How many hours do you ballmill your BP?

[Nickmaslo]

So zirc media wont crack, shard, or shrink when milling then? I found a source for zirconium spheres so just wondering if its worth the investment?

 

 

Sidenote from my first post - I did end up getting contacted by FPAG, I am going to the July 18th shoot up in Eustis, FL and bringing about 100 reloadables, so if that was anyone's doing here, thank you. The treasurer and I talked for quite a while and had a great conversation , an again - its an honor to be apart of this community.

[Peret]

The zirconia milling media I use is 4039GM-C12 - I was lucky enough to get 20 pounds used for $50. Here's the web site -

http://www.advancedmaterials.us/zirconia.htm

It is purpose made for milling hard materials and it doesn't chip, crack or wear.

[BeverFever]

I use 200 .45 cal lead shot and a few extra egg shape fishing weights in my stock HF mill. I tried 6 hours, but that wasn't enough to lift my 2" 140g shell. So I just mill my powder overnight now, or until it clumps. It has produced great lift for my recent 3" shell ( sort of, it was 2" tall, 3" diameter) at 240g. I used 34g of lift to be on the safe side, I think it was too much, 24g would have worked fine.

[oldspark]

I have read and I agree with it that once the BP is ground very fine it will pack and clump, Lloyd's book talks about clumping and the temperature having an effect on the clumping. I ball mill for 1.5 hours and it is not clumped and works great (ned has found the 1.5 hours to be correct for him after testing different times).

There are more reasons for it to clump then just moisture.

[insutama]

so when my powder clumps is it done or should I open the mill and bust it all up then mill it more ? Mine seems to burn super fast faster than goex ffff but I have never tested it with a baseball I only have smaller mortars is there a other way to test how good your powder is with smaller mortars ? It seems to launch my little ballshells decently I use about 15% of the ballshell weight in black powder and it seems to work fine.

[Ubehage]

I have read and I agree with it that once the BP is ground very fine it will pack and clump, Lloyd's book talks about clumping and the temperature having an effect on the clumping. I ball mill for 1.5 hours and it is not clumped and works great (ned has found the 1.5 hours to be correct for him after testing different times).

There are more reasons for it to clump then just moisture.

 

I agree to that.

From the physics I know, I would expect an extremely fine powder to act like a liquid, untill it reaches a state of even finer powder, at which point it will start clumping.

Coal especially this, since each atom doesn't like to be "all alone". It will happily bind to other atoms (all elements, some of which you don't even have to spend any energy on doing so).

 

Fun fact: This is also the reason why all life on Earth is carbon-based; it's the element with most varieties in chemical bindings, and can release relative small amounts of energy with minimal effort.

[wizard7611]

I ball mill my normal 75/15/10 black powder for 6 hours. After every two hours, I tap on the sides of the containers to knock off the black powder that might have been stuck to the sides. However, when I have normal 75/15/10 black powder with 10% or 20% dextrin, I ball mill it for 48 hours, as well as tapping the sides every 6 hours.

[Arthur]

... However, when I have normal 75/15/10 black powder with 10% or 20% dextrin,...

 

10 to 20% dextrin???

[Nickmaslo]

That is A LOT of dextrin. I use 3%-5%

[wizard7611]

 

10 to 20% dextrin???

10% for granulating black powder and 20% for black match. Don't ask me where I got this from. My source was Cannonfuse.com.

[Ubehage]

10% for granulating black powder and 20% for black match. Don't ask me where I got this from. My source was Cannonfuse.com.

Try with 4%

And go down to 2%, if you dissolve it in the water you use to bind it.

[stix]

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

 

Yes, I've experienced something similar... I think. Not cracks but tiny chips. I'm not concerned about chemical traces though.

 

I believe my media is "Alumina Ceramic". About 10% look like they have tiny chips. I think the reason is that when I was first experimenting, the mill jar was "undercharged" and also spinning too fast. Meaning that the media wasn't grinding properly but falling down and smashing against each other.

 

I did get some advice on this forum regarding issues with "undercharging" the mill, and possible "ball media wear" - but I didn't think that this applied to me, partly because I like to do things my way, but mostly due to the ceramic media I was using. I thought that the ceramic balls were like "Superman". It seems that original advice has been validated. I think Zircona media is stronger? so I'm not sure if wear would be an issue.

 

Anyway, I have a small jar of around 3/4 litres, which holds approx. 45 x 20mm (3/4") ceramic balls (half full) - so 10% chipped equates to 4-5 balls. I'm really not sure if the chips were always there. Regardless, I don't undercharge my mill anymore.

 

For the record, and in answer to the ops question, I ball mill my bp for around 5hrs. That's with "pre-milled" kno3.

 

Cheers.

[greyhawk]

Hi guys

I milled my first batch 12 hours - it came out like talcum powder - no clumps - that was fresh burnt charcoal, fresh opened bags of KNO3 and Sulphur - I thought I had my stuff stored good - charcoal in a sealed plastic container, the others in the barn in original bags stashed in plastic storage boxes - its been damp weather here (winter) and now my stuff (fourth batch) is clumping in the mill - I have cut back to six hours running time, but it will be lumped up in the mill at two hours running. Used all my charcoal so next batch will get really well sealed and may use the calcium chloride as well. Will dry the KNO3 and sulphur in the house before I make each lot from now on. I reckon if it lumps in the mill the stuff has got damp. Happy with my result so far - I won three prizes at a regional rendevous shoot last weekend with a rifle I build myself and powder I made at home. Need to get more density in it to use in brass cartridges but it works in the muzzleloaders. Am about halfway between chinese powder and Goex in oooomph per weight but mine is more bulky. Have learnt lots of interesting stuff so far - no ball mill = fizz, fizz, splutter, splutter ..... ball mill it to flour = ka boom !

Greyhawk

[wizard7611]

Try with 4%

And go down to 2%, if you dissolve it in the water you use to bind it.

Yes, I've already restarted on that end of it.

[Ubehage]

Hi guys

I milled my first batch 12 hours - it came out like talcum powder - no clumps - that was fresh burnt charcoal, fresh opened bags of KNO3 and Sulphur - I thought I had my stuff stored good - charcoal in a sealed plastic container, the others in the barn in original bags stashed in plastic storage boxes - its been damp weather here (winter) and now my stuff (fourth batch) is clumping in the mill - I have cut back to six hours running time, but it will be lumped up in the mill at two hours running. Used all my charcoal so next batch will get really well sealed and may use the calcium chloride as well. Will dry the KNO3 and sulphur in the house before I make each lot from now on. I reckon if it lumps in the mill the stuff has got damp. Happy with my result so far - I won three prizes at a regional rendevous shoot last weekend with a rifle I build myself and powder I made at home. Need to get more density in it to use in brass cartridges but it works in the muzzleloaders. Am about halfway between chinese powder and Goex in oooomph per weight but mine is more bulky. Have learnt lots of interesting stuff so far - no ball mill = fizz, fizz, splutter, splutter ..... ball mill it to flour = ka boom !

Greyhawk

 

KNO3 will absorb moist through the tiny openings in most plastic containers.

You need to get a tight closing lid.

[Nickmaslo]

Does perchlorate act the same way as nitrate in regards to its sensitivity to atmospheric humidity?

[insutama]

perchlorate is not hygroscopic kno3 is hygroscopic

[greyhawk]

 

KNO3 will absorb moist through the tiny openings in most plastic containers.

You need to get a tight closing lid.

Yeah .. I figured it was the KNO3 ,, have got some screw top containers and will re-dry the stuff in the house before I store it away.

[starxplor]

The zirconia milling media I use is 4039GM-C12 - I was lucky enough to get 20 pounds used for $50. Here's the web site -

http://www.advancedmaterials.us/zirconia.htm

It is purpose made for milling hard materials and it doesn't chip, crack or wear.

 

Is zirconia media as safe as lead for milling BP?

[TYRONEEZEKIEL]

Yes it is. It is safer I believe as you do not have to deal with the toxicity of lead.

[braddsn]

Thumler's tumbler (Model B high speed) 1,200 .50cal lead balls, 1kg of bp at a time, I mill for 3 hours. Every now and then I get clumping. Probably because it is 4 million percent humidity here during the summer. But my bp is consistent.

[TYRONEEZEKIEL]

Brad. Your mill doesn't sound like it's optimally charged

[braddsn]

Tyrone, expand on that if you don't mind? Do you think I should add more media? (I actually run 2 Thumler mills by the way). I started with 1,300 balls, but it seemed to overwork the unit a little. I didn't want anything to wear out prematurely so I took some out. Do you run a Thumlers? I can certainly put more media in.. I have about 1,000 lead balls on standby. I get very fast bp after a 2 hour mill run, but I usually run bp for 3 just to be on the safe side.

[Arthur]

IMO I'd assume that if the powder is good then the mill MUST be ok, and if a 3 hour mill time is good then it's not a lot of value to reduce that by even 10%.

 

I'm usually happy to over fill my mill slightly. The mill goes on when I leave for work and goes off when I return home so it copes with over filling

[TYRONEEZEKIEL]

Brad, according to Lloyds ball milling book you should half fill your jar with media and quarter full with powder. A thumlers is a 5qt mill and needs to spin at 65 rpm. Unfortunately you are overcharging your powder. From my calculations, you can run 24 oz of powder or about 672g. I calculated around 1400 lead balls. The plus side to you getting your mill to these specs is that your BP will be finished in 90 minutes. A mill of that size running efficiently will make maximum power BP in only an hour and a half.