Pulverone (the type of BP)

[Smokelvr]

I may be confused, my impression was Polverone or Pulverone is a less dense BP made by wet mixing your BP into a loaf with hot water (because KNO3 is endothermic) to intimately mix and bind the BP, then ran through screens to create granules, which results in a 'luffy' relatively fast burning powder of intermediate power.

 

But, some call for ball milling the 3 mix first, then wetting and screening for pulverone

(don't see the reason, wouldn't the idea of breaking the KNO3 particle size be defeated when it recrystallizes out of the wet mix?

others offer it as the 'wet' method of making BP, avoiding the dangers of milling, with better results than green mix

 

I would think the best results would be achieved by ball milling the wet mix method, as you would 'load' the charcoal, which is a known absorbent, then milling the BP as fine as it can go, then making your final product, pressed and granulated BP

 

Am I confused, or just over thinking this?

[MikeL]

I may be confused, my impression was Polverone or Pulverone is a less dense BP made by wet mixing your BP into a loaf with hot water (because KNO3 is endothermic) to intimately mix and bind the BP, then ran through screens to create granules, which results in a 'luffy' relatively fast burning powder of intermediate power.

 

But, some call for ball milling the 3 mix first, then wetting and screening for pulverone

(don't see the reason, wouldn't the idea of breaking the KNO3 particle size be defeated when it recrystallizes out of the wet mix?

others offer it as the 'wet' method of making BP, avoiding the dangers of milling, with better results than green mix

 

I would think the best results would be achieved by ball milling the wet mix method, as you would 'load' the charcoal, which is a known absorbent, then milling the BP as fine as it can go, then making your final product, pressed and granulated BP

 

Am I confused, or just over thinking this?

 

Someone that actually knows what they are talking about will chime in... but for now I "think" that ball milling the 3 components together, thereby breaking the components into very fine particles, ensures that they are mixed very well. Think of it like this- If I have the right sized box of airfloat charcoal, the right sized box of KNO3, and the right sized box of sulfur, all solid, I'd have the right "mixture" of components for BP but it wouldn't light very well. Break each box up into 100 pieces and mix. Better but not a lot better. Break them up 1000 times, still better. The smaller the particle the better the mix. The more uniform the mix. So you mix it up fine, wet it to get it to a consistency for corning, then let that dry and screen it to get the various kinds of BP... 2FF, 3FFF, 4FFFF... whatever

 

We'll see if I know what I'm talking about in about 2 hours

 

https://vimeo.com/493118936

[Smokelvr]

Ah, sorry, if it's confusing, but you need to mill everything, well, not the KN, as long as you can dissolve it. The charcoal and S still need to be finely milled

your mixing is done in solution. Different method, the particle size of the KN would just affect how fast it dissolves, the KN size would then be controlled by technique in bringing the mix out of solution, controlling the crystal size.

 

UNLESS... the mix never enters a complete solution (all the KN dissolved) then it's particle size matters because you're making a putty where it's just wet and not in a solution state.

This is what I recall from my college chemistry, I forget the reaction, but the professor in my Chem 101 lab had us do a reaction where improper technique/process resulted in an incomplete reaction because reagents failed to come into solution, and adding more solvent to try to 'fix' the problem, added a different error unless you recalculated and adjusted for your solution ratios...

Edited December 20, 2020 by Smokelvr

[Carbon796]

Polverone, screen mixed, ruff powder as used in cylinder shells. Green mix is not a real fireworking term per say. Like wise, polverone is not "really" considered to be BP or a type of BP. Potassium nitrate should be ballmilled if you buy it in crystalline or prilled form. Commercial airfloat charcoal, sulfur, and dex, used as recieved. Once screened, it is incorporated with hot boiling water. There is not enough water added to make a loaf. There is not enough water added to dissolve all of the nitrate. It must be processed, if not purchased in a useable form.

 

BP, potassium nitrate, a hot charcoal( NOT commercial AF ), and sulfur. All three ingredients throughly ballmill together, plus a binder if your not pucking it, or using alcohol granulation. If you're using a binder, it is incorporated with cold water.

Edited December 20, 2020 by Carbon796

[MikeL]

The last time I made BP and tested it the result was pretty lame. The "last" time was also the first time i had ever attempted to make it. This was screen mixed:

 

 

This time it worked pretty well. This is not from the charcoal I made. It's commercial airfloat. All components were ball milled together for 4 hours

 

https://vimeo.com/493155445

 

Ball mill at work

 

https://vimeo.com/493118936

 

I'll try some of my pecan charcoal again before the year ends plus I want to granulate this batch and see how that works

[Bourbon]

 

This time it worked pretty well. This is not from the charcoal I made. It's commercial airfloat. All components were ball milled together for 4 hours

 

Starting to look good for commercial airfloat. Getting close to some respectable RP. Once you get that granulated, I bet you'll be quite a bit more impressed.

 

[Bourbon]

If you're using a binder, it is incorporated with cold water.

Why does the binder require cold water instead of hot? Iv never used a binder before. I haven't needed it. I suppose I should have, just to get my feelers in there.

[MikeL]

Starting to look good for commercial airfloat. Getting close to some respectable RP. Once you get that granulated, I bet you'll be quite a bit more impressed.

 

I feel like milling the components together was the primary reason this batch worked better. Milling it all separately increases the amount of time the components are "fiddled with".

[Carbon796]

It's more for the nitrate when making BP, than it is for the binder. You don't really want to dissolve the nitrate and recrystalize it. After having spent so much time, ballmilling the comp. Colder water dissolves less nitrate, meaning less of it has the chance to recrystalize into larger particles. Cold water, as in room temp or not heated, just to clarify.

[SharkWhisperer]

Why does the binder require cold water instead of hot? Iv never used a binder before. I haven't needed it. I suppose I should have, just to get my feelers in there.

Never noted a huge distinction in burn rate using hot versus cold water. Hot is faster, but not necessary, to activate dextrin--if you moisten at most usual workshop temps, and just leave it alone for 20 minutes or so before granulating, the dextrin will be sufficiently activated to give hard granules. I use only 30% water--70% isopropyl alcohol for 1.5-2% dextrin-bound BP and it works fine). Being endothermic when dissolving, your water/solution will decrease in temp as nitrate dissolves (like how ammonium nitrate cools when dissolving in disposable ice packs for first aid).Given nitrate's solubility curve vs temp (it's soluble but not hugely so), recrystalization during drying, real or imagined, has never been an issue. The solubility curve really isn't too steep going from 10C to 20C, which is the range most operate within. I tried to upload a solubility vs temp curve, but the image wouldn't upload--just look up "potassium nitrate solubility" and select images. 10 or 15% water is not going to dissolve all that much nitrate at typical user temps. And my water level is 30% of total liquid added (maybe 5% final? mostly alcohol for good dough formation, minimal nitrate dissolving, and rapid BP drying. Water alone, or with a little alcohol to break surface tension, works just fine, too. Cheap too, and used by most. I just like to have my powder dry quickly. That's why I use 91% IPA for granulating no-dextrin BP for anything besides lift/burst, and you still get the speed increase from making dough and granulating it (and it dries really quickly but I store it with desiccant bags overnight to remove the last bits of water if not in a dryer box). Still, try to standardize your procedure,whichever technique and materials you end up favoring. Quality control & repeatably reliable burn rate should be standardized to suit your needs.

 

MikeL--Your newest batch is most definitely improved, but it still burns rather slowly. Granulation will speed it up some, but I expect it will still be a bit slow burning overall. Don't toss it out, for sure--It's probably great for fountains/gerbs, slow-burning star primes, and making blackmatch. Maybe some slow-burning star comps. You could see if a few more hours of milling speeds up the burn rate, but you'll hit a point of diminishing returns. Not currently ideal for lift/burst, salutes, or rocket fuel. It might be time to move beyond the pecan charcoal, having given it several fair chances. Might just not be ideal--kinda reminds me of the generic hardwood airfloat that's available everywhere, though it's cheaper (and messier) to make similar from lump charcoal (I use cowboy brand, but wood and country of origin changes--pick out the lowest density chunks). If you want a small quantity of super hot willow or ERC charcoal to give you a clear idea what you're aiming for in speed, then just PM me and I'll mail a sample over for you to experiment with and compare. Kinda night/day... Once you get your chems & process down to your satisfaction, you'll be able to make reliable and consistent BP in your sleep essentially.

 

KNO₃ Solubility Curve: https://www.yenka.com/activities/Solubility_Curves/attachments/Solubility%20Curves%20-%20solubility%20curve.gif

Edited December 21, 2020 by SharkWhisperer

[Bourbon]

Thanks guys for the explanations.

 

I have always granulated using 70/30 Denatured/Distilled. Tried other ratios, but they were never quite right for me. I have also, never used hot water. I figured it would be useless with alcohol involved. I read in many areas and seen video of people using "almost" boiling water with alcohol to granulate (not the CIA method). I couldn't figure that out. Maybe I'm thinking the alcohol would evaporate before, or too quickly when put it to use.

 

Sorry for distracting from polverone/pulverone discussion. I'll ask a couple more questions elsewhere, after I have a look around.

[SharkWhisperer]

Thanks guys for the explanations.

 

I have always granulated using 70/30 Denatured/Distilled. Tried other ratios, but they were never quite right for me. I have also, never used hot water. I figured it would be useless with alcohol involved. I read in many areas and seen video of people using "almost" boiling water with alcohol to granulate (not the CIA method). I couldn't figure that out. Maybe I'm thinking the alcohol would evaporate before, or too quickly when put it to use.

 

Sorry for distracting from polverone/pulverone discussion. I'll ask a couple more questions elsewhere, after I have a look around.

Many consider using 70-91% IPA to granulate to be a waste of money. Though some add 10-25% alcohol to "reduce surface tension". Probably does, but never seen a real difference (never done a side-by-side) between using water-only, 20% alcohol in water, or store-bought IPA on end result. I like my powder dry fast, and you don't really use tons of solvent to granulate, so IPA it is. If I were out of IPA for some reason (unimaginable), then I'd have no issues using water from the tap, though that would be a first for me. Distilled? Dunno. Guess it depends on how much/what contaminants are in your local tap water. Only thing I use distilled water for is on the rare occasions when I make Mg-based star comps (not MgAl) where I want zero chance of water-associated ions/impurities in contact with a very reactive metal powder. Or other super-reactive comps. But if I lived in Flint, MI, then I'd probably avoid the tap water. And I'd probably avoid any sulfur-smelling well/pump water. Unlikely the water in my Walmart/CVS 70% or 91% IPA is distilled.

 

Acetone, too, is modestly hygroscopic and is going to contain variable amounts of water, either from synthesis/bottling or absorbing from the air. I make a lot of rubber stars etc, and have never given water in my acetone a second thought. Never had an issue. So, while I rarely bother with distilled water myself except in very specific circumstances, it's not so pricey at all, and if that's your thing then fantastic. Continue with what you prefer. That said, I highly doubt that many---well....any---Chicom factory uses distilled water for essentially anything at all.

Edited December 21, 2020 by SharkWhisperer

[justvisiting]

In China, I don't think they even use distilled water in the distilled water!

[MikeL]

I milled another small batch of BP with Pecan (the first batch) charcoal for 5 hours.

 

The video isn't the best but the results were better than the commercial air float.

 

https://vimeo.com/493540184

[SharkWhisperer]

That's a noticeable improvement and it will get even faster after you wet-granulate it! You could also try to mill it for another 2 hours and see if that speeds it up just a little more. I know with one of my little hobbyist mills (Harbor Freight) and lead balls, I usually go somewhere around 8 hours before I start to see diminishing returns with 200g comp in the barrel. Any clumping and it's a do-over with freshly dried chems. Bigger mills with more media will reduce necessary milling time.

 

I'd consider that burn rate a 7-7.5 out of 10 on my (very) subjective scale, which is definitely usable. Burn rate will go up to at least 8/10 after granulation, which ain't bad at all.

 

Your pecan charcoal has utility.

[MikeL]

I can easily mill another batch tomorrow as long as there's no rain. Once the mill is spinning I can do other things. I'll try for 7 or 8 hours. Hopefully I can wet granulate some tomorrow while the mill is spinning.

 

I was not expecting the reaction I got. I already had my mind made up that it was just going to be a repeat of the first time. Now I see why you've been saying - make your own charcoal. I need to make another batch of charcoal. Probably more than one. I won't see Pecan sheds the same way anymore

[SharkWhisperer]

I can easily mill another batch tomorrow as long as there's no rain. Once the mill is spinning I can do other things. I'll try for 7 or 8 hours. Hopefully I can wet granulate some tomorrow while the mill is spinning.

 

I was not expecting the reaction I got. I already had my mind made up that it was just going to be a repeat of the first time. Now I see why you've been saying - make your own charcoal. I need to make another batch of charcoal. Probably more than one. I won't see Pecan sheds the same way anymore

You could retain a few grams of this powder for comparison to your next batch. Or retain a few grams and just put the rest of this same batch back into the mill for a couple more hours, perhaps withdrawing a couple of grams each hour for burn comparisons. Then you'll have a better idea of optimal milling times with your chems/equipment and won't need to guess in the future (unless you change something). This way you can quickly determine the point of diminishing returns with milling time using your set-up. We use a lot of BP in all facets of pyro, so it's important to get past this initial hurdle, as you seem to be accomplishing quickly and thoughtfully!

 

Maybe also burn a small pile of a half-gram or gram on a plain piece of white writing paper and examine residue and char marks. Maybe take a photo of the post-burn paper. , There should be no holes burned through the paper whatsoever., and minimal residue. Quite possibly, this batch as-is will pass this test.

 

But ultimately you're going to want to wet-granulate your BP unless reserving it for a prime. This will both speed up your BP burn rate very noticeably, and also allow you to screen-separate it into different size ranges (different sized BP has different uses, but you know this well because you reload your own ammo).

Edited December 22, 2020 by SharkWhisperer

[Bourbon]

I milled another small batch of BP with Pecan (the first batch) charcoal for 5 hours.

 

The video isn't the best but the results were better than the commercial air float.

These are the times you start to feel really good about what you're doing. A bit excitement comes into play.

[MikeL]

That's true. Cautiously good and definitely pretty excited

I just weighed my "good charcoal" and I have 104g left. 104 / 0.15 = 693.33g divided by 454 = approximately 1.5lbs of BP. That seems like a lot compared to what I've been making but it's really not. The dilemma now is how to store "that much" BP (it kind of cracks me up to type that. I'm reload and 1.5 pounds ain't much). If I hold on to the charcoal I won't be able to mill it when I get to NM. There are too many houses next to me plus I rent there.

 

I'm always surprised by how much BP can come from adding some ground up rocks to a few burnt twigs

Edited December 22, 2020 by MikeL

[MikeL]

How important is weighing to the 1st or second decimal point?

 

Example. I weighed a container and got

2.0 oz. Converted that to grams = 56.699g. Switched the scaled to grams and it reads 56g. Being off by almost 0.7g hurts my head

Back calculating the BP I can get from 56.699g = 774.87g and 56g = 773.3g

 

774.87g x 0.75 = 581.1525g of KNO3

773.3g x 0.75 = 579.975g of KNO3

 

The difference for KNO3 is 1.57g. I just put two 50g weights that are used to calibrate my scale that I use for reloading and the scale is of by 0.1g high. To calibrate the scale I need a 5kg weight and I don't have one of those.

 

I guess the question is do I just forge ahead and use the grams (no decimal point) scale?

[BetICouldMake1]

I don't think you'll have issues unless you're mixing very small batches where that margin of error would represent a significant shift in ratios. Shifting things 0.5% isn't going to make a bit of difference. I use two scales for pyro, one accurate to the closest gram when weighting large batches for milling BP or mixing star comp, and a smaller scale accurate to .01g for weighing things like flash bags or break charge for crossettes.

[Bourbon]

I notice you say weights for calibration of a reloading scale, Mike. Are the weights for grains or grams? That will make a difference. If I misunderstood please disregard my question.

[MikeL]

I notice you say weights for calibration of a reloading scale, Mike. Are the weights for grains or grams? That will make a difference. If I misunderstood please disregard my question.

 

Good catch. In this case they are 50 gram weights. 770-ish grains.

[MikeL]

I don't think you'll have issues unless you're mixing very small batches where that margin of error would represent a significant shift in ratios. Shifting things 0.5% isn't going to make a bit of difference. I use two scales for pyro, one accurate to the closest gram when weighting large batches for milling BP or mixing star comp, and a smaller scale accurate to .01g for weighing things like flash bags or break charge for crossettes.

 

I have a .01g resolution scale around here somewhere. The bigger scale is 1g resolution. I need to get a 50g weight so I can calibrate it. I use it at sea level and 5,500'. According to the manual it should be calibrated when altitude changes significantly.

[BetICouldMake1]

A nickel weighs 5 grams. Could use a stack to check/calibrate