Ball mill

[aquaman]

Tried my new ball mill today. Wipped up about 100g of BP. This mills efficiency is way better than the efficiency than that of my homemade mill (which I'll admit was crappy). It probably powders things about 2x as fast as my old one. After about 4 hours of milling I added hot water to make the BP a little faster. Should be dry by tomarrow.

[PyroJoe]

I bought the Harbor Frieght 3lb tumbler last year and it lasted quite a while, I could make 200 grams of really fast bp in about 8 hours. Although I had a belt break and now the rubber seal is falling apart on the lid, so it leaks powder everywhere now. I didn't ever wash it though, so that could have been part of the problem.

 

I am now considering a 15 lb. Thumblers tumbler. I think I can get it for about $120... It has a steel hexagonal drum with a rubber insert, so you can take it out and wash it easily. I was wondering if anybody here has used a thumblers tumbler. Im willing to pay 120 if its going to last. I just need a lot more capacity, so I can make large batches of BP.

[aquaman]

Wow 15lb ball mill. That's alot of BP (3-4 lbs.?)

 

The cheapest 15lb. ball mill, I could find was on FireFox's website for $172 dollars.

 

The only problem with a steel drum is if the BP ignites there's going to be a small shrapnal problem . So you'll need to have that ball mill far away from anything/anyone important, and have a kill switch from far away.

[justanotherpyro]

If you're willing to put forth the effort, look for a tread mill and modify it. Great duribility, and you can make good drums rumaging around construction sites for pipe. Visit a plumbing supply for the end caps.

 

The drums are definately the difficult part to work with, and getting a fully functional mill w/o any hassle would be nice.

[aquaman]

Justanotherpyro has a point if you can get a tred mill $50 and a couple of 5 gallon water jugs($20) you'll be able to make more BP than that 15lb. ball mill. That 70 dollars is an over exaguration by the way and you could probably find both things cheaper somewhere if you look.

[PyroJoe]

Yeah ive been trying to decide whether to build one myself or just buy that one. Usually i like to build things myself. The hardest part of a home made ball mill in my opinion is the drum! I just like the idea of having a good quality steel drum with easy access and a good seal. It's difficult to find end caps for anything above 6" pvc.

[Mephistos Minion]

Im getting one of those red barrels (it hurts my wallet at $150 AUD though) I am using it on my home made mill rollers as they are good quality steel with industrial bearings. I might change the motor for one with a cooling system.

[justanotherpyro]

5 gallon buckets is a stretch for an amateur pyro. So far my list of drums includes : the pump and spray weed killer bottles, plastic coffe cans, sewer and or ABS pipe with fittings from a plumbing supply, protein powder jars, smaller plastic paint cans and a few others. Basically my dad and I have been at work trying to get a decent jar together for a few weeks now.

[nesler]

If you poke around on ebay, you can find small rock tumblers (good ones of solid steel) for less than 30 bucks. If you really hunt around and bide your time, you can do really well and nail down a large one for under 40 bucks. Lortone is a good brand. I've seen working Lortones come up for bid that were at least 25 years old, looked like they'd been to hell and back, and still worked.

 

For media, I found that large size lead round ball shot (0.535" in diameter) worked pretty well. Not totally ideal, according to Sponenburgh's equations, but still pretty nice. You can probably find them in your local gunshop. The ones I used are made by a company called Speer. You can also get them online. BTW, does anybody happen to own a copy of his book?

 

Mumbles, Mummmmmmmbles....

[Frozentech]

If you poke around on ebay, you can find small rock tumblers (good ones of solid steel) for less than 30 bucks. If you really hunt around and bide your time, you can do really well and nail down a large one for under 40 bucks. Lortone is a good brand. I've seen working Lortones come up for bid that were at least 25 years old, looked like they'd been to hell and back, and still worked.

 

For media, I found that large size lead round ball shot (0.535" in diameter) worked pretty well. Not totally ideal, according to Sponenburgh's equations, but still pretty nice. You can probably find them in your local gunshop. The ones I used are made by a company called Speer. You can also get them online. BTW, does anybody happen to own a copy of his book?

 

Mumbles, Mummmmmmmbles....

Yeah, I've got his book. Used his design almost as-is for making my ball mill, and it works great. The theory of ball-milling part was an interesting read, but what I liked most was the actual plans to follow, with a nice materials list to cut down on shopping trips to scrounge parts.

[ULTRABUF]

Hey justanotherpyro, how do protein powder jars work for milling? Because I have a crapload of them in 3 different sizes.

[Mumbles]

Sorry Nesler, it is one of the books on my list. I personally don't really like his jar design. I would think there would be powder trapped in the gap between the pipe and the endcap/reducing adapter. I am going to be making some soon. I think I will make some wooden circles for use as endcaps being held on with rubber vacuum cleaner belts. I don't like passfire's use of screws. That seems like it would make any explosion more powerful, and cause unnecesary steps for opening and closing the container. I would suspect that the inner disk of wood would become filled with holes over time as holes are enlarge and the screws no longer bite.

[BPinthemorning]

I have a three lb rock tumbler from harbor fright, and for some reason, the drive attached to the motor with the fan on it has worn down the outside and the belts wont stay on... If anyone knows why this happened or has had a similar problem, I would appreciate your feedback. It looks like you can't replace the part, so I will most likely go through a difficult argument with Harbor Freight in order to get a replacement...

[Swede]

I would think there would be powder trapped in the gap between the pipe and the endcap/reducing adapter. I am going to be making some soon. I think I will make some wooden circles for use as endcaps being held on with rubber vacuum cleaner belts.

 

I agree 1000% and I like your idea for disk end plugs. I'm looking into turning HDPE tubing right now into good jar stock, and the end caps are the trick. I think I've come up with an answer, but the O-ring sealed end cap is yet another option.

 

Having nooks, gaps, and crannies in a jar is really problematic, as they really do seem to accumulate chems that stick and thus avoid good grinding action. Who wants to screen their product every time? I expect a good ball-mill jar to produce consistently and without fuss. For this reason, I like the lortone jars best, but they are expensive.

[Sylar]

I've made a mill jar using a piece of 200 mm diameter 3 mm thick stainless steel pipe.

End caps were made from 5 mm thick iron sheet, two circles cut to fit inside the pipe, two circles cut to the same outside diameter as the pipe.

Bolt or weld the small circle to the large circle and make a hole in the centre through the whole thing.

 

For assembly I used a stainless steel M8 threaded rod 20 mm longer then the pipe, threaded in one of the end caps and locked in place with a nut. Then the pipe is placed on this endcap, followed by the other endcap and a butterfly nut that can be fastened by hand. O-rings can be used to make a good seal if your metal working skills can't make that seal. This jar was specifically made to mill metal powders which would otherwise destroy my proteïn powder milling jars. Soft iron cut bar stock is used for media.

 

The things I don't like about it:

Noisier then plastic jars

No weak points yet to let overpressure out, although the threaded rod will be the first thing to go, directing explosive force along the length of the pipe.

Untill the endcaps are made from SS aswell, no oxidisers can be milled in it.

The threaded rod pulling both end discs together is exposed to the milling action and chemicals.

 

The things I like about it:

Can last a lifetime

Airtight closed when using o-rings

Wearing parts (like the threaded rod) can be changed when required

Heat, chemical and wear resistant

End caps can be used for different pieces of the same diameter pipe

Easily cleaned since you can take everything apart.

 

Pics can be added, but I don't have a whole lot of time right now, so someone remind me to do so on tuesday :-)

 

EDIT:

Forgot to mention, this jar design can also be applied to less durable materials.

A thickwalled PVC/ABS pipe and plastic, wood, whatever end plugs can do the job just fine for most things since the end plugs suffer the least from the milling action.

Edited August 15, 2008 by Sylar