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My Lift Powder Isn't So Fast


wizard7611

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Hello. I've been noticing my lift powder has not been as fast as I wanted it to be. It is at about eight mesh, but still doesn't burn as fast. I have dried it out for two weeks now. The black powder has been put in the ball mill for two days.

 

Here is the formula I used:

 

75% Potassium Nitrate

15% Airfloat Charcoal

10% Sulfur

10% Dextrin

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First of all, you don't need that much dextrin. 3-5% is usually plenty.

 

Secondly, what sort of charcoal are you using? This material has the biggest variability on black powder speed and quality. Commercial airfloat is pretty mediocre in terms of speed. Some of the higher performing charcoals are Willow, Paulownia, Alder, Balsa, just to name a few. Eastern Red Cedar, which is available as pet bedding, has become increasingly popular over the past few years. Most of these are cooked at home. There are a few vendors for these types of things however.

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First of all, you don't need that much dextrin. 3-5% is usually plenty.

 

Secondly, what sort of charcoal are you using? This material has the biggest variability on black powder speed and quality. Commercial airfloat is pretty mediocre in terms of speed. Some of the higher performing charcoals are Willow, Paulownia, Alder, Balsa, just to name a few. Eastern Red Cedar, which is available as pet bedding, has become increasingly popular over the past few years. Most of these are cooked at home. There are a few vendors for these types of things however.

How can I re-granulate black powder that's already been granulated?

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To re-granulate mine I started by putting it back into the ball mill, and repeated the whole process

 

Also I would suggest adding some green meal to it in order to dilute % of dextrin.

 

DaM

Edited by DaMounty
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With dextrin less than 2% is risking soft grains 2.5 - 3.5% is fine according to your personal preference, OVER 4% dextrin starts to spoil the powder.

 

As you say 10% dextrin then IF you used a prime charcoal (for your location) then add some of your BP to three times it's weight of straight (no dextrin) BP ingredients and mill for long enough (by your mill's needs) that will get the mix to 2.5% dextrin, which should granulate well, and still be powerful. IF you used other than a prime charcoal start there with remedial work.

 

Find out what the prime charcoals are in your area, start with Mumbles' list above.

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The right charcoal is absolutely paramount. Like what these guys said. The very first batch of bp I made with paulownia set me straight. I'm lucky I have a couple big old pauls behind the house and until I found this place here I didn't even know what they were. So for starters as mentioned above look for the cedar pet bedding and try again with no more than 2-4% dextrin.
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If you really want to save yourself loads of trouble. Abandon that batch for lift. You do not need any dextrin for lift. Save what you have for making blackmatch or polverone. In fact. That stuff would be great for polverone. It would bind so hard that it would make a great filler even if it does burn quickly. It is not worth the effort to try to save that batch.

 

Make a new batch with no dextrin. Use eastern red cedar charcoal. This is extremely simple to make and you can buy bales of eastern red cedar pet bedding at a tractor supply.

 

Make sure your chems are dry before you mill them.. Then granulate your new batch with denatured alcohol through your screen. The denatured alcohol activates the residual oils and resins in the charcoal which act as the binder. You dont have to worry about adding a binder to get stiff grains.

 

As long as your mill is optimized your lift problem will vanish after following those steps..

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Rules for good BP!

Good charcoal

Dry chemicals

well milled.

 

Either puck and corn or granulate with dextrin 3% MAXIMUM.

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So I should no longer use Air Float charcoal?

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So I should no longer use Air Float charcoal?

Ditch the air float for lift and burst. I use willow charcoal, but others use red cedar. For lift I use the standard 75/15/10, I do not use any dextrin. I wet with isopropyl alcohol until I can form it into a dry ball, you don't want play-dough or putty, just wet enough to hold it together. I granulate through a 4 mesh screen. Has never failed me since I switched to this method.

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"Airfloat" is just a measure of the particle size, it's more important to get charcoal from the right wood or tree. Once you have charcoal from a good wood, you can mill it to airfloat yourself. It seems that some people sell "airfloat" charcoal without specifying what wood it comes from, that's the wrong way round. You need to chose the wood first, then charcoal it, then mill it to fine powder.

 

There are lists of "good" woods for pyro charcoal, but the wood needs to come from your locality. It's useless to say "I use willow" (which I do) If willow doesn't grow near you.

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An easy start would be to purchase some cedar pet bedding, from Wally Mart

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"Airfloat" is just a measure of the particle size, it's more important to get charcoal from the right wood or tree. Once you have charcoal from a good wood, you can mill it to airfloat yourself. It seems that some people sell "airfloat" charcoal without specifying what wood it comes from, that's the wrong way round. You need to chose the wood first, then charcoal it, then mill it to fine powder.

 

There are lists of "good" woods for pyro charcoal, but the wood needs to come from your locality. It's useless to say "I use willow" (which I do) If willow doesn't grow near you.

I don't know what kind of wood is in it. The description says a mixture of hard woods, but which woods?

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This ( hardwood charcoal) is usually the charcoal used for making stars and spark effects . It makes for slow BP, but can be used . Youll need much more for lift than a BP with more reactive charcoal. If your not afraid of getting dirty , you could make your own . THere are a few sites that sell willow charcoal ( air float ) and it will be your best bet for hot powder if you just want to buy charcoal.

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Willow and Alder are the local traditional woods for making prime BP. -It's what the Royal Gunpowder Mills used for hundreds of years. In other locales and climates then Pawlonia Balsa and Vine woods can be found easily and make good BP. If you talk to pyros local to you they should offer you advice about suitable fast charcoals and suitable places to source it.

 

99% of all BP problems involve attempts to make BP with unsuitable charcoal from unsuitable timber. Lumps of charcoal should NOT need tools to make them crumble, if they don't crumble by hand than they are too hard to make good BP.

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i am pretty new to making fireworks, i had many problems with my bp. first thing sure everything was dry. second i changed my charcoal to tropical red cedar. third was i bought a good drum for my ball mill and added a lot of lead balls to the drum was 1/2 full. milled all my charcoal for 4 hours. then added the kno3 and the sulfur all dry, milled for 4 hours and used no dextrin , granulated with denatured alcohol. it drys in a few hours and is fast enough for me. it solved a lot of peoblems for me.

 

memo

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Although the alcohol approach works and is really fast, it is expensive , and I have found that it results in soft grains of finished powder. I find that If I made a lacquer out of redgum and alcohol and mix it with the milled bp, it is better than adding alcohol to the mix with red gum in the milled powder.

For those of us who make 20-100# of powder a year, it is best to use dextrin for the cost and simplicity .

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BP RICE HULLS FOR EVERYTHING !!!!!

 

I just make ALL my bp base with 2 % dex. once you get your mill optimized and get the hot charcoal the binding method doesn't make a huge difference. The speed in which it's dried (might) it does for me.

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Lumps of charcoal should NOT need tools to make them crumble, if they don't crumble by hand than they are too hard to make good BP.

I cooked a 5 gallon retort of the 'pet bedding' red cedar and would like to share my results. The retort was a simple 5 gallon steel bucket with 5 1/4" vents, 4 around the perimeter on 90 degree angles, and one in the center. It was cooked over an open fire suspended on a steel grate, and was turned about every 15 minutes. After wood gas flames no longer flared from the vents I cooked another 45 minutes.

 

After the bucket vents were covered and the retort cooled I opened it and 'airfloat' dusted into the air. As far as I am concerned the term 'airfloat' just means any charcoal of any species of wood that will be airborne under certain conditions.

 

Then the process of seeing just what I made started. I took a handfull and put it in a 40 mesh screen and gently sifted and hand rubbed it through, most passed. What did not was probably undercooked or the "heartwood " of the cedar which is much more dense than the outside wood or sapwood that feeds the tree while it is growing, and is much more softer.

 

The difference is easy to see in the pet bedding chips, heartwood is red, sapwood is almost white.

 

The easily crushed and milled coal makes hot lift and burst for me, the others make decent sparks for charcoal stars, (pine is better as has been well documented).

 

The making of charcoal is almost an art and takes a lot of research and dirty fingers till you get it right.

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Search up "Softest Woods" on google and look through it until you recognize a wood that you think is at the nearest lumber store. For me it is cedar wood.

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  • 3 weeks later...

Hi all, new here but thought I'd share something and ask some follow-on questions about it.

 

I'd bought some "airfloat" charcoal (probably hardwood) from one of the pyro places before I knew anything about BP besides the basic formula. Mixed up a batch of 75/15/10 +1 dextrin in my new Harbor Freight rock tumbler with 1/2" ceramic media, milled for 3.5 hours, wet with water, made a lump, screened it through 4 mesh, let it dry two days, ran through the 4 again, then sorted it with 12 and 20 screens.

 

Made some little 1/2" and 3/4" mines with it, just shooting a star or two, and some flying fish fuse bundles, using 10% of the weight of each payload as a lift charge, using the -4+12 granules (equivalent to 2FA, yes?). The results were disappointing to say the least. Doubled and then tripled the powder charges, and it was only then that the effects got high enough to burn out before coming back down, but even then they weren't satisfying.

 

So today I did some more experimenting. I had some 1.125" ID tubes, 8.5" long, I'd salvaged from a commercial cake, so I hot-glued four of them to a base. Then I made four dummy shells from some 3/4" ID tubes, 1.75" long, filled with sugar and capped with rammed clay on each end. I wrapped them with some magazine paper and blue painter's tape till they barely fit in the tubes. They weren't jammed in, but mostly slid down under their own weight. Each weighed 27 to 28 grams.

 

Now mostly I've read that 2FA size grains are used for lift, so that's what I used yesterday. But today I was thinking that finer grains ought to give a bigger oomph for the same weight, so that's how I set up my four tubes. In the first I put -10+12, 30% of the weight of the shell, about 8 grams. In the next I used -12+16, in the next -16+20, and in the last, whatever passed my 20 screen. (These are stainless steel woven screen fabric from Grainger, so probably similar to what others use.) So guess what? The second shell went higher than the first, the third higher still, and the fourth went highest, probably to a height I'd feel comfortable with breaking stars at.

 

So my questions: this is probably really slow powder, right? I probably needed to mill it longer, and I haven't yet done the mod to make the HF mill drums turn at 80-90 RPM. That's okay, it was only a 200g batch, and I have some willow charcoal coming in the mail. But now that I've proved to myself that it works better in smaller grain sizes, is it okay for me to use it like that? More generically, if you made up a batch of BP and it was a little slow, is there any harm in using smaller particle sizes of it in order to "speed it up"? You probably wouldn't want to use -20 to dust like I did here, but could you use -16+20? Does it get into the "hardness/violence" of the lift charge damaging shells or something? Is it okay to use 4FA as lift?

 

Thanks in advance for any insights.

Mike

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Great experimenting and testing. You certainly can use a finer granulation for lift. Several chinese companies use this ploy to save on black powder. I use 4FA all the time shells 3" or under. It gives me better and more consistent results. As you mentioned, at a certain point I find 4FA to be too violent. I've lifted shells as large as 6" with it. I know a few people who use it or have used it in even larger shells as well. Sounds like you're on the right track.

 

Since your mill isn't yet optimized, you can always just run it longer. It took me 8-12hr in the same mill before modification.

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Mumbles is right on. I might add that you can use a window screen for granulation to achieve a smaller grain size right off the bat. For extremely small shell size, I don't feel like the so called violence of the lift charge comes into play as much.

 

The willow charcoal will speed things up in any event.

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