Show and Tell - Ball mills.

[Updup]

Yes, lift bars make a darn big difference

Mark

 

Sounds right…

 

 

What RPM is your mill running at?

 

And how long does your lift take?

 

What's the diameter of your drums?

 

How many lift bars do you use?

 

How are you preventing material from getting stuck or packed around the lift bar?

 

And last but not least, what material is your lift bar made of and how is it fastened to your drum?

 

 

I'm running about 60-75 RPM, and I get great powder at 3 hours, but will sometimes go to 4 if I have the time, 2 is pushing it for me.

 

I imagine a larger drum would be a better candidate for lift bars, since it would be more difficult to run it at good speed, and much easier for the contents to slide at the bottom of the drum. My drum is 4".

 

One lift bar would be enough no? 2 or more just seems overkill.

Edited March 17, 2011 by Updup

[Mumbles]

All motors heat up somewhat. However, it sounds like you should probably get a better suited motor. If they're not designed to run for long periods of time, they will likely fail faster. The next time I get one made I am without a doubt going TEFC.

[marks265]

 

 

Sounds right… I am glad it sounds right to you

 

 

 

What RPM is your mill running at? Varies depending on if I use lump charcoal or air float and change through the run. Yes, I have variable speed.

 

And how long does your lift take? Just to mill it----1/2 to one hour depending on if I have lump or air float charcoal. Then dampen and push through screen (rice) to get about 2FA.

 

What's the diameter of your drums? 6"

 

How many lift bars do you use? 2 each, 180 degrees apart.

 

How are you preventing material from getting stuck or packed around the lift bar?

 

I use dry chems and never a problem. I bet your charcoal has moisture. Put some in clear plastic bag, seal put in sun. You will know. If not try your other chems but charcoal is usually the culprit whether you think it is dry or not. This is what I found in the past when I do not have my own on hand.

 

And last but not least, what material is your lift bar made of and how is it fastened to your drum?

 

Sacrificed a piece of PVC pipe off the pipe I bought for jars. Cut a length as long as your pipe that you made the jar with. Cut that piece the long way into 3/8"-1/2" wide strips---watch your fingers. Glue in with the same PVC Glue you used to assemble jar, assuming you used the correct glue and primer. Been running for years.

 

 

 

I'm running about 60-75 RPM, and I get great powder at 3 hours, but will sometimes go to 4 if I have the time, 2 is pushing it for me.

 

Sorry to hear you have to spend so much time and energy. It will get better I hope.

 

I imagine a larger drum would be a better candidate for lift bars, since it would be more difficult to run it at good speed, and much easier for the contents to slide at the bottom of the drum. My drum is 4".

Yep, 6" or larger would be better.

One lift bar would be enough no? 2 or more just seems overkill.

I have 2 it works for me. You could try 3 or 4 depending on mill jar speed.

 

Good luck

Mark

 

[MadMax]

From what I have learned in my series of home made ball mills rolling is bad. You want the media to do a little bouncing around to sort of smash the particles down to a very fine size. What I am wondering is if attaching some sort of a vibrator to the container would cause a rise in efficiency. I've seen the tumblers used to polish or deburr metal parts and that's where I got the idea.

[Mumbles]

Those vibratory tumblers are actually extremely inefficient for what we do.

 

If your media is just sliding around, you should fix that. Ideally you want a cascade of media. Think something like what a star roller looks like or a constant avalanche of media. It crushes particles just fine and will probably jump around some on it's own. If you attach some sort of vibrating device to your mill I'd be worried all the particles would start settling out from in between the media. I'd imagine most motors and media sloshing around induce enough vibration as it is.

[Guest no6]

Got the idler axle and the drive axle assembled on the mill today and mocked it up with the motor and pulleys to test the turn speed. The drum is an empty 210 pound bright flake aluminum drum, about 40 gallons with 750 golf balls in it. The mill operated very well, but the rpm is still off. It was turning at 95 rpm and I'd like about a third of that. Going to have to add a gear reduction axle with a couple of pulleys on it to reduce it another 3:1. I was worried whether it would have the power to turn a drum that is going to weigh between 70-150 pounds but it turned 70 with little trouble. I think I might switch from belt drive to chain drive though because the weight was really working the belt over. I'm thinking at the slower rpm it might be okay, we'll see. Anyhow, this is still in rough construction phase, I will paint it and make it pretty when it's done.

After final axle installation

Mock up

 

There seems to be no half measures with you. It's either GO BIG or GO HOME.

 

Awesome. Thanks for sharing!

[dagabu]

We bow to you O CPLMAC!!!

[Guest no6]

All motors heat up somewhat. However, it sounds like you should probably get a better suited motor. If they're not designed to run for long periods of time, they will likely fail faster. The next time I get one made I am without a doubt going TEFC.

 

Link?

[Mumbles]

To what exactly?

[pyrochris732]

if anyone is looking for a replacement jar for their mill, definately check out Lortone jars. Mine came in the mail today and its built really friggin solid. Its a 6 lb. I was expecting similar design to the 3 lb harbor freight ones but this is thicker rubber, and the metal cap seems much stronger.

 

I paid 40 bucks for it.

Edited March 18, 2011 by pyrochris732

[cplmac]

To what exactly?

I'm thinking TEFC. I'd actually like to see that too because I'm not sold the motor I'm using is going to go the distance.

[Guest no6]

Yeah, I was referring to the motor.

 

But how about the lifter bars? Are they necessary with the mill you are using (ie: the one I ordered)?

[pyrogeorge]

I make a ball mill,you can see my pics at the gallery.

Also,the key is what charcoal did you use..a lof of people use bbq charcoal,but you can't make so fast BP.

I use pine or white aspen charcoal(homemade).White poplar is faster than pine.

Another point is to not overmill your jar..i use less than 1/2 of media and 1/4 of composition,because this values are theoretical..

Of course you must pay attention at rpm you need the jar for optimal milling,but i made my mill to rotate 20rpm more of the optimal speed.

But i made o lot of tests before i have the final result..

i will post a video soon,to see how it burns..it lift 6' shell without problem

Here is the video.Details you can see in the media page.

 

http://www.amateurpyro.com/forums/gallery/image/751-bpwmv/

 

or youtube link

Edited March 19, 2011 by pyrogeorge

[Mumbles]

Would you just like a link to a motor? I'm sure there are better places, but I've always found them on ebay. TEFC isn't explosion proof, but it's a lot more resistant than a standard motor with exposed coils and the like. They make me feel safer if nothing else, and will hopefully solve some heating issues. They're not as cheap as standard motors, but really wont break the bank. If you keep an eye out on ebay, you can find a suitable one for $50 or 60. If you get one of the new, but surplus ones, they'll probably run you between $100 and 150. If you want to build a mill that rivals cplmac's the more powerful motors really aren't much more expensive, maybe $200 for a 1HP+ motor. Keep an eye on the motor specifications. I know very little about electronics, so I'd only be getting 1 phase, 50/60Hz, 115V motors. I know others can be made to work, but that is a bit over my head and beyond what I personally want to do.

[pyrochris732]

speaking of TEFC, i happened to see one today on ebay for 55 bucks, someone grab it!

[Guest no6]

Would you just like a link to a motor? I'm sure there are better places, but I've always found them on ebay. TEFC isn't explosion proof, but it's a lot more resistant than a standard motor with exposed coils and the like. They make me feel safer if nothing else, and will hopefully solve some heating issues. They're not as cheap as standard motors, but really wont break the bank. If you keep an eye out on ebay, you can find a suitable one for $50 or 60. If you get one of the new, but surplus ones, they'll probably run you between $100 and 150. If you want to build a mill that rivals cplmac's the more powerful motors really aren't much more expensive, maybe $200 for a 1HP+ motor. Keep an eye on the motor specifications. I know very little about electronics, so I'd only be getting 1 phase, 50/60Hz, 115V motors. I know others can be made to work, but that is a bit over my head and beyond what I personally want to do.

 

Um, no. That guy is crazy,

 

But seriously, the tumbler came in the mail today and I am quite pleased and ready to engage.

[cplmac]

Update, got some time in on the mill fabrication over the past couple of days. Good news is I'll be done with the fabrication tomorrow, bad news is there is a LOT of grinding to do on the welds before I can sandblast it and paint it. It works good so far, but I have no idea how the motor and gearbox will hold up. I think the motor will be okay, the gearbox is just an unknown. I reworked the design and opted to not use belts or chains. I'm going to use a motor shaft driven directly into a 20:1 reduction worm gear box. It turns the mill at what appears to be the perfect speed. I'm not sure how the speed will be with the big drum but with the smaller 35 gallon drum it turns perfect.

 

Pic 1

Pic 2

Pic 3

Pic 4

Vid 1

 

One thing is for sure, this thing is an absolute tank. Without the drum it weighs in around 30 pounds, I still have to fabricate and install the centering wheels tomorrow but that should go pretty quick. I'm not happy with the way it looks, but it's functional, simple and sturdy as hell.

Edited March 23, 2011 by cplmac

[Guest no6]

Will golf balls really work as milling media? I'm loving this.

[cplmac]

They work great, I milled 25 pounds of salicylate with them a month ago. Ran for about 4 hours and it flows like chinese perch, the .5% cabosil makes a world of difference when milling single chems.

[dagabu]

Mac, ever seen any negative consequences with using cabosil in your comps?

[cplmac]

Mac, ever seen any negative consequences with using cabosil in your comps?

No, and I would be surprised if I did. I keep it at a half percent or lower, so if you think about it theoretically the formulas are still %99.5 pure. Plus, cabosil is pretty inert, basically it's made from silicon or quartz. Apparently it's used primarily as a thickener in products ranging from milkshakes to toothpaste, odd...

[cplmac]

I finished the last of the fabrication today after work, got all motivated and went ahead and broke it down, cleaned it up and painted it as well. I made the barrel centering wheels adjustable because we plan on using two different sizes of barrels. Tomorrow I will reassemble it and it will be ready to roll...

fabrication complete

broken down for cleaning

hung for painting

painted frame

Hopefully the paint job is satisfactory, three coats should be enough but the coverage was not what I was hoping it would be.

[cplmac]

All done, now I just have to fabricate a lid for the HDPE drum.

 

Painted ready for reassembly

Painted and reassembled

Adjustable centering wheel extended (look on right side)

video of the mill running

[jermain]

Hi guys,

 

Made my first ever BP today and tbh i thought it was quite a success. Made a few bangs and rockets all mixed by hand with pestle and mortar. Needless to say i now have a sore arm, can anyone point me in the direction of were to buy a decent Ball Mill from (preferably not on the internet but rather a DIY shop etc.) and what is the best to buy/not buy.

 

This is my first time on this forum so not really sure where the general location of most people is but I am from the UK near london so if anyone knows anywhere I could grab a ball mill from would be immensely helpful.

 

Thanks

[cplmac]

Tumblers Tumbler Model B

This is a really solid ball mill and a huge chunk of the hobby pyro community either has one or has used one. We have two in our shop and it's a good little mill. Very common as well so you should be able to find one in the UK, just check around local hobby stores and ask for a rock tumbler.