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Blaf

Ball-Mill

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Finally, there is an image of two plastic jars I use. The smaller one is 75mm while larger one is of 110mm inner diameter. Smaller one is open so that you can see rubber O-ring taken out...when it is set in place (inner rim of the tube) and end cap pushed tightly, whole thing looks like one on the right. I mounted a handle made of brass electrode 5mm thick threaded on both sides, bent at right angle and fastened to end cap. This makes handling much easier...especially opening. Note small screw on both end caps - these are ones for safety freaks I mentioned before. The other useful purpose of those screws is when you're closing this type of air tight jars, you should practically deflate it to do it.
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Blaf

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I was also thinking about making the jar similar, but I found a different way.

It is 24cm long and 10,5cm inner diameter.
One end cap is glued to the pipe.




But I have a question, how much of the jars volume should be filled with grinding media and how much free space must be left?

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Nice jar indeed. I like those orange end caps. Now, how much media can be stuffed inside and still efficiently grind your chems. I'm sure there should be someone making calculation taking into consideration volume of the jar, size of media and blah, blah, blah. I have a simple theory - you can fill your yar almost full but then, your media would not have sufficient space to bump and grind your stuff. Therefore, more than 2/3 of the overall jar volume should not be exceeded. At least I never did.

Blaf

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I have a theory, that 1/3 of the jar would be filled with media, 1/3 with chems, so when the chems fall in the empty spaces between the marbles, it leaves something, roughly 1/2 empty. There will be lots of free space where the marbles can grind the stuff....

My jar is ~1.8l voluminous.

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I just recently tried making my first batch of bp in a 3 pound ball mill. It has a rubber barrel and lead media. It is identical to the 3 pound mills sold at united nuclear. I must say I didn't make my own charcoal. I bought a bag of scott's charcoal. The ingrediants said 100% charcoal. So I figured It couldn't be that bad. After 15 hours of milling my media was covered in a thin coating of the powder and every ball was polished to a hematite jewelry look. There were two large sphere-like objects. I figured were just balls caked with bp. They were solid bp through. And there was very little powder at the bottom of the jar. The powder burned poorly and I was very disappointed at the whole thing. Any idea of why it balled up? And any other tips are much appreciated.

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If you simply tossed a few chunks of that charcoal into your milling drum, that's definitely wrong. Media could not mill it as you might expected...charcoal should have been crushed into much smaller particles and then put into millig drum.
If you'd crushed it into powder and those round objects emerged from nowhere, something is terribly wrong with powder. Moisture or some sort of parafine soaked in chunks could have caused clumping. No other explanations come to my mind.

Blaf

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With my BP I also experienced something similar, I also had some BP balls wich formed on their own but since I wetted my mix I think it was because of that.
So I let my jar to stand open for a night and milled again and then it became a powder mostly and the little lumps I had left contained a little piece of charcoal in the midle so my charcoal also wasn't fine enough before I threw it in :cry:

But lets hope we have better luck (charcoal) next time.

Pirate

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Well I had grinded my chem's in a coffee grinder first and when I crushed the balls with a spoon they were powder all the way through. Maybe it was just moisture, but I had tried a dry mix. Living in a california desert the climate is very weird. When summer hits the air will be much dryer, and hopefully I'll have figured out making charcoal by then.

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i made the main base and i attach the roller with pulley and the whells.
Also the motor attached under the pulley..that's all
It isn't difficult to make if you have the materials

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HI all! :P
I'm building my first ball mill, but I have some problems with the trasmission with pulley... :lol:
I have a washing machine motor 400 rpm with 3.3 cm DIAMET. pulley. This pulley is connected with another pulley 4.5 cm DIAMET. with 0.9cm propeller shaft . the jar is 13.3 DIAMETR and rotates on the 0.9 propeller shaft. I've calculated 99rpm on the jar theorically. Today I assembled the ball mill but the jar runs at 15 rpm :)!! Someone can help me?

p.s. to calculate pulley size and rpm I used this programm!
http://gadi.agric.za/software/renting/pulley.php

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