BP Processing question

[Swede]

Question for you guys - it seems that there are so many ways to process BP, and they are all starting to blur a bit in my mind. I just made a killer batch of BP (meal) in my ball mill, mostly for use in rockets, so I milled in maybe 3% red gum, per Sleeter. So now I've got this nice flour-fine meal powder. But I'd like to use the powder for other things too, like mortar lift, and maybe break.

 

My question is this - is it best to store the new BP as meal? From there, I can

 

1) Use the meal as-is for Rockets or rice hulls; or...

 

2) Further process the meal; grain it directly from a hand-kneaded dough, or pressing it to pucks after moistening, then turning the pucks into pulverone and finer.

 

Or more likely, from what I've read, simply press the whole batch, and saving the dust from corning, using that as "meal."

 

I can make the BP now, it is what I do with it next that has be a bit baffled. I guess the next step depends upon what I want the powder to do for me!

[justanotherpyro]

I usually just store meal and then when I want some more lift I corn some more. If I want to make shell filler then I just use straight meal, same thing if I want to make BM. I usually try and store around a kilo or so in a plastic coffee can with the snap tight lid.

[Bonny]

I usually store "general purpose meal" made with SPF (spruce/pine/fir) to use for blackmatch, in fountains,as star prime and coating burst (in my case vermiculite).

For lift I make willow (or alder when Tentacles has the chardcoal) which is then pressed and corned. I use all the -20 +40 mesh stuff as my main burst for 1" cylinder shells and everything that passes I use as filler in shells ,mines etc.

[Swede]

Thank you guys, that does answer my question. I'll plan on storing the bulk as milled meal powder.

[hst45]

I keep a stock of milled meal on hand, and use it either as-is for blackmatch, fuel for endburner rockets or make it into lift by wetting a slug of it into a dough-ball and screening it through a 10-mesh screen into BP. I don't bother with the pressing-a-puck, crushing the puck, screening the granules, etc. process, and for me I works fine. Others will disagree, but that's my process.

[InRainbows]

How do you guys store your meal? I stored around 50 grams of meal in a bottle with a screw-on cap. It got gradually slower, same thing happened to a little flash I had in one of these bottles for storage while making cake inserts.

[justanotherpyro]

Did it maybe absorb moisture? Usually when I store BP in those flimsy containers ( cottage cheese, yogurt cups, whipped cream etc...) then it will slow down a bit but drying it out usually fixes it.

[Swede]

I bought a slew of those 1 quart and 2.5 quart paint buckets with lids at the local big box store. For larger batches and super long-term storage, the 2.5 gallon paint buckets have lids with rubber gasket seals. I've been bagging the stuff first into an oven bag (good, high-quality plastic), sealing with a twist-tie, and then putting the bag into one of those buckets with the lid. Hopefully, the double-seal should keep things fresh.

 

I think perhaps a better way would be to bag, then put the bags into a surplus ammo can. Those ammo cans are designed to be 100% weather and water-proof, and they do work well.

[InRainbows]

justanother, I got that much, it's just that these are a few containers i got empty when i used to order from unitednuclear.com. I thought that just dumping the powder in there would be enough. I guess I'll get me some twist ties and plastic baggies. Was just wondering if it was just me. Thanks.

[marks265]

I keep a stock of milled meal on hand, and use it either as-is for blackmatch, fuel for endburner rockets or make it into lift by wetting a slug of it into a dough-ball and screening it through a 10-mesh screen into BP. I don't bother with the pressing-a-puck, crushing the puck, screening the granules, etc. process, and for me I works fine. Others will disagree, but that's my process.

Thanks for the reminder hst45 I was just starting to forget about your method I think usually called granulating or ricing. I still want to try that for myself just to compare to the way I make mine now. I won't be happy until I try it for myself 'cause then I'll know what works for me!

I am still not done with my shellac issue either, so fair warning to all

[FrankRizzo]

I dampen, press, corn, and grade my BP by mesh size for lift powder, and rice my BP rocket propellants through aluminum window screen after dampening with straight water (no dextrin).

[hst45]

Thanks for the reminder hst45 I was just starting to forget about your method I think usually called granulating or ricing. I still want to try that for myself just to compare to the way I make mine now.

Take a look at the vid's I've posted on Youtube of some of the shells I've shot. I use 10% of the weight of the shell as my lift with my "riced" BP. It's plenty energetic for me, and it saves a bunch of steps. I shoot small stuff, 2", 2-1/2", and 3" ball shells so I can't comment on how it would work on larger shells. I just posted a 3" shell in the competition section for example:

[marks265]

hst

 

do you use 75-15-10?

 

I want to try that and one or two adjustments. Then maybe see how dextrin might affect it. Lastly will be to lay it in my burn trough and see how fast it. Then decide on one and launch a 3"er or 2 or 3

[hst45]

marks,

 

The lift in the video was in fact 75/15/10 + 2-1/2% dextrin, ball-milled 12 hrs. The charcoal was beech, roughly crushed then ball-milled 24 hrs. I then wetted this into a dough ball with 25% ethanol / 75% water. To each his own, but this works for me. Good luck.

[Swede]

2) Further process the meal; grain it directly from a hand-kneaded dough, or pressing it to pucks after moistening, then turning the pucks into pulverone and finer.

Oops, I think I made a mistake here. PyroGuide describes "Pulverone" as the powder you get when you take freshly-milled BP, moisten it, then screen the dough into granules. Is this correct? I earlier thought pulverone was the very coarse stuff you get when you break up pressed BP pucks.

 

Which is correct?

[TheSidewinder]

Polverone is one of those words that's taken a very broad meaning.

 

I believe it originated in Italy, and had a sharply-defined meaning at the time. But no longer.

 

The large chunks from corned BP would, I think, be too "strong".

 

I know someone who makes his own polverons, and large quantities of it, using only screened raw ingredients, aka Green Mix, wetted and pressed through hardware cloth.

 

I remember him saying it was used primarily as a filler and a way to make sure everything in the shell simply gets lit.

 

While it ADDS to the burst, it's not intended to BE the burst, at least as far as he's concerned.

[Mumbles]

I think Sidewinder is talking about someone else, but I do almost the exact same thing as he's talking about. Filling in the spaces between stars with the stuff makes rock hard shells. You'd swear I was using carpet cores as the canister shell casing from how hard they get. I have found it greatly improves my symetry and break strength.

 

I use a center canule of good fast granulated powder. I add about half a canister full of stars, and add in some of the granulated green meal. I then tap the side of the shell with a wooden dowel. I think I've posted a picture of my magic shell closing device before. It all settles, the stars will move to the top, and the powder will flow down. Keep checking the firmness of the sides, and adding powder as needed. It will start getting very hard. I will then fill it to a bit below the rim, and repeat. You want to aim to end about 1/4" below the rim of your liner(if you use one). I then add a layer of coarse polverone over the top to make a flat surface for the disk to lay against. I usually pack the stars in first with polverone, and add the lift last.

 

http://www.apcforum.net/Mumbles/Pics/tmpABB-9.jpg

 

I screen the powder through a 6 mesh screen when wet. What passes 6 mesh, and is retained on a 24 I keep for the filler between stars. What stays on top of a 6 mesh screen I use for the last coarse polverone fill. You want the coarsest stuff, so it won't migrate down into the stars too. What passes 24 I use for priming comets, fuses, etc, and to use as a filler in small inserts.