How many hours do you ballmill your BP?

[Ubehage]

Ballmilling is always a personal preference, I have come to understand that.

Depending on who and where you ask, the "optimal" ballmilling varies from 4 hours to a full day.

 

I would like to gather some experience from you:

How many hours do you ballmill your BP, and for what purpose?

 

And, propably the most important question: Can you mill for too long, and ruin the result?

[insutama]

I personally find with my ball mill 4 hours is perfect you want to mill Untill your black powder is all clumped together in a ball at that point you can't get it any finer

[Arthur]

My finding is that one should mill until the powder is as fast as possible, speed gain with mill time falls off with time. Your choice of end point should be determined by tests, for a larger diameter drum it's usually less than for a smaller one. Sometimes the time is just "for convenience but long enough" Mill while you are out, mill while the neighbours are out! I think it may be possible to overmill but only slowly and after a long time.

[nater]

I run the mill for 2 hours when making BP. If I am just mixing a star comp, I run it for 30 minutes so everything is well mixed but not as fine as possible. I see no significant gains past 2 hours with either one of my mills.

[insutama]

I still haven't made the upgrade on my ball mill to get faster rotations so I figure that's why mine takes 4 hrs to get that clump consistency

[Arthur]

My experience and understanding is that DRY powder doesn't clump ever, but powder with moisture does. -Til clumped, is a poor end point.

 

One batch I made was chems from the bag,- It clumped big time, another batch from the same bags but dried separately at 100c it's still free flowing dust after 10 hours (home from work!)

 

If ingredients are damp (wet!) then even the mix ratio will be wrong.

[DaMounty]

What I did were time tests.

 

1st test @ 2Hrs milling - 3g on diagonal sheet of paper

then every hour afterwards until I noticed no difference in burn times.

 

DaM

[insutama]

I'm not talking about wet clumped I just mean when you poor your media out of the mill container the bp is all compressed together like mine usually is a compressed ball maybe I'm wrong but I read somewere that when your blackpowder goes like this that's is what your looking for and it's done please correct me if I'm wrong

[insutama]

Da mounty what kind of mill are you using and let us know your results I'm curious myself

[Nickmaslo]

This is my first post (Woohoo!)

 

I have been studying this forum along with many others for quite a while. I picked up a lot of peoples replies, behavior and etiquette on the forum because I really don't want to be "that new guy" and get scalded for a mis-step. I just ordered my first ball mill. It is the Dual Drum Rotary Rock Stone Metal Glass Tumbler Polisher - 6 lb Total. The media - 100 balls of Lead .50 Cal, 495 diameter Roundball Muzzeloader Speer Shot. I am still setting up my work space, containers, getting ready for my first project, reading my books and formulas, terms and forums.

 

I want to soak up as much information as I can about ball milling and what are its limits, durations, capacity, beginner milling advice, media advice, etc.

 

Anything and everything really helps, I look forward to as much advice toward what's mentioned above and thank you for the chance to join a community that I have wanted to be apart of since I was a kid.

 

 

Edit ---- 6:30 EST 6/30/15

Edited June 30, 2015 by Nickmaslo

[Garydee]

100 balls of Steel .50 Cal, 495 diameter Roundball Muzzeloader Speer Shot.

 

Did you mean lead balls? as you won't be able to mill BP with steel balls.

[carbonhalo]

My mill is quite small.. it only does 400g batches, and it spins quite slowly so it is not a loud tumble action.

It is also solar powered and doesn't turn at all on overcast days.

Hence, I leave a batch in it for several days in summer... a few weeks in winter.

It gets turned end over end and tapped daily to redistribute clumps.

 

Nick... do you know if those steel .50 cal balls are sparkproof?

[Nickmaslo]

Speer Muzzleloading Bullets are swaged from pure lead and are exceptionally uniform without air pockets or voids. The smooth round surface provides better rotation and consistent accuracy.

 

Taken from midway USA website.

--------------------EDIT ---------------------------

http://www.midwayusa.com/product/2149111743/speer-muzzleloading-bullets-round-ball?cm_vc=subv2149111743

Edited June 30, 2015 by Nickmaslo

[insutama]

I think 200 balls is ideal in that mill that's roughly 5 pounds that's the same mill I have and I use 200 50 cal lead shots it works great I never bothered to speed mine up but alot of people that use this ball mill speed it up a little.

[DaMounty]

I have a home made unit. For the tumbler I used 5" of 4" dia Pvc with reducer to 3". For milling media I have 200 .50 cal lead shot. My belt right now is a waxed skate lace . 3 hrs is my mill time. There is a video of my burn test in this section. It's under BP - Hardness

 

DaM

Edited June 30, 2015 by DaMounty

[Nickmaslo]

I think 200 balls is ideal in that mill that's roughly 5 pounds that's the same mill I have and I use 200 50 cal lead shots it works great I never bothered to speed mine up but alot of people that use this ball mill speed it up a little.

People speed it up a little how, swapping the motor?

[Shunt]

There is an article on Skylighter's website that gives the details for increasing speed on the Harbor Freight mill, if that is what you have. I did it to mine and it helped decrease my milling time. Basicly you just disassemble the rollers and slide a length of hose in the drive roller to increase the diameter. I used heater hose and it works fine, I have run the crap out of that little thing and it just won't die. Good starter mill in my opinion as it has (2) drums, I use one for BP based comps only, and reserve the other with different grinding media for other compatable chems/comps.

 

Arthur also made a good point about the moisture content of the chems being milled. When I make BP the charcoal usually goes straight from the retort to the mill after just enough time to cool down and blade mill. I have never predried the KN03, however that might be something I would do if I had trouble with "clumping". 3 to 4 hours mill time works for me in this particular mill and anything over that the BP will "clump" in the back of the drum, however the end result is good enough for me after the powder is granulated.

Edited July 1, 2015 by Shunt

[Nickmaslo]

Genius, I just read that article, how amazing! I was overcomplicating my blueprints on my star roller (I was going to build one). Instead of a Gear Box Reducer I can just increase the diameter of the drive roller.

 

Anyway toward the topic of the thread, with the 80-90RPM "boost" to to the mill, I suppose the articles and information I have for BP can be reduced by about 35%. I have heard , 8 hours, 12 hours, 6 hours, a full day even. After a certain length of time, wouldn't any further milling be useless and one would have achieved the finest powder possible? (Assuming you frequently break up lumps and scrape down the sides of the mill)

Edited July 1, 2015 by Nickmaslo

[calebkessinger]

I have never had a , " little mill" but once you get a mill dialed in with the correct media and charge with (dry) chems it doesn't take long to mill powder to it's peak power. some have tested powder every 1/2 hour and found that a correct mill will get it done in 2 hours. That's about what I let mine go. give or take a few. moisture in the chems will cause clumping.. some people call that done.. It seems that works for me also. but again. I have never fooled with those little mills.

[insutama]

I have all my chemicals stored sealed with calcium chloride packages to keep moisture out and I live in a very dry area so I didn think moisture would have gotten into my chemicals so when my black powder clumps like this should i be Breakin it up and milling longer ?

Does modifying the mill to rotate faster put more strain on the Moter ? I would love to mod my mill but I don't have the right tools to get the clips off and I don't wanna end up not being able to get it back together so i figured it worked good enough the way it came but i it would save me a hour of milling I may try do the mod.

[Peret]

My mill is a Harbor Freight dual drum, I have several of them. I have enough zirconia media for five drums so that's what I use all the time, as I found lead is too soft. The zirc will mill a batch in one hour but I usually give it two. Lead used to take four to eight hours for the same performance and every time I ran the mill the balls came out a bit smaller.

 

I have 3 pounds of media in each drum - takes up half the volume, same as 5 pounds of lead - and mill 200g (8 ounces) batches. The mill can easily turn two 3 pound drums but can only manage one with 5lb lead media.

 

I have maintenance problems, the main one being the belts. I replace the floppy rubber belt with a polyester reinforced cogged V belt, Dayton 13V773, which is actually available at Walmart believe it or not - http://www.walmart.com/ip/DAYTON-13V773-FHP-V-Belt-Type-2L-1-Rib-13/40785500. It never slips, it never breaks, and once this is done you never have to worry about belts again.

 

Another annoying maintenance problem is the shafts and bearings. One of my mills seized up recently, and when I dismantled it to look at the bearings I found that the shafts are chrome plated, and the plating was flaking at one end. Bits of plating were embedded in the plastic bearing and seizing the shaft. I reamed out the bearing and rubbed down the shaft but it's going to happen again. When it does maybe I'll replace the shaft with steel drill rod and bronze bearings. I actually have the bearings, but I haven't replaced them because they need the end plate holes enlarged. These holes currently are keyholed and I can't drill them out and keep them concentric. On the other hand the cost of a new mill is less than I bill for one hour of my time, so I'll probably just buy a new one.

[Nessalco]

My mill is homemade, with 4" x 8" PVC jars half full of 1/2" and 3/4" brass rod cut into billets. I mill charcoal for 1 hour first, then add the remainder of the chems and mill for 3 hours. I don't seem to get any improvement after that.

 

Kevin

[Nickmaslo]

My mill is a Harbor Freight dual drum, I have several of them. I have enough zirconia media for five drums so that's what I use all the time, as I found lead is too soft. The zirc will mill a batch in one hour but I usually give it two. Lead used to take four to eight hours for the same performance and every time I ran the mill the balls came out a bit smaller.

 

I have 3 pounds of media in each drum - takes up half the volume, same as 5 pounds of lead - and mill 200g (8 ounces) batches. The mill can easily turn two 3 pound drums but can only manage one with 5lb lead media.

 

I have maintenance problems, the main one being the belts. I replace the floppy rubber belt with a polyester reinforced cogged V belt, Dayton 13V773, which is actually available at Walmart believe it or not - http://www.walmart.com/ip/DAYTON-13V773-FHP-V-Belt-Type-2L-1-Rib-13/40785500. It never slips, it never breaks, and once this is done you never have to worry about belts again.

 

Another annoying maintenance problem is the shafts and bearings. One of my mills seized up recently, and when I dismantled it to look at the bearings I found that the shafts are chrome plated, and the plating was flaking at one end. Bits of plating were embedded in the plastic bearing and seizing the shaft. I reamed out the bearing and rubbed down the shaft but it's going to happen again. When it does maybe I'll replace the shaft with steel drill rod and bronze bearings. I actually have the bearings, but I haven't replaced them because they need the end plate holes enlarged. These holes currently are keyholed and I can't drill them out and keep them concentric. On the other hand the cost of a new mill is less than I bill for one hour of my time, so I'll probably just buy a new one.

 

 

I have heard that ceramic kinds of media tend to crack and can leave traces in the chems like marbles?

 

EDIT----

Also, I live in Miami, FL - the humidity is closer to 200% most days than it is to 0%, how much of a factor will this play in my milling time/media/peak points?

Edited July 1, 2015 by Nickmaslo

[Ubehage]

 

 

I have heard that ceramic kinds of media tend to crack and can leave traces in the chems like marbles?

 

EDIT----

Also, I live in Miami, FL - the humidity is closer to 200% most days than it is to 0%, how much of a factor will this play in my milling time/media/peak points?

If you make sure to dry your chemicals and seal them properly, then it should not be any factor at all.

Humidity will only get to the chemicals, when they're exposed to the open air.

In that perspective, my experience is that KNO3 will absorb a few % of % of moisture really aggressive and fast. And from there on, it will absorb moisture much slower, But still, it will absorb any moisture present.

 

Coal will also absorb a tiny bit of moist over time.

[marks265]

I mill my lift and break powder for 2 hours. Comet compositions for 1-1/2hrs. If I run my mill too fast the powder and3/4" lead balls heats up and causes clumping and balling up issues. If this happens I slow the mill down and run an extra 1/2 hour.