Help with Ballmilled Black Powder

[Col]

Well, I've been running if for 3-4 hours. Do you think that's long enough?

 

No overly scientific but take a small test sample from the mill jar every hour, At some point, you`ll reach a point of diminishing returns where the extra milling time isnt worth what you gain.

For milling individual chems, if it passes a 325mesh screen i would call it done

Edited September 9, 2013 by Col

[Dodad]

You'll know it's airfloat when you pop the top of your mill jar and release a black cloud of charcoal dust. Would be wise to wear a respirator or dust mask.

 

I mill prilled KNO3 for one hour by itself before mixing and milling into BP. My cooked Paulownia charcoal is also milled for no more than one hour by itself.

 

What size is the media in the picture?

[chemtech89]

I don't want to go out to my shed to measure. What is the inside diameter of the mill jar 4.5"? If so, using your .5" milling media the speed of the jar rotating on the rollers should be 86 RPM. For right now don't go nuts trying to get to 86, if its close it will be much better then stock. Also, I do suggest only using one jar at a time if you have the 6lb Harbor Freight model. Only because mine cant handle two reliably. With mine, it will rotate but becomes very likely to jam up and stop running causing the motor to get hot and melt the plastic mounts. Also, there is the potential for fire. With pyrotechnics you always want to think safety and plan for worst case scenario.

 

You increase the speed of your ball mill by increasing the size of the drive roller. If you have a rubber hose that will slide firmly around the drive roller without slipping when it rotates, use that. If you still need more speed, you could build up the size more by wrapping some electrical tape around it as an example. With that set up it takes me 12 hours to make hot ( hot; meaning powerful) powder. It might get there in 10 but with my schedule its easier at 12 hour increments. As mentioned before, there gets a point where the powder doesn't get any hotter (more reactive) and just wears down the media and jar.

 

Id say for right now just make sure everything goes through the mesh size of a windscreen and put it in the mill(some will disagree). After the mill has run for 12 hours separate the mill powder from the media with a screen again. As a test, take that mill powder and run it through the finest screen you have and see if there is any bits that sit on top of the screen. If anything sits on top then you know you need to go finer with whatever chemical that is, but I doubt there will be any unless its little piece of lead from the media that has chipped off.

[dan999ification]

I mill at under 75 rpm, after 2 hrs its more like 45 rpm ( battery ) in a 4" jar.

I do start with fine material though After 3hrs the bp lifts and breaks adequately for my needs, test hourly.

 

Dan.

[dynomike1]

I dont mill anything separate as far as BP, i also don't make charcoal. In a harbour freight mill i put 50 1/2" lead balls with 8oz. of comp. That would be 75/15/10+5% dex.. Run till it starts rattling pretty good. Take it out add water (make a ball) run it through a 1/4" screen let dry. Then you have granulated BP. That would be Paulownia Charcoal. If you want Pulverine run it through a window screen. I only use Pulverine in canister shells to fill the voids. For stars don't use Paulownia It is to hot. Use Airfloat. If you want Paulownia contact Algenco.If you have chemicals that is clumped up pretty good buy a $25.00 coffee grinder, don't get a Mr coffee, it wont last. Grind chemicals separate. At this point there was more info. put out than you needed, this time last year i was at your stage. I know how confusing it is. Edited September 26, 2013 by dynomike1

[Bobosan]

What size is the media in the picture?

 

Media size is .600 (15mm) hardened lead. All BP runs using premilled components is 4 hours.