Corned BP Lift vs "Pulverone"

[swervedriver]

Hi all, I have a question I'm hoping to get some advice for regarding lifting 5 and 6 inch round shells. Is there a significant increase for the chance of flowerpotting 5-6 inch shells when using hot riced lift (3 mesh) vs 2FA corned BP? thanks Edited March 27, 2010 by swervedriver

[swervedriver]

Hmmm,anyone? Has anyone lifted 5 or 6 inch paper/plastic round shells with granulated black powder? Trying to avoid corning the lift powder for mid-sized shells.

[TheEskimo]

At the very least, I would make your polverone grains larger. Or you could go with really slow polverone, and use 1/10 the weight. I get worried using my really hot stuff....I make the grains small, due to the size of my screen, and as a consequence I use about 1/16-1/18 the weight. This is just with 3 and 4inch shells. But with the bigger shells, you want slower lift. So I would suggest making slow polverone, with large mesh grains.

[Mumbles]

You'll be fine with 3 mesh polverone, assuming you're talking about granulated milled powder. I've used 1Fg commercial powder, which is about equivalent to 4FA. It really fires out of there. Honestly, with ball shells, I'd be more worried about destroying the gun instead of flower potting the shell.

[qwezxc12]

Hmmm,anyone? Has anyone lifted 5 or 6 inch paper/plastic round shells with granulated black powder? Trying to avoid corning the lift powder for mid-sized shells.

 

 

Like Mumbles said, I think you'll have no problem. No need to press and corn. For lift I use standard 75:25:10 made with Alder charcoal +1.5% CMC milled in, dampened with ~20% water, and riced through a -8ish screen while damp.

 

After drying the CMC grains are very hard and durable. I screen the lift grains and get approximately 60% 4-12mesh, 35% 12-24mesh, and <5% +24mesh. I use the largest grade for lifting 4-8in shells, the 12-24mesh for lifting smaller shells and comets, and the +24mesh for piping fire, priming, and other misc uses. I lift 6in ball shells and 4-5in cans with 1/16th their weight in lift, 4in and smaller ball shells, salutes and small cans with 1/14th.

[swervedriver]

Great, I hoped to hear that. Thanks for the help.

[insutama]

Im confused what is polverone isnt all black powder meal granulated isnt this what makes it black powder ? or does polverone use no binder just water and black powder meal wouldnt this be very brittle and dusty ?

[Nessalco]

insutama,

 

Both corned and Riced BP are made from mill dust. Riced BP is mixed with binder + liquid, forced through a screen, and allowed to dry. Corned BP is mixed with water, pressed into pucks with a density of ~1.7g/cc, then the pucks are broken to smaller grains. Corned BP is denser, and tends to burn more evenly and less aggressively that hot riced powder.

 

Kevin

[nater]

Polverone is screen mixed BP, usually the standard 75/15/10 formula with dextrin. It is not milled and does not need to be made with a hot charcoal. The purpose of polverone is to make a flammable, non-compressible filler used in cylinder shells. It is used to pack the triangular shaped space in between stacked comets or insert and the shell casing. It is also sifted around stars to ensure they are solidly packed. In some cases it is used when a very soft break is desired.

[insutama]

ahh okay thanks for clearing this up the reason i was asking because i am trying to figure out what to use as a burt charge in my small 2" shells. I would have thought you would want fast burning powder to get a good break so why do people use polverone isnt that much slower than regular black powder or even rice hulls

[Mumbles]

It is much slower. A lot of people use the term polverone in ways that can be confusing and muddy up what they mean. The terminology as passed down from older generations is also somewhat mixed depending on where they came from and who they learned from. For a shell break, you'll usually want hot BP in a coarse form. For cylinder shells, this is usually granulated or corned material. For ball shells, this is often BP fresh out of the mill coated onto some sort of burst media like rice hulls, cotton seed, puffed rice cereal, etc. For small ball shells, some will use a granulated or corned black powder to not waste any space on inert components.

[insutama]

ah okay sounds good so making meal covered rice hulls actually slows the powder down ? For my small ball shells could i just use the same black powder i use for rockets which is the normal 75 15 10 but with no binder just dampened with 99% alcohol to make a ball then pushed threw a 10 mesh screen and let dry or should i mix in some dextrin and granulate with water ?

[nater]

I have heard the term polverone used to refer to any BP that was dampened and granulated rather than corned. I believe I read it being g used this was in some of the Maltese building articles published through the Florida guys on Passfire. Most builders I am around agree that polverone refers to a slow,unmilled BP used as filler.

[TYRONEEZEKIEL]

Old Italian and Malta builders also use the term "rough powder for screen granulated or polverone. The Italian shell builder I study under uses hot BP for his rough powder/polverone. In his case he doesn't care if the powder burns slow or hot he is looking to fill the gaps solidly.

[marks265]

Polverone is screen mixed BP, usually the standard 75/15/10 formula with dextrin. It is not milled and does not need to be made with a hot charcoal. The purpose of polverone is to make a flammable, non-compressible filler used in cylinder shells. It is used to pack the triangular shaped space in between stacked comets or insert and the shell casing. It is also sifted around stars to ensure they are solidly packed. In some cases it is used when a very soft break is desired.

+1

[Wiley]

Polverone is screen mixed BP, usually the standard 75/15/10 formula with dextrin. It is not milled and does not need to be made with a hot charcoal. The purpose of polverone is to make a flammable, non-compressible filler used in cylinder shells. It is used to pack the triangular shaped space in between stacked comets or insert and the shell casing. It is also sifted around stars to ensure they are solidly packed. In some cases it is used when a very soft break is desired.

This is how I define it as well, along with (I think) pretty much anyone who builds shells according to Fulcanelli. However, because I have granular nitrate and meat-ground charcoal, I mill mine for a short period; long enough to bust up the chunks and mix everything thoroughly. It still burns really slow, and I use it as a filler.

[Peret]

The only time I tried using screen mixed powder for lift, the shell went about six feet in the air and fell fizzing at my feet. Fortunately it was a little one. I don't take any chances with lift and would never dream of using anything that wasn't milled, though I don't go so far as to press it to high density.

[benrenyi4]

KNO3（70），S（10），C(20)Or KNO3（69），S（7），C（24）2 g-dextrins boiling granulation，Best BP

[nater]

Peret, have you ever tried slower powder in a maroon with a sabot for lift like the Maltese? I have not, I never wanted to risk it and have fast enough powder available.

[Wiley]

Peret, have you ever tried slower powder in a maroon with a sabot for lift like the Maltese? I have not, I never wanted to risk it and have fast enough powder available.

I have! I did it with screen-mixed powder and shot some consumer-sized multibreaks. Now that I make good BP, the maroons are more trouble than they're worth, but it does work. There are pics and more details here: http://www.amateurpyro.com/forums/topic/9385-cylinder-shell-lift-and-break/page-2

 

The NC granulation was gimmicky and produced lousy soft grains, so dex is your friend here. The reason I used what I did is because I simply didn't have real dextrin at the time. If someone else does try this out, I'd be interested to see what their results were.

[Peret]

After my near death experience I haven't done any more experiments with slow powder. I suppose it might work with a larger amount, or with containment, but my milled powder's pretty good so I'm not motivated. I granulate my powder through 10 mesh onto a 15 mesh and re-granulate the fines so it's all very consistent. Incidentally I don't use any binder, just water, and my grains come out pretty hard, not soft and crumbly.

 

Last year at Do It I ran out of my own powder and used commercial 2FA under a couple of 4 inch shells. They both tossed and burst on the ground, which I assume is because the large grain 2FA was only half burned when the shell left the mortar.

[nater]

I routinely use commercial Goex 2FA when I can get it cheap enough with no issues for lift. 10% of the shell weight works fine. Was the mortar oversized?

[Peret]

That is a possibility. I didn't load them myself, they were in the showcase. 10% is what I used.