Whats the proper way of granulating BP?

[psyco_1322]

You really don't need a press to corn the powder. Just run the wet ball through a screen. Bear in mind that the Dextrin will reduce the burn speed of the powder slightly, especially at a 5% ratio. If your BP is made with fast charcoal, this may not be a factor for muzzleloading. The dextrin would certainly make your granules hard enough to withstand being jostled about in a powder horn or possibles bag.

 

Bob,

I think you are out of whack on your terminology. Corning is the process of pressing the bp into pucks and breaking it apart after it's dried. Granulating/Ricing, refers to wetting the powder, balling it up and pushing it through a screen. Granulating surely uses dextrin, or else you would have bp that would turn back to dust with minimal handling. Corning doesn't particularly need dextrin, but most people still use a bit in the pucks. He is also looking to make powder for muzzleloading, which does not use powder in an Fa grade, usually 2-3Fg is used.

 

As Mumbles said, you will always get some fines, it's just part of the process. You can always work them into the next batch. If your wetted powder is too dry, it can crumble through the screen and make a bunch of fines, but it's pretty easy to tell, ast there will not be much that remains the size you would normal get through that screen. Too wet and it all sticks back together, or forms worms. Another note to add is to try to push it through the screen, not drag the ball across in a grating action. This helps to get more solid granules and not little slivers and fines.

[Bobosan]

hmmmm...psyco, I do have worse days for sure. The terminology seems variable depending on where you read, including APC. So, I have probably mismatched processes. Corning to me is the act of breaking down the "pressed" puck or large "grated" granules. Granulation to me is the process of pushing the wet BP ball through a screen. Either method could contain dextrin. Please advise if my thought process is wrong.

 

"Commercial Meal-D is the extremely fine powder which remains after the granulation process, called "corning," which is used in the commercial production of granulated black powder."

 

http://www.skylighter.com/fireworks/how-to-make/Black-Powder-Quick-and-Cheap.asp

 

"#4: The size of the granules, especially with BP that is made into pucks that are broken up (corned)."

 

http://www.skylighter.com/fireworks/how-to-make/high-powered-black-powder.asp

 

"The thoroughly dried pucks or pellets are corned using a variety of techniques."

 

http://www.creagan.net/fireworks/blackpowder.html

 

Would you want dextrin in granulated BP used for rockets? Especially hand rammed?

 

I would think for BP muzzleloading, dextrin in granulated BP would be an asset as the granules would not break down easily.

[Poindexter]

While not a muzzleloader I do have a few cartridge arms around in calibers originally designed for BP.

 

What I have found is commercial BP really does run about 1.7grams/ cc, exception Hodgdon 777 runs about 70% of that, or 1.2grams/cc.

 

Mill dust fresh out of my ball mill runs about 0.3 grams/ cc.

 

I built a comet pump by taking my micrometer with me to Lowes-Depot and wandering around for a while. With a hammer, a pounding post and the pump I can run my dampened mill dust up to about 1.3 grams /cc.

 

Next up on my gear list is a shop press, i am thinking I will start with some calibrated marks on my pump plunger.

 

I find that relatively thin pucks dry faster, say diameter = 3 or 4 times height.

 

I am finding the small amount of clay in my 90% pure sulfur is a bit of a binder, but my grains are harder with a bit of dextrin, I am using +5% by weight when I use dextrin.

 

I started to see encouraging chronograph results when I weighed a known good charge of commercial BP and then started compacting the same weight of my powder into cartridges...its a pain in the neck, I really need to run my density up.

[goldwingnut54]

I don't have a chronograph. But I am learning that my dampened with water and "riced" BP (either white pine or eastern red cedar chip charcoal) is just as fast...if not faster than Wano or Goex...when lit in a long trough.

 

<<<<<<BY WEIGHT>>>>>> it makes a fine propellant in a muzzle loader.

 

It would NOT work in a cartridge at all. I would hope just not to get a squib load, not to be confused with a pyro squib. So in a BPCR (Black Powder Cartridge Rifle) my mix would be a non-starter. Or in a cap and ball revolver, with limited cylinder capacity. (Can you say "WHOOF"??!! At least it would make smoke )

 

OH.... BUT ROCKETS! I could like me some rockets....

 

So Poindexter, I'll be waaay interested to see what you learn.

 

On the issue of "fines", I was told by my flintlock addicted friends to never ever ever turn loose of my fines. As long as they aren't so fine they will blow out from under the frizzen when closed, they want my fines, thank you.

 

Looks like some screens are in order from McMaster-Carr. There are some mighty good posts on this forum regarding which screens to use for grading BP. I think I can read between the lines for my muzzleloading purposes.

 

On the terminology issue regarding "corning" "ricing" "granulating" and say... "green meal"....those kinds of terminology problems don't exist JUST in pyro alone. It's everywhere. We like to be brief when posting, but brevity and clarity don't always co-exist together in the same sentence. I knew EXACTLY what Bobosan was getting at. Full, complete sentences...along with some rudimental proofreading and punctuation make me happy every time. Maybe it is the nature of pyro that encourages this community to be cautious and clear, but I like it.

 

I got my introduction to BP from Dan Williams vaunted pyro pages, so my own personal terminology has evolved from that. If you haven't seen his stuff, here is link:

http://www.brianredm...lliams/top.html Talk about clarity!!!!! I'm so glad brianredmond.net (whoever that is) sees fit to continue hosting this fine information. I don't know the whereabouts of Dan Williams, but I hope he is well.

 

@ Psyco_1322, do you actually have your "ball" of BP so damp you can actually "PUSH" it through your screening device? If so, I am waaaaay drier than you and probably drier than I should be. That might explain why I have so many fines.

Edited May 13, 2013 by goldwingnut54

[pyrodundee]

just a quick tip poindexter - if you want to get to 1.7g/cc density without getting a press all you need is a big G clamp. Instead of pounding on your comet pump, calculate the volume of your pump when pressed to a marked line and weigh out the corresponding weight of dry meal/dex . Damp your mix (minimally) and load your pump on a flat benchtop and hook up your G clamp screwside down. You may need a hollow tube as an extension to get some more leverage but just screw it down until your pump marks line up, leave it a bit to settle and presto - pucks that will be as close to 1.7g/cc (when dried) as you need.

[goldwingnut54]

Pyrodundee, I've heard of a heavy bench vise...but G clamps (we call 'em "C" clamps, but I'm not sure why) is a new one one me. How do you measured your density?

 

Stan

[Mumbles]

Poindexter, your density values mirror mine for ramming. I was actually able to get close to 1.3g/cc by just using body pressure on a 1" diameter press. I also saw an increase in performance up to 1.7g/cc, but the tests were really not very scientific and should be repeated before any conclusions are drawn.

 

As far as the clamp goes, I've never been able to get a great deal of compression out of them. It will all depend on the size of your puck die of course. A clamp might work for something smaller, but probably wont have the compression needed for something larger made for decent production. I've seen a bench vice work for a die up to 4" in diameter. He had to crank, and let the comp settle, and then repeat a couple of times to get to the compression he wanted though.

[pyrodundee]

Measure the area of the "pump" ID then times it by the desired thickness of the finished puck. This gives the volume of the puck in cc's, which gets marked on the pump. You then measure out 1.7 times that cc figure of DRY meal/dex (in grams). Moisten, press and dry. Foolproof . For your own ease I recommend choosing the depth of the puck to give you a nice rounded weight of meal for each batch.

[Oinikis]

i think screen method is most accucurate and easy, however, if you do not have screen , you can do what i do. wet BP with a tiny amunt of water, s it's hard clay consistensy, and then crush it with my fingers. work realiable for me, but i am dreaming about big metal wire screen

[psyco_1322]

When granulating your powder, the powder should be just wet enough to be formed into a solid chunk, or ball. It should also be able to "snap" back apart, into two halfs. It does not push through the screen easy, not as if it were very wet. I mean pushing through as more of an action than an effort. Dragging the ball across the screen like you where grating cheese will give you little, thin slivers, like grated cheese. The resulting granulated powder can tell you a lot. If the pieces kind of ball up and stick together while try to spread them around, it's too wet. If you don't get a whole lot of granulates that are roughly the size of your screen, and it seems like a bunch of crumbles, you are probably just a tad too dry. It takes some practice to find the sweet spot, just remember to add the water slowly when you are about there.

 

I'm not sure you can tell very well from this picture. As you see, it's wet enough to stick together and be formed a bit, but still dry enough that it cracks apart if you try to manipulate it too much.

http://www.amateurpyro.com/forums/gallery/image/2131-black-angus-patties/

[Bobosan]

The first pic below is powder grated across a 4 mesh screen then corned and screened for size. Second pic is granulated through a 17 mesh kitchen screen with no dextrin added.

 

The larger mesh granules may look ugly but they still launch a baseball a good 275-300 feet.

 

I guess it really doesn't matter how you do it or what you call the process, as long as you get the desired results with minimal fines or waste.

 

Edited May 13, 2013 by Bobosan

[Poindexter]

I am still fooling with whether or not I need to go through ricing before I make a puck.

 

It doesn't seem logical that I should have to do both, but the chronograph will tell no lies.

 

I kinda want to stay away from weighing one pump load of mill dust, wetting it pumping it, weighing another pump load.... seems like a time vampire.

 

Haven't yet figured out how to for instance wet 500 grams of mill dust all at once and then pump it into 25 gram pucks. One way would be to use a measured amount of liquid each time and then measure out individual pump loads at slightly more than 25 grams. Another (more expensive option) would be to mount a pressure gage to the press and press simiiar sized lumps to the same pressure each time. Still thinking.

 

I should have enough chrono data to tell if ricing on the way to pumping is a wasted step on my next trip to the test lab, hopefully Wednesday evening.

[Mumbles]

One of the ways people get around this is by pumping many disks at once. Wet your 500g batch all at once with say 25g water (5%). If you want to do 25g dry pucks, the wet pucks will need to be 26.25g. When doing bulk preparations of BP pucks, it's easiest to pumps several at once. Weigh out your BP amount into a dixie cup or something. You really don't need to be totally exact, so lets say somewhere between 26.0 and 26.5g. This is easy enough to do relatively rapidly. It might seem like a variation, but +/- 0.25g is only 2%, and your final density will come out somewhere between 1.66 and 1.73, which is probably good enough. Add your BP load to the press, lightly hand compress it into a disk and drop a thin spacer on top of it. A circle cut from an aluminum beverage can is popular for these spacer, as are slightly thicker ones cut from a piece of bar stock the ID of your tooling. After you drop in the spacer, repeat. Doing this, you can build up several disks at once, and do the real pressing one time. Each cycle with the real press will generate maybe 5 or 6 disks total.

 

The other option of course is to get larger tooling. Many people choose to use large comet tooling for a double purpose, but purpose built ones are easy too. http://www.brianredmond.net/dwilliams/powderdie/powderdie.html

[goldwingnut54]

Psyco_1322,

 

Your Angus Patties picture touched off my giggle reflex! Grilling them to perfection will be an elusive goal though, I fear.

 

But these clearly have a bit more moisture than I am getting and I wonder if you are anywhere close enough to losing some "oomph". I've read where too much moisture can foul up the BP, and I've read that it isn't true. How long do these "ripen" before you granulate them?

 

Stan

[psyco_1322]

Psyco_1322,

 

Your Angus Patties picture touched off my giggle reflex! Grilling them to perfection will be an elusive goal though, I fear.

 

But these clearly have a bit more moisture than I am getting and I wonder if you are anywhere close enough to losing some "oomph". I've read where too much moisture can foul up the BP, and I've read that it isn't true. How long do these "ripen" before you granulate them?

 

Stan

 

While wetting and drying with water is going to likely reform crystals that are larger than what was in the mill dust, it's something that is hard to avoid. There are practices of using non-aqueous binders to avoid the re-crystallization of the nitrate, allowing a slightly faster burn. All of this is minimal to the difference between a good fast burning charcoal and something slow and crappy.

 

That particular picture was a 2 kilo batch of polverone, it's hand mixed bp, not milled, and actually has a slightly different ratio. It's filler for cylinder shells and my goal with the patties was to get pieces that were more larger than the little slivers I would have received from a grating action. I wanted something big and bulky to fill large, empty space in 6" cylinders. There is no period of time they set for, I had just processed the entire batch into patties, thought it was funny looking and grabbed the camera before I smashed them through the screen.

Edited May 14, 2013 by psyco_1322

[WSM]

My question is whats the proper way of granulating BP? And any beginner tips are welcomed. By reading through the posts I have a general idea of the process. Thanks ahead of time

 

The short answer is, whichever way you choose which gives consistently good results. The tough part is working out the kinks in your system. Asking here is a good start. Now you have to sort through the answers and choose for yourself which ones work best for you.

 

Good Luck.

 

WSM

[Poindexter]

Well I got a press. FWIW my 75:15:6 mix crosses the chronograph at about 85% of velocity achievable in 1873.

 

So homemade pump idea that seems to be working for me, I'll get back to you in a couple weeks when i get the chronograph out again...

 

First, find a close fitting cylinder and piston by wandering around Lowe's-Depot with a micrometer. As a rough SWAG I cut my cylinder about 8 inches long and my piston about 12 inches long - after I had my new press set up on the shop floor and could see what I had to work with.

 

Next bottom the piston in the cylinder on a flat surface like a workbench top. Apply a pencil or other suitable marker, mark a zero line all the way around the piston. Next flip it over, draw the piston back a little bit, eyeball the puck/comet/star size you want and scribe a second line on the piston.

 

Now measure the piston diameter and the distance between the two lines. On mine tonight my piston is 32mm in diameter and my two lines are 11mm apart, so 16 squared times pi times 11, my finished puck volume is 8.844 cubic centimeters, and my target density is 1.7 grams per cc, so I need 14.96 (do I hear 15) grams of dry powder in each damp puck.

 

So I measured out 45 grams of mill dust, diapered it until I was happy with the clumpiness, weighed it again and found 50 grams total. Fairly easy to divide 50 into three parts, 16.7grams of wet comp goes into the pump each time, press it to the line, bada boom bada bing, done.

 

Now I wait for it to dry...

Edited May 17, 2013 by Poindexter

[goldwingnut54]

I wonder what mesh/grain size they used to feed this?

 

http://youtu.be/XQdf_J9MgxI

 

If you haven't seen this, spend about 4 minutes and watch it.

 

Stan

Edited May 17, 2013 by goldwingnut54

[TheExplosionist]

I remember commercial BP reached 1.8g/cc density and has some kind of graphite coating.

 

How on earth would you coat BP grains with graphite? Gently tumble them with graphite powder somehow?

[dan999ification]

Exactly that, no need to be gentle either. At that density it won't crumble under its own weight.

 

Dan.