29 replies to this topic

[pyrotechnist]

My mum has one of them exercise vibratory machines and it is a pretty darn powerful thing. I am wondering if it can be used to mill individual chemicals using a container and media in the same way you do with a ball mill? The idea being the media will bounce against each other rapidly crushing anything between it into very fine particles.

Just done a trial run with coarse salt using money as the media and I can say it works perfectly the powder is flour like within 2 minutes and so fine it floats. The good thing about rapid vibrations seems to be in how it seperates the large particles from the small allowing the media to grind them down. Leave it on for an hour and I am sure you will get powder that will pass 300 - 400 mesh.

Edited by pyrotechnist, 15 November 2008 - 05:00 PM.

[crystal palace fireworks]

Think you may have hit on something there!, do you have a picture of the excercise machine?

[pyrotechnist]

It makes coarse salt rock into flour within 10 minutes and coarse garden direct KNO3 into a powder finer than icing sugar. Here is a picture of one



You basically secure the milling jar on top of the vibrating plate and turn on full power for how long you want. The good thing about it is the coarse particles are thrown up at the top for grinding while the smaller particles are stored at the bottom making a fast and even milling. On close inspection the media rotates, flips and hits each other all at the same time crushing and trapping large particles instead of just turning against each other like within a ball mill.

Edited by pyrotechnist, 16 November 2008 - 06:41 PM.

[Mortartube]

I wonder if an inverted oritbal sander would do the same thing if it had a board strapped to the underside and a container attached to that (with bungees for instance).

Edited by Mortartube, 16 November 2008 - 06:54 PM.

[pyrotechnist]

That may also work to, isn't this similar to what an hammer mill does?

[Mortartube]

Mmm. I must give that a go tomorrow. I got a brand new one for about £2.50 in a company clearance. I will do some KNo3 and let you know how it goes.

[pyrotechnist]

Please report back on if it works or not. This seems like an alternate method for people with no time to build a mill and want fast and effective results.

[wjames]

you should look up black powder manufacture, optimizing and testing - by von maltitz.

He makes several references to vibrating ball mills, and how effective they are.

If i remember correctly, the general theory was that it was very very effective, for single ingredients, but isnt safe for mixed compositions.


i think a orbital sander would be too high a speed.

[Mortartube]

Even if it isn't safe for mixtures, it may allow people to make airfloat charcoal for instance. Whilst their mill is doing the really useful job of making a previous batch of optimum BP.

[wjames]

without a doubt.....It could be very efficent, although i would think the media will be critical to it working well.....As opposed to round edged media, like balls, i'd have thought sharp edged media, like cubes, or cuboids, or random shapes would work better.

Coins are a good idea, lots of surface area.

I wonder what kind of media erosion a vibrating mill would cause.......

Could be a very interesting topic....... ( looks throught the mrs "drawer" for a suitible device )

[pyrotechnist]

If the black powder comp is wet then I think it will be generally safe as long as you are using non-sparking media and container etc. I would assume a general ball mill will generate more friction compared to a vibratory mill due to the nature of the media movement and long duration whereas a vibratory mill seems to grind powder very effectively (this test was done just using coins) to powder within minutes compared to hours.

After using coins for a total of say 2 hours doing my test I do not appear to see any erosion but I ain't sure what will happen if they are used for days on end, weeks or even months etc. One thing if you use coins use coins that date back to 1970 etc as these use brass and copper whereas todays coins use copper plated steal.

Edited by pyrotechnist, 16 November 2008 - 08:13 PM.

[wjames]

thinking's no good....thats how accidents happen....I wouldnt put bp in the vibrating mill untill you have proven beyond doubt that its safe.

I don't agree that a ball mill(rotating) creates more friction

Friction between 2 surfaces - the balls "rolling" over each other against 2 surfaces, with powder inbetween them, vibrating.......i reckon that the vibrating mill will produce more friction....BUT thats a good thing, when milling single ingredients.


Just my opinion mate.....i'm very interested in the outcome of this one.

[pyrotechnist]

No problem, I do believe that if any BP is milled within a vibratory mill then the powder should be dampened. If anyone is interested I can get a video of how the media moves when the machine is going. The movement, this is on an exercise vibratory machine, seems to make the media turn around like a ball mill while simultaneously hammering the media together and making them move under and over each other. I know it isn't a very good explanation but it is the best I can explain it.

[wjames]

a video would be great......

I suppose, it'll all come down to the criticals......Speed of vibration( HZ ) vibration distance, Vibration acceleration (M/s), and lastly....Vibration axis...1 2 or 3.

[Arthur Brown]

http://www.mancheste...g_Machines.html and go down to the spirator vibro. Now if you could blow charcoal chips in and blow airfloat out But how much mess would that vibrating drum cause if the lid leaked a little dust.

Still wouldn't trust it with mixtures though

Edited by Arthur Brown, 16 November 2008 - 10:47 PM.