Whats the proper way of granulating BP?

[roketman21]

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

[Zumber]

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

wetting the composition and then pressing through desired mesh screen is the one method for beginner.

Another way is, wet the composition press it using comet pump then dry it for 2 or more days then granulate it using ceramic mortor and pestle .

be aware of second method and follow safety precautions.

[dagabu]

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

 

Lots of ways to skin this cat:

 

My new favorite is to make a 10% liquor of dextrin to water and use it to whet the milled BP with so that there is a 1% dextrin in the mill dust. I make a ball about the size of a tennis ball and push the ball through 1/4 mesh screen for lift and break for cylinder shells and 20 mesh screen for rocket fuel. The grains are very hard and do not crush when pinching them but are easily compacted for rocket fuel. The 1% dex seems to have no effect of the burn rate as it has some fuel value.

 

Traditionally, boiling water added to green meal makes pulverone and that is great for canister shell filler but with just ball milling the meal and then adding the boiling water, the pulverone is actually really hot and can be used for rockets, break or lift. The real problem is with the softness of the grains and the 1% dextrin seems to harden up the grains nicely.

 

-dag

[roketman21]

Thanks for both of your guys answers still trying to decide which method is best for me.

[Nessalco]

If you go the route of pucking and corning powder, it is much easier to break up the pucks right after they come out of the press, before they fully dry. I then grade the powder, and return any corning dust to the process. I use a plastic bag, wooden mallet, and thick aluminum plate to convince the pucks to 'take a break'. Takes about 15 minutes to corn and grade half a kilo of powder.

 

Though extra work, the grains are rock solid, durable, and you can get a consistency that will allow measuring by volume rather than weight.

 

Kevin

[dagabu]

Though extra work, the grains are rock solid, durable, and you can get a consistency that will allow measuring by volume rather than weight.

Kevin

 

Ditto with the 1% dextrin liquor method, the grains are also sized by mesh size and stand up to both lift and break requirements. Corning is known as the most dangerous aspect of making BP, I have never found it to be worth the time and effort.

 

-dag

[Potassiumchlorate]

Like I already pointed out in another thread, there have been tests done that show that BP for lifting display shells is better granulated without pressing. I'll try that method the next time.

 

Until now I have always too made pucks, chrushed them etc, but what's the point, when it won't perform any better? I also noted that Triple Seven seems to be granulated without pressing too.

[Potassiumchlorate]

I milled 1kg of meal D back to airfloat size. It took one hour. Then I added a slurry of 10 grams of SGRS in 125ml water, first by simply mixing with a spoon and then ricing through a kitchen strainer. I let it settle until tomorrow. Small, moist lumps burn increidbly fast. It seems like it really did it to re-mill meal D that was over from crushed pucks. Edited July 16, 2012 by Potassiumchlorate

[Potassiumchlorate]

Update: it was fairly easy to granulate it. About 50% passes through a 10 mesh sieve but stays in a 40 mesh sieve. 25% passes the 40 mesh sieve too and 25% stays on the 10 mesh sieve.

 

Weird thing is that the BP that stayed on the 10 mesh sieve seems to burn faster than the finer.

Edited July 17, 2012 by Potassiumchlorate

[Mumbles]

If you're getting that much fine material, you may want to reevaluate your process. If you do it right, less than 5-10% is quite achievable.

[Potassiumchlorate]

Yes, I think I should let those "balls" dry a bit longer before granulating them. I also think I took a little bit too much water, but too little and the SGRS doesn't activate properly. I used a grater of the kind you grate carrots and potatoes on.

[Mach25]

I am a beginner and I have used red gum and alcohol method which I find works very well. I double ball mill for safety then add 1% red gum/ alcohol solution strained into the meal until I get a nice ball. Then granulated as described in the above threads.

[Potassiumchlorate]

Red gum is good. They used to use Arab gum in the past, some are still using it.

 

The advantage with water is that the potassium nitrate is soaked into the pores of the charcoal.

 

I think that my smaller grains are faster than the big ones, btw. They just weren't dry enough yesterday. Up to and including 6" I think these small ones will be the best anyway.

Edited July 18, 2012 by Potassiumchlorate

[taiwanluthiers]

I don't even know where to get red gum other than pyro suppliers. Can find any other gum (gum arabic, guar gum, xanthan gum, etc.) but NOT red gum. It seems it's one of those things, like Parlon is very pyro specific. Dextrin is fine and is easily available (or made), I personally use shellac as a resin fuel because I have them...

[Mumbles]

Parlon is not at all pyro specific. We're not even a blip on their radar. Red gum is also used in the wood finishing industry.

[Potassiumchlorate]

taiwanluthiers - google accroides resin, accaroid resin etc.

 

You can also google pergut, which is another word for parlon.

[MrW]

I usually make pucks of BP (with some Dex) and then use a small grade cheese grater. This produces an array of sizes from 20 mesh up 100 mesh (usually 60+, I recycle into the next batch). Then i have my assorted sizes for their requirements. My 2cents worth.

[Swede]

I've played with all sorts of differing methods.

 

I have to agree, compressing and corning produces BP closest possible to commercial BP... I've even done the tumbling/polishing with a dash of graphite which turns the greyish powder into "real" black powder. Super dense, super hard grains, When the same MASS of corned BP is put in a container next to riced (screened), the pressed BP is about 1/2 the volume. It is a total PITA unless you have a corning device, and yes it is dangerous, but I've always corned moist. Overall very labor intensive.

 

Simply creating balls of BP with water + SGRS or Dextrin, or a little alcohol + red gum, then screening, probably fulfills 95% of what any pyro would want to do with BP.

 

Some pressed/corned BP:

 

 

http://www.5bears.com/firew/bpp09.jpg

 

Here's a disk of BP pressed with a comet pump. It is as hard as a rock. These are what get broken up into granules:

 

http://www.5bears.com/firew/corn101.jpg

 

Vs, some fine riced BP:

 

http://www.5bears.com/firew/bp027.jpg

[Potassiumchlorate]

On second thought even 1% SGRS seems to slow the powder down. I have 6mm ID 25mm long plastic spolettes. When I ram granulated BP that I used +1% SGRS in, the burn time is 4 seconds. Today I tried with exactly the same BP but meal instead. It burned for 3.5 seconds. Shouldn't compressed, corned BP without SGRS perform the same way?

 

Another disadvantage with BP that isn't pressed is that you sometimes need bigger liftcups, I also found out today.

[goldwingnut54]

(I know this is a dormant thread, but I'm not too keen on starting a similar one, when I can just bump an old one.)

 

I am getting too many "fines" with my method. I am currently misting water from a squirt bottle onto my 4 to 5 ounce piles of freshly mealed BP and cutting in the moisture with a credit card or Bondo spreader. I then squeeze the damp meal into a golf ball sized doughball and work it through 16 mesh aluminum window screen and allow the grains to dry on newsprint. (75-15-10 plus 5% homemade dextrin from corn starch. Aromatic Red Cedar, 99.8% prilled KNO3 and Sulphur from FirefoxFX milled 6 hours +1 for Dextrin.)

 

When dried, I'm going to have to re-grade the grains and *some* of it will be sub FFFF (Goex) sized. And I don't like it.

 

Am I doing something wrong, or is that just the way it is with my method?

 

Besides rockets, I have an interest in Muzzleloading, and consistency is going to be an issue to overcome. Fine powder is worthless for Muzzleloading.

 

Stan

[BlastFromThePast]

Are you using this for lift? You may have bad dextrin or you might not be using enough water. 5% dextrin is a lot for BP. I get pretty hard granules using only 1.5% and others use even less. Make sure your dex is the optimal color and try using more water. You didn't mention if you're wetting using just water or a water/alc mix?

[Bobosan]

Hi Stan,

 

Are you trying to granulate or corn the BP?

 

Granulating generally does not include Dextrin. Without a binder, the granules that are formed to stay pliable while keeping a more solid form for things like pressing rockets or BP firearms. Less messy to work with. A 10-20 mesh screen would be the norm for granulating.

 

Corning would use a binder, in this case the Dextrin. It should produce very hard granules. I use 1 to 1.5% Dextrin, add water and hand knead the mixture until a glistening ball of BP with the consistency of Playdough is achieved. I then let it sit for 10-15 minutes, knead it again and then push and rub it through a 4 mesh screen into a plastic tray. The tray is left in the sun to dry usually 2-3 hours depending on the moisture content of the BP ball. I recommend plastic or wax paper to keep the KNO3 from leeching off into the paper. The dried BP is then passed through the 4 mesh screen again to break up any larger dried chunks and then same thing through a 8 mesh screen. Then it is passed through a 10 mesh screen and anything not passing through is stored and labeled as 2FA. The BP that passes through the 10 mesh is put through a 20 mesh and anything not passing through is stored and labeled as 4FA.

 

You're going to end up with some fines from either process. You can save those for priming other things like stars or fuse or just reincorporate them into the next batch.

Edited May 11, 2013 by Bobosan

[goldwingnut54]

My primary goal here, is to step up my BP game for muzzleloading. Secondary goal is better rockets, but not right now. I am not currently producing mortar shells, but may after a time.

 

I don't have a press-so corning of pressed pucks would require me to borrow time at my neighbor's...very inconvenient. I wilk need to contunue wet granulation (riced--if I have the terminology correct) and yes, I'm using atraight water misted from a spray bottle. No alcohol.

 

Bob....I think by your explanation- I may need more moisture in the ball before granulating. At least that's what I'm thinking.

 

THANKS!

Stan

 

Edit: my dextrin is definitely suspect. I forgot to mention that. I will make more this weekend. I made my last batch on a hotplate, but it looked like the pictures I've seen. Slimy on the tongue...slightly sweet, and sticky. It was about as dark as a manilla folder-but lighter than a large mailing envelope.

Edited May 11, 2013 by goldwingnut54

[Bobosan]

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.

 

I let the BP ball sit for 10-15 minutes to give the dextrin time to completely dissolve before corning.

 

Physical description of your dextrin sounds about right in color. Never tasted mine. Try the oven at about 200 degrees for 3-4 hours on a cookie sheet. Rake through the mixture with a wide tanged fork every so often to cook thoroughly.

Edited May 11, 2013 by Bobosan

[Mumbles]

Your dextrin sounds about right. Another test I do is to smear a slurry of the dextrin and water between my fingers, and try to pull them apart. The better dextrins will give strings. Back before I found the wonders of commercial dextrin, I generally used my oven. I'm not sure what modifications would be needed for using a hot plate.

 

Anyway, fines are just something that you have to live with. They'll always be there. You can always reprocess them with the next batch, so it's not like they're lost material forever.