than acceptable performance I already enjoy.

 

Just another way to skin the cat. Don't flame me, BP millers! Almost all of you will never have a mill explosion

[redbullzuiper]

We are now 6/7 years later. I had good fun reading this topic.

 

I respect both parties in this and also CrossOut for his input. Although at some point people bacame a little childish towards each other.

 

The fun thing is, crossout was pretty much right about alot. Many, really many use ceramic and spark resistant steel as milling media these days.

 

Lots of new topics and tests have been opened and conducted in those years

Its good to have such discussion, as years afterwards you can still read the debate