635 replies to this topic

[paul]

I?m experimentating with this type of motors right now, too. I got two of them 4 free. They are a bit too slow (about 80upm) but are quite powerfull. One motor can rotate a jar with 150 14 and 15mm stainless steel balls easily. I mounted the motor directly to the jar.

It works well and these motors are completely closed. So: No sparks etc. They are made for continuous action. But only if you cool them down. In cars the airstream cools it. For a ball mill two cheap 80mm fans do the job.

So i think, they?re really worth to experiment with. I supply them with an old AT power supply....

I used one to rotate my star rolling bowl, too. You can look at it here (Not finishes yet.)

Pic 1

Pic 2

Sorry for the quality of the pictures. (mobile phone cam....)

Edited by paul, 17 January 2005 - 09:25 PM.

[Flashy]

There is always the option of building a thermostat to turn off the motor when it reaches a preset temperature, if anyone is interested i can draw up a schematic. I'll be building one this weekend.

[PyroKid]

Hi Flashy,

The thermostat idea doesnt seem like to bad an idea at first glance, but it is important to remember that different chemicals will react at different temperatures, and also that heat can serve as a catalyst towards most reactions.

If the thermostat idea is to go ahead, it will involve gambling on what temperature could be deemed the adequate temperature to set the thermostat in order to cut power to the moter at a temperature which will be below the level which will be of any effect to the mixture.

[s2525]

Or maybe a heatsink like you would use in a computer to keep motor heat down?

[Phoenix]

The reason for cooling or resting a motor is to protect the motor itself, not to prevent it from overheating the contents of the jar. In any normal set up the motor temperature would not affect the jar, and usually quite a lot of heat is produced within the jar through friction - that is where all the energy put into grinding goes. The motor's temperature doesn't affect this.

Remember that motors DO get hot when they are used correctly. The fact that a motor is hot doesn't necessarily mean it's being overworked. Most motors will have some kind of fan built into them anyway. If the motor is really getting much too hot, then it probably isn't big enough to do the job.

[evilgecko]

My current ball mill is direct drive using a windscreen wiper motor. I've had it for abouyt half a year now using it basically 5 hours a day. It capactiy is small, 100g. The motor is cooled with a computer fan placed beside it. Before I had the fan it worked fine, but you could smell the smell fo melted plastic. Now you can't. But do remeber most motors are designed to be hot, and mine is almost to hot to touch (around 60C). The heat reduces the friction wear, actually prelonging the life of the motors.
I dont have any pics but I have a video of it running.
Ball Mill

By the way I have outgrown this ball mill and I'm currently deisging a new one which should be able to do 1-1.5kg of BP at a time.

[ProfHawking]

I have a small ball mill, the jar diameter is about 11cm. I am worried about the media inside just sliding round, not tumbling. It doesnt make as much noise as i thought it would. The inside of the barrel is smooth.
Should i add some vanes or some other things inside to make the lead balls jump and tumble more?
If so what is the best design? i dont want unmilled powder collecting in the edges of the vanes really

[Stuart]

I have used araldite to glue two wooden bars to the inside of the mill. It increases the efficiency to no end, you should do it

[Andrew]

My current ball mill is direct drive using a windscreen wiper motor. I've had it for abouyt half a year now using it basically 5 hours a day. It capactiy is small, 100g. The motor is cooled with a computer fan placed beside it. Before I had the fan it worked fine, but you could smell the smell fo melted plastic. Now you can't. But do remeber most motors are designed to be hot, and mine is almost to hot to touch (around 60C). The heat reduces the friction wear, actually prelonging the life of the motors.
I dont have any pics but I have a video of it running.
Ball Mill

By the way I have outgrown this ball mill and I'm currently deisging a new one which should be able to do 1-1.5kg of BP at a time.

The first mill I made was a direct drive design. I used a geared motor I pilfered form a photo copier. I rivited a plastic bottle cap to the end and used the removable plastic seals from coke bottles to provide an air tight seal. It's capacity was 300grams of bp. Since I upgraded it to use 3 litre cider bottles it's capicity is 400-500 grams. It was quite a neat and compact, although bodged design.

[Flashy]

Hi all,

I was speaking to a wise fellow at work today, I didn't realise i had a wealth of knowledge on the subject of pyro working so close to me. Anyway to the point of this post, I mentioned the subject of milling media to him. He said that most brass bar contains phosphorus, apparently its added as part of the standard procedure for manufacturing brass. I have looked at some brass suppliers and some sell low phosphorus content brass.

Just wondering if anyone knows of any study or research carried out with regards to compatability issues, or of course if it is even significant enough to consider.

Dave

[Richard H]

Never had a problem myself. Brass has been used in commerce for a long time.

[Andrew]

Hi all,
most brass bar contains phosphorus, apparently its added as part of the standard procedure for manufacturing brass. I have looked at some brass suppliers and some sell low phosphorus content brass.

phosphor bronze is a very common type of brass. I think the alloy is harder than standard brass, which is relitively soft by most standards.

Edited by Andrew, 03 March 2005 - 11:09 AM.

[ProfHawking]

I have been working on a new ball mill/star roller for a while, as i decided i wanted a star roller and my s**tty old ball mill wasnt doing great.
Its finished now, and i think should work nicely! what do u guys recon:
Pics:
http://highspeed1.cl...ewmill/mill.JPG
http://highspeed1.cl...ewmill/belt.JPG
http://highspeed1.cl...ill/springs.JPG
http://highspeed1.cl...mill/nascar.JPG
http://highspeed1.cl...ll/bearings.JPG
Vids:
http://highspeed1.cl...wmill/stars.avi
http://highspeed1.cl...ewmill/mill.avi

If any of you want to know where i got parts etc, pm me and ill try and help

[thecult]

hi, im planning to buy myself a ball mill. I have found this site,

http://www.delscope..../lapidary01.htm

i was looking at the Tumble Master, 3lb (1.3kg). Its the cheapest priced one i have found and looks quite good.

Any comments on it? (want to know if people think its up to the task of making good BP, dont want me wasting my money now, do we?)

Thanks

[broadsword]

ProfHawking That looks very good!
But as im a keen fisherman I couldnt help notice the fishing 'silk' or line in the background, are you a fisherman or was it just used in the mill?

Edited by broadsword, 08 March 2005 - 10:42 PM.