Granule Size for Shells?

[OblivionFall]

Hi there, I am almost ready to make my first "good" batch of BP. I have a few questions:

 

What granule size is optimal for:

 

• Lift BP?

 

• Shell Break Powder? (I'm not sure if it's called Meal powder. I was considering BP coated rice hulls or something like cheerios coated with BP.)

 

• Fountains?

 

• Rockets?

 

I would assume that fountains, rockets etc. may use different ratios of chemicals as apposed to the 75:15:10. I want to know which granule sizes would be optimal for each of these.

 

And Also: How long should I mill my BP for? I heard that TT stars (considering that they have a different mixture) take 4 hours while hot BP takes 8.

 

Thanks

Edited May 6, 2015 by OblivionFall

[pyrokid]

Lift BP varies in size depending on shell size. Granule size increases with shell size. I don't know mesh or micron numbers, but hot BP granulated through a window screen has always served me well.

 

Mill dust is generally used to coat bursting media. Don't forget the dextrin. Unmilled 75-15-10 powder is processed into pulverone/polverone for use as a combustible filler in traditional canister shells.

 

Granulation of powder destined for rockets or fountains is generally only done to improve flow characteristics and reduce dust. Size isn't critical as long as it can be compressed into a solid grain.

 

Some people prefer unmilled TT stars. The effect changes with milling time. I mill my BP until it looks fast enough. Everyone sees different times due to different mill characteristics.

[braddsn]

Oblivion, 4FA is good for lift until you get into 5" shells or larger. A 20 mesh screen is what you need for this. For burst, meal coated rice hulls, or meal coated rice puffs are the way to go. I use rice hulls, at a ratio of 7 parts bp to 1 part rice hulls. In other words, I use 145g rice hulls and 1kg bp. The time it takes to mill black powder largely depends on the mill you have. A smaller mill (like a 6lb HF mill) will take 4-6 hours. A larger mill (like a Thumler's tumbler) can make hot bp in 2 hours. This has to do with the shape of the mill jar, size, and power of the motor. I mill TT stars for 30 minutes, in a Thumler's mill. In a smaller 6lb mill, it might take 45 mins or 1 hour. Also note: a good hot bp will only be made with a good reactive charcoal. Most of what you do in pyro will benefit from good reactive charcoal.. everything from bp to prime to charcoal stars.

[OblivionFall]

The closest thing I can find in stores to rice puffs is the cereal Rice Krispies hopefully it works just as well. By 6lb drum do you mean 2x3lb drums or one big 6lb drum? I'm working with a single 3lb drum. I estimate that 8 hours of milling will give me good results. Does this mean that for tTT Stars I'll have to mill it for 1 1/2 - 2 hours? I'll be using pine wood for stars and some other soft wood for BP.

[Mumbles]

If you can't find puffed rice cereal at the store, have you consider just trying harder or looking at more than one store? Typically it can be found in the generic cereals. Rice crispies are not the same, and don't work nearly as well.

 

I needed between 8 and 12hr to make good BP in my mill when I was using a stock harbor freight 3lb model. For me, it mostly depended on how fine everything was to start with. Coarser materials took a little longer generally. 12hr was probably overkill, but it worked.

[coogan1997]

Thats quite a long time. What about the 6Lb hf mill with the mods on the skylighter article ( increasing the rpm )?

[nater]

I mill BP for 2 hours in both my modified tumbler from Harbor Freight and my larger mill with similar results.

 

By the way, the 6lb version from HF is just 2 of the 3lb jars side by side. There is some dispute in if they share the same motor or not.

[OblivionFall]

If you can't find puffed rice cereal at the store, have you consider just trying harder or looking at more than one store? Typically it can be found in the generic cereals. Rice crispies are not the same, and don't work nearly as well.

 

I needed between 8 and 12hr to make good BP in my mill when I was using a stock harbor freight 3lb model. For me, it mostly depended on how fine everything was to start with. Coarser materials took a little longer generally. 12hr was probably overkill, but it worked.

Well darn...

 

at least I have some good cereal to eat

[OblivionFall]

I mill BP for 2 hours in both my modified tumbler from Harbor Freight and my larger mill with similar results.

 

By the way, the 6lb version from HF is just 2 of the 3lb jars side by side. There is some dispute in if they share the same motor or not.

So how long would you recommend I mill my BP for in a 3lb Lortone Rock Tumbler with some lead-antimony hardened balls? It doesn't spin very fast, a bit slower than the video here https://www.youtube.com/watch?v=B2mh5KFEbi8 (skip to 8:30)

[pyrokid]

That's funny man I was going to comment on what a shit video that was, and then he took out the glass marbles.

[OblivionFall]

That's funny man I was going to comment on what a shit video that was, and then he took out the glass marbles.

Yeah... I mean marbles with Black Powder is one thing but marbles with aluminum powder? The marbles must be done after a couple days...

[MrB]

One does not, under any circumstances, use glass-marbles for milling media. Ask BB, he knows.

B!