How do you know when your ball-milled black powder is "done"?

[Kaokin]

So my first ball mill is nearing completion, and with everything that I have read, there is a huge variance among fireworks enthusiasts as to how long they mill their powder. I know that this depends on a variety of factors, but how do you tell when your black powder has reached its maximum strength? How do I know when to stop milling?!?!

[dan999ification]

hi,

i take a sample from different stages in the milling and burn it to see how its getting on

and if its no longer improving then stop. [good bp can be made quickly] a camera helps to remember previous batches speeds, i only test small amounts and depending on what i want the bp for, for fillers and primes i dont really worry too much about it being super fast but for my lift i go all out .

for lift i want to see the meal powder go "poof" when lit

and for filler a "whoosh" will do me.

corning it will also improve its speed if your worried about using it for lift.

there should be no slag leftover

there are better ways to test it but when its fast you'll know

 

 

Edited April 27, 2011 by dan999ification

[50AE]

Black powder cakes when it becomes very fine. I know when it's finished by the sound change from my ball mill. It's a "dry" media knocking sound, meaning no material is milled.

[dagabu]

I agree, an efficient ball mill using dry chemicals will reduce the comp to the clumping condition in very little time, though I do break the clumps once and regrind for 15 minutes just to be sure

 

-dag

[Mumbles]

The only way to know for sure is to take samples and test them. In my small mill, it happened that the clumping and done stages pretty much were at the same time. In my larger mill, it clumped well before it was done. You can't always take that as a definitive sign.

[Kaokin]

Ok Gotcha.... How exactly are you "testing" the powder in various stages of milling? I am new to milling so I dont want to rely on a subjective "poof" or "whoosh" determination until I am a bit moer experienced. I have read about the timed baseball method, but that kinda seems like a PITA. I will probably use this method only for testing the finished lift powder grains, but that doesnt help me determine the quality of the mill dust...

 

 

[dagabu]

Dan C. has taken a lot of the trouble out of testing BP and has some excellent tutorials for testing BP power HERE.

 

-dag

[FrankRizzo]

Ok Gotcha.... How exactly are you "testing" the powder in various stages of milling? I am new to milling so I dont want to rely on a subjective "poof" or "whoosh" determination until I am a bit moer experienced. I have read about the timed baseball method, but that kinda seems like a PITA. I will probably use this method only for testing the finished lift powder grains, but that doesnt help me determine the quality of the mill dust...

 

Kaolin,

 

I use the 1/4"x2" tubes available from Pyrocreations or Cannonfuse.com. I place a small piece of masking tape over the end of the tube to seal it, and use a nylon-faced hammer to ram enough increments to create a powder column just over 1" in length. My increment measure is an empty .22LR cartridge glued to the end of a thin wooden stick. Each increment should be hit with exactly the same amount of taps with as close to the same amount of force as possible. Then, I use a 1/4" drill bit turned by hand to remove the excess powder until the column is exactly 1" (use a caliper). Remove the tape, use a video camera to record the burn, and count the number of frames it takes from ignition to flame coming out the other end of the tube. I test a small sample of powder every hr during milling, and consider my powder to be "lift-worthy" if it burns within a few tenths of a second of 2sec or less.

Edited April 29, 2011 by FrankRizzo

[DdDodd]

I followed Ned's article on Skylighter when I ball mill, but being a noob, not sure if I should stick to this process or not. I use 6" PVC jars filled with a 20oz charge, mill for one hour, then use it for burst, lift, etc. So far, only milling for one hour works fine for lifting my 4" shells(i use 1.75oz) as well as coating the rice hulls for burst. Compared to consumer 1.4g aerial shells, the boom isn't as loud, but the burst is fine and the shell lifts nicely. Only thing I can think or that I would gain by milling longer is a louder break, but correct me if I am wrong, still new to this.

 

http://www.skylighter.com/fireworks/how-to-make/tiger-willow-ball-shells.asp

[Seymour]

Other than louder, you could expect it to be wider and more symmetrical.

 

It's all dependent on what you prefer. Some shells I like to break really hard (as in, that shell of yours would also have five grams of good flash), while on others, I'll only sprinkle enough BP (maybe five grams) to ignite the effects, smash it open and dump the effects.

 

So if you're getting just what your after with the current powder, then there really is no point milling the powder longer (other than the fact that you could use less BP on the hulls, but get the same effect.

[Algenco]

I don't understand why everyone feels the BP for break must be boosted unless it's just for the extra noise?

Especially with FP, the brightness detracts from the effects IMO.

 

Granulated BP or coated Rice hulls made with reactive charcoal works fine without enhancements.

 

I prefer salutes to be seperate from display shells

[50AE]

I agree with Algenco, I hate the flash from many commercial shells.

[Peret]

Me too - I don't boost my shells and I get good breaks.

[dagabu]

I don't understand why everyone feels the BP for break must be boosted unless it's just for the extra noise?

Especially with FP, the brightness detracts from the effects IMO.

 

Granulated BP or coated Rice hulls made with reactive charcoal works fine without enhancements.

 

I prefer salutes to be seperate from display shells

 

Boosters are needed in small and plastic shells due to the propensity of the shell materials rupturing prematurely and making ugly breaks. There are few that can get perfectly round breaks from small plastic shells and those that do use flash bags or booster to get the job done.

 

I do agree that hard breaks distract from the shells beauty but when launched from on top of a rocket, a 4" canister shell needs a good boost to make a viewable spread at 600-700'.

 

Just my opinion though, do as you all wish, as long as it is pyro, it's good in my book.

 

-dag

[Peret]

3 inch plastic shells, just 4:1 BP on rice hulls with no booster.

[Seymour]

Ah, the age old "to boost or not to boost" argument.

 

-With good flash, and not too much of it, there is negligible increase in brightness as the shell bursts. You get that from adding way too much flash, or slow flash (so the reaction is not complete when it opens), or by using flash only as the burst. The mixture of a bit of flash and plenty of BP seems to do an excellent job of mopping up any Al that might otherwise afterburn.

 

-If your BP gives the answer you want, then great. I went through a phase where the neighbours and family hated the ball mill so much that I milled my BP for 1.5 hours, and compensated with flash booster.

 

-I don't find a moderately flash boosted shell any louder than a shell that bursts the same diameter and uses KP, H3 or really good BP. For some of us, BP + 2g flash is cheaper than KP burst charge.

 

-Boosting does give more power, and this means you can pack more effects in to the space that you would otherwise have had to put just burst. This means you can double the pistil stars, for example.

 

 

I will admit that the argument that flash will cause a detrimental blinding flash to your shell's burst does annoy me somewhat. I'm not denying that it can do so, but I have a very strong feeling that most people who say this are making up their mind based on some shells they've seen that have this phenomenon, and then class all flash boosted shells like this.

 

Just not (necessarily) true.

 

I'll just add as a final point that I agree that some shells are much nicer with a denser burst, and that gives them a special beauty. Other times I can't deny I want a huge burst (more often the brocade-type shells).

 

 

No flash in that shell

[dagabu]

Ah, the age old "to boost or not to boost" argument.

 

-With good flash, and not too much of it, there is negligible increase in brightness as the shell bursts. You get that from adding way too much flash, or slow flash (so the reaction is not complete when it opens), or by using flash only as the burst. The mixture of a bit of flash and plenty of BP seems to do an excellent job of mopping up any Al that might otherwise afterburn.

 

-If your BP gives the answer you want, then great. I went through a phase where the neighbours and family hated the ball mill so much that I milled my BP for 1.5 hours, and compensated with flash booster.

 

-I don't find a moderately flash boosted shell any louder than a shell that bursts the same diameter and uses KP, H3 or really good BP. For some of us, BP + 2g flash is cheaper than KP burst charge.

 

-Boosting does give more power, and this means you can pack more effects in to the space that you would otherwise have had to put just burst. This means you can double the pistil stars, for example.

 

 

I will admit that the argument that flash will cause a detrimental blinding flash to your shell's burst does annoy me somewhat. I'm not denying that it can do so, but I have a very strong feeling that most people who say this are making up their mind based on some shells they've seen that have this phenomenon, and then class all flash boosted shells like this.

 

Just not (necessarily) true.

 

I'll just add as a final point that I agree that some shells are much nicer with a denser burst, and that gives them a special beauty. Other times I can't deny I want a huge burst (more often the brocade-type shells).

 

 

No flash in that shell

 

Nicely said Seymour, a very well put explanation.

 

-dag

[stckmndn]

Seymour, that was a beautiful shell. What are those rising effects? I don't believe I've seen those before.

[Seymour]

Seymour, that was a beautiful shell. What are those rising effects? I don't believe I've seen those before.

 

Thank you

 

Timed ascending horsetails. Very easy to do. These are the kinds of shells where I fill them with stars completely, then sprinkle about five grams in, just to light the stars and pop them open. I wanted to use the momentum that they already had from being taken up by the main shell to give them direction.

Edited July 12, 2011 by Seymour

[stckmndn]

Thank you

 

Timed ascending horsetails. Very easy to do. These are the kinds of shells where I fill them with stars completely, then sprinkle about five grams in, just to light the stars and pop them open. I wanted to use the momentum that they already had from being taken up by the main shell to give them direction.

 

Are they attached to the main shell? I would assume so but don't want to guess.

[pyrogeorge]

If my bp is ready,first of all i make a test and i see how it burning,then i see for white dots from unmilled kno3..that's all

[Seymour]

Are they attached to the main shell? I would assume so but don't want to guess.

 

Your assumption is correct!

Edited July 12, 2011 by Seymour