How many hours do you ballmill your BP?

[dynomike1]

That might be true, but i run ceramic and i don't have any problems. When making BP i make 4lb. batches and run for 18hrs.

[deepdixie]

Apart from your chemicals containing moisture, ceramic ball media can also introduce unwanted moisture.

I use hardened .50 caliber lead balls for my milling media. I'm milling another batch this morning and the temperatures are relatively cool outside. I read in Lloyd Sponenburgh's book that higher outside temperatures when milling more often result in caking in the mill jars. Perhaps with these cooler temps it won't be such an issue. I'm also going to add the Dextrin in during the final 30 minutes of milling to see if this makes any difference.

[dynomike1]

What i didn't like about the lead is they wear out to fast.

[deepdixie]

I've been using the same 12% Antimony hardened lead balls for several years now and after milling quite a few loads, haven't noticed any reduction in the size of the media.

[dynomike1]

Yea mine was probably softer. I use wheel weights to make cannon balls but i don't have a 1/2" mold. My lead balls went down to 3/8 the first year, so a friend of mine recommended ceramic. But on the other hand you might not mill as much comp as i did that year. I start the fall off making a 5gal. bucket of BP and MCRH. As far as charcoal; streamers i still have plenty.

[MadMat]

Dynomike, is your ceramic media much lighter than lead as I would expect? Just asking because I have given ceramic media some thought, and I figure it is considerably lighter than lead; I figure this would increase required milling times. I feel a heavier media would crush/mix the material being milled much faster. My ideal media would be one of the aluminum bronzes used for bearings. The stuff is very hard and wear resistant, unfortunately it is also quite expensive

Edited November 14, 2015 by MadMat

[dynomike1]

My ceramic weighs any where from 8-22g. My lead went down to 10g the first year.

[Ubehage]

My ceramic weighs any where from 8-22g. My lead went down to 10g the first year.

Half of my lead balls decreased significantly in size, "just because" I milled some KNO3 that wasn't all dry.

Besides wearing on the media, I'm also worried about contamination of the milled KNO3.

It's only good for BP, since I don't know enough about Lead-incompatibilities.

 

I have switched to ceramic media. Besides being so much cheaper, they don't seem to wear out the same way.

I currently have an ongoing test: I filled the mill-jar with ceramic media and some KNO3 with a little water added. I will let it run for 2 days, then I will compare both the KNO3 and the media balls, to see if there is any contamination or wearing of the balls.

[stix]

I mentioned the potential for ceramic balls to attract moisture for a reason - they "absolutely will" absorb moisture under certain circumstances, and that particular circumstance in my case was washing and soaking them in water to clean them.

 

I found this out after having some clumping issues. I dried the media out in the oven at about 120C and was shocked!! - they became wet on the outside - absolutely wet!!!... after an hour or so they dried out.

 

"Clumping" when milling bp is a sign of too much moisture somewhere in the chain. Natural environmental humidity can make a difference, but not to the extent that it is so obvious to cause clumping (in my experience).

 

There are some very resinous charcoals that may not require a binder like dextrin or sgrs, but I doubt that this is a reason for clumping.

 

Make sure that all your chems (and ball media) are dry to the best that you can. There is NO bizarre, alien or other unknown reason. It is quite elementary - make sure your chems (and media) are dry.

 

Cheers.

 

[EDIT] Reason for editing: . . . // . . . known, or known unknowns, but likely very un-important.

Edited November 15, 2015 by stix

[DonCopal]

The clumping can occur because of the charcoal you use. The vineyard charcoal I used some years ago always clumped whereas the homemade alder buckthorn coal I use now does not clump at all under the exact same conditions.

[stix]

[EDIT] It's late here and I probably should review what was posted tomorrow. - I apologise if I seemed dismissive.

 

Cheers.

Edited November 15, 2015 by stix

[Mumbles]

High alumina ceramic, which is somewhat of the norm, weighs approximately half of what lead media does. As a slight aside, the grade of ceramic matters. We really should be using a high alumina (90+%) variety. There is concern lesser grades, which are also cheaper, are more prone to sparking. Much of the secondhand ceramic media in the US is of questionable or unknown origin and composition, which has always given be pause and made me hesitant to make a switch.

 

What ceramic loses in mass, it tends to make up for in hardness. It may not have quite as much inertia, but the chemicals are being ground between much harder surfaces. I'm not sure how much the mass really matters to be totally honest. With the many thousands of impacts per minute, most medias will get the job done in short order. It would probably make a difference for crushing large chunks, but once you're grinding microscopic pieces, I doubt it matters if the media is 1 million or 2 million times heavier that the particles. It's going to be smashed into oblivion either way.

 

Lighter medias have a use for larger mills. We as hobbyists probably think of batches between 2.5 and 5lbs as pretty big, and tend to be about as large as they come. If you need more, people tend to just use multiple jars of this size. That's not really how things work on a commercial scale. They use much larger jars, which requires lighter media to be handled. The place I'm most familiar with milled 25lb batches of compositions. You'd probably need a forklift to move around those jars if they used lead. Even with ceramic and being somewhat under charged, I think they were still probably close to 100lbs.

[starxplor]

High alumina ceramic, which is somewhat of the norm, weighs approximately half of what lead media does. As a slight aside, the grade of ceramic matters. We really should be using a high alumina (90+%) variety. There is concern lesser grades, which are also cheaper, are more prone to sparking. Much of the secondhand ceramic media in the US is of questionable or unknown origin and composition, which has always given be pause and made me hesitant to make a switch.

 

What ceramic loses in mass, it tends to make up for in hardness. It may not have quite as much inertia, but the chemicals are being ground between much harder surfaces. I'm not sure how much the mass really matters to be totally honest. With the many thousands of impacts per minute, most medias will get the job done in short order. It would probably make a difference for crushing large chunks, but once you're grinding microscopic pieces, I doubt it matters if the media is 1 million or 2 million times heavier that the particles. It's going to be smashed into oblivion either way.

 

Lighter medias have a use for larger mills. We as hobbyists probably think of batches between 2.5 and 5lbs as pretty big, and tend to be about as large as they come. If you need more, people tend to just use multiple jars of this size. That's not really how things work on a commercial scale. They use much larger jars, which requires lighter media to be handled. The place I'm most familiar with milled 25lb batches of compositions. You'd probably need a forklift to move around those jars if they used lead. Even with ceramic and being somewhat under charged, I think they were still probably close to 100lbs.

 

Another advantage of ceramic media's lower weight is that under powered motors, like un-modified HF tumblers, might last longer before burning out.

[50AE]

When I was ball milling in the past, I had a two drum 2*3 liter ball mill with PVC drums and lids. It was running a little bit faster above the optimal speed, but I had to change the pulleys to do so, so I left it alone. I needed at least 6 hours running both drums to get excellent BP. I milled the KNO₃ in the first drum and the charcoal/sulfur mixture in the other. Afterwards I mixed the reagents and put them to as a live composition to mix. For safety, I was removing 3/4 of my media to prevent large cascading action and only a mixing action.

[pyrohacker]

_{Having some issue with my media and bp. Mine clumps inside the barrel after 3 hours of tumbling. Any idea why is it doing this? Then it is hard to take the bp off the media. I use 0.54" lead balls. Please help! Here's a pic of it.}

Edited February 8, 2017 by pyrohacker

[Mumbles]

Moisture in your chemicals is the most likely culprit.

[OldMarine]

_{Having some issue with my media and bp. Mine clumps inside the barrel after 3 hours of tumbling. Any idea why is it doing this? Then it is hard to take the bp off the media. I use 0.54" lead balls. Please help! Here's a pic of it.}

Try drying your nitrate at 250°F for an hour or so before milling. I had horrid clumping problems before I started drying my nitrate before milling.

Edited February 8, 2017 by OldMarine

[Seymour]

And the charcoal may have a fair bit of water in it too, depending on the exact charcoal and storage conditions.

[OldMarine]

Seymour, I haven't found the need to dry my charcoal since I mostly make my own but you may be right on that. If one had the drying space to dry everything beforehand that would be ideal but I guess storing the individual chems with desiccants would be a good second.

I know for a fact that drying your nitrate helps with the clumping.

[pyrohacker]

Try drying your nitrate at 250°F for an hour or so before milling. I had horrid clumping problems before I started drying my nitrate before milling.

Ok I'll try it the next time but now I'm going to dry the whole composition since it's already mixed. Then I'll mill it again to see if its just it. I thought could be the dextrin in it too and the next time I'll add it after milling the bp first, then mill the whole composition for an hour.

[Mumbles]

How are you planning to dry the whole mixture? I hope not in an oven or something. Typically even my clumped BP burns well. It's annoying, but not detrimental to the BP as long as everything grind and mixes well.

[pyrohacker]

How are you planning to dry the whole mixture? I hope not in an oven or something. Typically even my clumped BP burns well. It's annoying, but not detrimental to the BP as long as everything grind and mixes well.

Obviously not in an oven. I'll dry them on the best and cheap light ever, the sun.

[pyrohacker]

Today I placed the bp for as long as three hour to direct sun light revolving it each hour. Then I placed the bp into the milling barrel for about three hours. Finally it worked as supposed to and it ended looking like bp meal. Looks just perfect!

[passgas]

Yesterday I did my first batch of bp. It was a gallon size 6" jar , 60 cal lead balls, 70 rpm jar speed. Weight wise finish product was about

1 lb 9 ounces. Mill time was 2 hrs. I was very happy with the results. I lit off a teaspoon which lit very easily and quick,

 

My next step is to research how to do some speed test for the powder.

 

I need to research how to granulate my powder.

 

More learning curve ahead but I am very happy with the results so far.

 

Forgot to add 1 lesson learned is to make sure vent is open on gas cap on generator.

Edited March 30, 2017 by passgas

[calebkessinger]

Lots of us do baseball testing out of a 3in. mortar.

It's easy to time the flight and see where you are at.