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Recommended small ball mill for BP?


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#1 DrJones

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Posted 15 March 2021 - 04:07 PM

I'm familiar with best practices for mixing and milling BP. I note several very good ball mills are sold, yet every one is over $100. Two questions here:

Any particular brand name of ball mills available for $100, or less, or a bit more? I'm not into building a mill from scratch, so prefer one suitable to plug in and go.

Many smaller rock-tumbler "mills" have a round milling case, while other larger ones are usually multi-sided. I sense the multi-sided mill barrels are much better for BP milling, but has anyone had success with smaller, round-barrel mills?

I can easily run the mill for longer periods of time, if needed. Time isn't of the essence for me, though approaching Goex burn rates is what's wanted and needed, Skylighter promotes red-gum BP (unmilled) as being quite "hot," and I've had good results with that mode. Still, a ball mill will likely make "better" BP than any red-gum blend--I suspect.

Comments and ideas welcome. Thanks.

 

Edward in New Mexico

 



#2 mabuse00

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Posted 15 March 2021 - 05:06 PM

Dont go too small.

 

The milling process depends mostly on balls hitting each other, smashing the charge.

To get a good hitting power you'll either very heavy balls or a great falling height -> large drum diameter.

 

My barrels are some 12cm and I dont think you can go much smaller if you want a reasonably effective mill.

 

 

but has anyone had success with smaller, round-barrel mills?

Yes.

The right speed is important. if you get near the critical speed the balls start to get lifted up on the walls and come crashing down again.

 

 

I can easily run the mill for longer periods of time, if needed. Time isn't of the essence for me

Nevertheless you should try tro run your mill as effective as possible, let alone for wear of mill and media. Often the right setup makes the difference between the milling having very little effect to making very good BP in only 2 hours.

24h runs some people often mention is BS in my opinion, if it takes that long your doing something wrong.

 

 

Skylighter promotes red-gum BP (unmilled) as being quite "hot," and I've had good results with that mode.

That might work for you if the charcoal as it is delivered to you has allready gone through a ball milling or similar process and is of good quality/suitable for BP...



#3 Arthur

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Posted 15 March 2021 - 05:29 PM

Put 100 pyros in a room and you will get 200 different answers to your question.

 

For my 2p's worth, if you use a small hobby rock tumbler with ceramic media will give OK powder, the time you need will be determined partly by the preparation of the ingredients.

Lortone certainly do a 12 pound rock tumbler which is big and needs much media and ingredients. Typically a rock tumbler will not turn a full load of lead media and ingredients the motor and belt are not strong enough. I really like ceramic media.



#4 SharkWhisperer

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Posted 16 March 2021 - 04:51 PM

Skylighter's BP kits are complete crap, especially the "red gum"  kit. Red gum has no role in pyro BP. The charcoal used in both (airfloat hardwood) is about the worst charcoal that you can use for making decent BP--you'd get equivalent (or better) performance from crushing up some lump bbq charcoal (not briquettes). And better results again making your own charcoal (even in a gallon paint can to learn). And if you compare Skylighter prices to essentially any other pyro chem source (fireworkscookbook, pyrochemsource to name a few), you'll see that you're often paying double the price for the exact same items. They are grossly overpriced. If you unfortunately bought one of the BP kits, you can use all of the ingredients, just not for decent BP. The charcoal is just fine for slow-burning star formulations. Crap for BP. Nitrate is fine. Sulfur is  fine. Gum is fine (for fuel/binder in stars--not in BP). Just overpriced. Compare the total cost of a Skylighter "kit", either, to the same poundage of chems in that kit at FWC, and you'll see the Skylighter kit "savings" costs double what individual components usually cost.

 

It is not at all difficult to make BP that is much faster than Goex.

 

If you have the time, an 8 hour spin in an HF mill, with quality chems, will give you some very potent powder after wetting & granulation. It's not the most efficient mill for sure, but quite sufficient to get the job done for hobbyist-sized batches milling over a longer time frame than a more expensive unit that you might not be ready to commit to purchasing at this point.



#5 justvisiting

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Posted 16 March 2021 - 06:25 PM

thumlers-tumbler-barrel-9lb.jpg

This is the shape of mill jar that is most efficient. In my limited experience, mill jar diameter is more important than RPMs. A 4" diameter mill jar takes a long time, as others have pointed out. A 6 or 8" diameter jar of the same volume would do the job much faster and more completely.



#6 Piccaso

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Posted 27 March 2021 - 08:23 AM

The cheapest way to get into milling is to build your own. However mills and milling media are far from cheap.

This is the best mill jar I have found............

https://www.woodysro...ill_Jar_.html#/

I use this mill I made the mods myself but if I where to do it again I would just buy one already done as I didn't save much.

https://www.woodysro...lb_Mill_.html#/

This is a great deal on media on this site as well.

https://www.woodysro..._Milling.html#/

 I would recommend saving your pennies and just buying one from here complete and ready to run with the mods done already, it will be your best friend in pyro and you will save yourself time and money screwing around with the small crappy mills as you will just end up here sooner or later if you are serious about this hobby.


Edited by Piccaso, 27 March 2021 - 08:24 AM.


#7 hanabi

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Posted 27 March 2021 - 07:16 PM

Here are some. I'm going to get a couple drums.

 

https://covington-en...g.com/tumblers/

 

https://www.therocks...ler5.html#Large

 

http://www.diamondpa...m/products.html

http://www.diamondpa...020 catalog.pdf



#8 Arthur

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Posted 28 March 2021 - 03:50 AM

Have a look here https://www.therockshed.com/tumbler4.html Lots of tumblers from 3 pounds to 24 pounds (rock rating) I strongly prefer round rubber drums as they run extremely quietly. Most rock tumblers will not turn a full drum of lead balls but ceramic balls work fine. My mill holds about five pounds (rock rating) so it gets 2 kilos of balls and a kilo of mix. I leave it for 12 hours because that suits my work shifts but it runs so quietly that no-one notices the sound.



#9 Mitchell

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Posted 24 April 2021 - 01:43 PM

Hey there. Building a small milk myself. I wanted to ask. Why does everyone use belt driven instead of chain and sprocket? I don't see any more risk other than if something jams it's going to be much worse with chain rather than a belt slipping.

Am i missing something?

#10 Arthur

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Posted 24 April 2021 - 02:35 PM

Most people run cheap, belt and two rough pulleys are cheaper than two sprockets and some precision hardened chain. Plus for safety belts slip or flip off but chains must destroy something if the system fails.



#11 Mitchell

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Posted 24 April 2021 - 02:55 PM

That's what i figured. I was just asking because i have chain on hand as well as sprockets but just wanted to know if i was missing something. Thanks for the quick reply!

#12 BetICouldMake1

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Posted 25 April 2021 - 05:48 PM

I'll add that your ball mill will inevitably get dirty with mill dust and the nitrate will rust up any bare metal. To a lesser extent the metal rubbing on metal could be a spark hazard. I realize your running an electric motor, but still.



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