optimum triangle crackers

[Purple Fire]

i have recently been experimenting with triangle crackers as a small cheap bang to sell to inocent children who, as yet, are unfamilliar with the joys of HE's. i currently make mine with a 3cm strip of A4 computer paper folded 11 times and filled with 12:7:10 KMnO4:Al:S flash mixture. does anyone know what creates the biggest bang?

how much flash inside
how many folds thick
composition of flash
size of initial strip
etc.

also, how do these variables change to create the optimal bang for AP? (maybe for demonstrations to slightly more experienced friends etc.)

any info greatly accepted

[inferno]

IME...you dont need to "pop" the paper to get a bang. Put even 4 toy caps into a 1-1.5cm wide paper strip, fold over about 8 times, and youll get a tom thumb type of bang. Nothing loud, but its still a very cheap bang. (Toy caps - AU$2 for 160. 2/160=1.25 cents each. Thats 5c per cracker, or US 2.5c.) Fuse, i just use sparklers, paper well if you cant get that...

For a cheap and easy cracker, get a 1.5cm wide piece of paper, put some BP (its cheaper than flash) in and slip a fuse it, itll be VERY cheap, and if you sell them for 15-25c you wont make much, but if you sell 200=$50..

Use flash if its all you have but IME of the costs of fine metal powders its probably costing a lot more than a little BP would. These kids will be impressed by whatever you make, even if it makes a weak crack

[Purple Fire]

You'd be amazed at what it takes to impress some of the people I know :( My best friend also makes explosive devices and whatever I sell them has to better anything he has shown them!
Flash is actually cheaper than BP for me because I get the Al powder for free (400 mesh :) ) also KMnO4 is easier to get hold of than KNO3 even if it is slightly more expensive.
I'm specifically interested in triangle crackers because I am becoming very proficient in folding them quickly now and they require minimal taping and no glue. I also think they are dramatically underrated as far as fire crackers go and they are by far my favourite :) !

You dont need to pop the paper?!?!?!
I've always found that if the casing is too strong for the mixture inside to burst it, then you get a dissapointing whoosh/thud as opposed to the bang/crack you are after. likewise if the case is too thin the bang/crack is considerably less than what it could be.

<small>[ June 25, 2002, 05:01 AM: Message edited by: Purple Fire ]</small>

[Anthony]

Loudest bang:

Flash quantity: half fill, leaving expansion room
How many folds: As many as possible
Flash Comp: Fastest burning + highest gas volume yield (KMnO4 is pretty fast considering the ease of preperation)
Size of initial strip: As long and wide as practically possible (gives greater internal volume - fit more flash in).

The fastest burning comp in the heaviest confinement will give the loudest bang. Just screw around with the variables until you get something efficient.

[Zambosan]

I would think you'd need to wrap it pretty tightly... I wouldn't play around with these though.

<small>[ July 18, 2002, 01:02 AM: Message edited by: Zambosan ]</small>

[YTS]

I have used the paper from the front of blank cdr discs unfolded them & cut them into 3 equal strips about 40mm wide each & 250mm long use all 3 strips for 1 cracker i find it makes it easier if you make each strip slightly bigger as you progress i tried it first with kmno4 s & al with good effect then i tried it with kclo3+ sugar & i was suprised how well they worked i thought they were going to shoot off like a rocket but the kmno3 s & al were far better i dont think ap or hmtd would be as loud as kmno3 s & al but i dont know as i havent tried

[Polverone]

Agh, my bleeding eyes! Those mysterious punctuation characters (and the Shift key) can sometimes improve textual communication, you know.

Anyway, it may be different with HMTD, but with flash in triangle crackers I have found that the most important variable is confinement. Use heavy paper, like from grocery sacks or artists' tablets. If you aren't making impressive noises yet, you'll get a lot more improvement by doubling the paper thickness than by doubling the amount of flash. If you want to make your flash more potent you might want to remove any coating from the aluminum by *carefully* heating it in an oven or washing it with acetone.

It's good that you are getting good at making the triangles, because the paper should always be tightly and precisely wrapped to get maximum bang. I've found 2 inch wide, 3 foot long pieces of art paper (multiple strips taped together) to give good results even with relatively wimpy flash, so long as the triangles are well-constructed.

As far as HMTD/acetone peroxide go, they are more potent than flash but I don't like the noise as much. It is too high. I prefer "pow!" or "boom!" to "crack!"

<small>[ June 25, 2002, 05:32 PM: Message edited by: Polverone ]</small>

[Nika452]

I have found that if you use a mere 2" x 11" piece of printer paper, and wrap it with one layer of that packaging tape with fibers in it, you can get quite a decent bang with only black powder.

[Purple Fire]

Im not sure about this "the more confinement the better" thing especially with flash. As I said, I use about 11 folds and, if you up that to 22, the container rarely breaks and the bang is deeper, but much much quieter.
I have just found the perfect triangle cracker paper! I dont know if anyone here plays field hockey (probably not any Americans, Germans perhaps?) but there exists a stuff called "shaft guard". It's like a really thick sticky plastic strip that you wind round your hockey stick to stop it getting chipped. Anyway, the backing tape for this is a thick, plastic coated, very strong, stip of paper that's about 4cm wide by about 1.5 meters long. It is PERFECT! Shops that sell hockey sticks will usually offer to shaft guard a stick you buy from there, so i assume they will have oceans of the stuff to give away if you ask :)

This weekend I plan to do a proper controlled test with different numbers of folds, thinknesses, volumes etc. etc. I must say I am quite intrigued as to what the results will be! Though i dread to think what the neighbours will say, they are used to bangs, but not 50 in a weekend :D

[inferno]

Purple - i havent done much with triangular firecrackers, though i can see potention for sure, much easier than making cardboard tubes and endplugs! Ive done small tests with tiny amounts of armstrongs. The paper isnt shredded, it all comes out the fuse hole, but they make a reasonable crack.

And be careful with these kids, if they dont know how to make this stuff themselves, they mightnt know the dangers...they might keep HMTD crackers in pockets, or treat them roughly etc, if they get hurt you get sued

[krimmie]

I have seen that formula posted on rec.pyrotechnics. I tried it also and found it has way too much fuel to give a good boom(unless tightly confined).

KMNO4 12 parts
Al 7 parts
S 10 parts
*This equals 41% KMNO4, 24% Al and almost 35% S!

Sulfur acts as both an ignition promoter and FUEL...so this formula is approaching 60% fuel! Way too much. Change your fuel/oxidizer ratio.

Also, if you plan on distributing these, I would not add Sulfur. The report is just as loud without S and the product is safer. For my own use, I use the following formula; KMNO4 68%-Al 23%-S 9%, it is loud and powerful( but I don't give any of these out to friends/family). If I were you, I would use the classical 70% oxidizer 30% Al. Any percentage of oxidizer between 65%-70% and the rest Al works fine.

<small>[ June 26, 2002, 07:31 AM: Message edited by: krimmie ]</small>

[00Buckshot]

I used to make triangle salutes every day, they were my favorite for a long time. I have only tried black powder and HMTD but of course there was a world of difference between them. The BP is alot of fun because it is so much safer than HMTD, and it makes a nice amount of fire compared to HMTD which makes no fire at all, but a HMTD tiangle will rip open a tree.

Anyone ever try making a giant triangle? I made a BP triangle that had a starting strip of paper that was 30cm. It was about 1.5 meters long, and help "about" a half kilo of BP. It was fun, big fireball.

<small>[ June 26, 2002, 10:24 AM: Message edited by: 00Buckshot ]</small>

[Purple Fire]

Hhmmmmm, I was wondering about the success of the flash, I thought it was rather good, and INCREDIBLY easy to light, but I think I will have to try some 3:2:1 ratio to compare it with. I shall buy some more KMnO4 asap.

inferno: I was never intending to sell AP crackers to kids, Jesus Christ! I like my friends WITH hands!!! That was just an on-the-side for personal experimentation only.

I will try a highly confined one now and see if it any better than the ones I have been making. Could it be that the weakness of my flash means that it is not performing well under heavy confinement?

Ahhh well, new flash should soon fix that! :D

[vonK]

Purple Fire, do you mind letting me know where you are getting your KMnO4 and Al?
I have bought KMnO4 from pharamcies, but it's $6 for 25g. I also have to make my own Al powder.
Needless to say I haven't much experience with flash, but blackpowder is a piece of piss.
I buy my KNO3 from a local garden store as stump rotter at $8 for 500g. You could order some from the NZ Rocketry web site, they're based in Onehunga, I think they quoted me something like "3kg minimum order costing $32 including shipping and handeling".
I've had a couple of requests from guys at school wanting to buy skyrockets for Guy Fawkes, and blackpowder, although it gives a nice report, isn't that impressive as a payload, so if you could let me know where I could find some Al powder I'd be very grateful.

Thanks
Kurt.

[xtreme]

vonk:

$8 for 500 gram KNO3 is very expensive !!
I get 25 Kg (25000 gram) for almost the same price (13 Euro)

Try a farmershop (agrarical) for KNO3 and other fertilizers.
Other fertilizers (Ca(NO3)2, NH4NO3, ...)cost less than 10 Euro for 25Kg here in the Netherlands.

[Purple Fire]

Vonk: I too buy my KmnO4 from pharmacies, but I get it for $4.40 per 25g I know its very expensive, but I dont use flash all that much. My Al I get for free from friend who owns a diamond cutting too business. They make a composite with powdered Al powdered Cu bonded with a resin and some other funky shit. They use it in such HUGE quiantities that he is perfectly happy to give me a scoop every couple of months :cool:

If you found another industry near where you live that uses large quantities of Al powder, you could probably just wander up and say "I am trying to get hold of some Al powder for an extra-curricular(sp?) chemistry project and was wondering if I could buy some off you"...try it, see what they say.

Isn't getting hold of chems in NZ a bitch :mad: !!!!

<small>[ June 30, 2002, 06:29 PM: Message edited by: Purple Fire ]</small>

[JohnDoe]

i've never tried making a triangle cracker because all i have is bp and i never thought it would work. i guess i'll try it now.

[vonK]

You should have more faith in you BP, mine works great. You should get a nice deep report. I think the only problem with BP is that you get no visual effect, just a bang, no flash, at least that's how mine works.
Purple Fire, How long ago did you buy your H2O2?
I'm assuming you bought it from the hydro store in Silverdale.
It's just that I'll be in there tomorrow (Tuesday).
He's a friendly guy, in there. I bought some nitric acid from him last holidays.
I've actually been finding it easier and easier to get chems.
BTW, not forum related, but do you know where Rosehill College is?

Cheers
Kurt.

[kanbayat]

I personally love triangles as opposed to tube salutes. anything will go boom in a triangle type. even coffeemate and pidgen shit...lol(not kidding)..the mexicans I believe are the ones that came up with these,and they still sell the ones that will remove most of a hand !..I live very close to the meican border. I have tried just about any known oxidizer/fuel mix imaginable in the fun little things,that remind me of those footballs we made in jr. high..lol
70/30 flash is amazingly effective with these,but so is bp,plaster of paris/al/supher with a matchhead igner or first fire. I have seen triangle crakers in thailand,vietnam and korea as well..but the mexicans make the most powerful I have seen of the commercial variety. even a standard mix of perclorate/sulpher/antimony sulphide/woodmeal and nitrae with work nicely...It is so close to the 4th..unfortunatly all fireworks are banned here..sure miss the little devils.!

[TheBicher]

I bought a few of those mexican triangles out of curiosity of how they are made, and found they do have a really good boom, though it sounded a lot like a balloon poping, but louder. They are just made out of newspaper (I didn't cound how many layers) with some kind of adhesive and a short fuse sticking out. I emptied out the powder and it looked like standard flash about as much as two nickels stacked. The thing with the flash was it looked like there was a lot less aluminum in it, also it was harder to light with a lighter, though it worked flawlessly with the fuse. I found this strange, but it produced good results so you might want to try reducing the aluminum by a lot. That will make them less friction sensitive as the ones i had didn't pop if i threw them on the ground or threw a weight on them. Another thing is the short fuses. I suggest using a longer fuse because a lot of the time kids get scared by these things and they do light quickly so it will be a plus if you use long fuse (also it makes them look higher quality, especially if you use green fuse and not the cheep looking white fuse).

[oryp69]

thye are called polumnas...and if you have 400 mesh aluminum, you should mix it 70:30, potassium perchlorate:aluminum by weight (standard flash)...it is more powerful than the potassium permanganate flash, and if you buy the potassium eprchloate from <a href="http://www.pyrotek.org," target="_blank">www.pyrotek.org,</a> you can get it cheap if you buy it in bulk (sumthing like 4.95 a pound for 10 pounds)

[vulture]

Perchlorate flash is by no means stronger than permanganate flash, permanganate is a much stronger oxidizer and needs much less heat to release it's oxygen. It's just safer with sulfur, but weaker.
And it's not because it's a standard flash used by pro's it's the most powerful.
Besides, permanganate has endless legal uses, whereas potassium perchlorate can only serve one cause....

[oryp69]

i have both and i have tested both, and perchlorate works better than permanganate...also, i havge heard that permanganate degrades or sumthing, i ma not sure, and also i am not sure if it is true, but i have heard taht it isn't a good choice because it has a tendancy to loose it's power to oxidize after storing possibly because it is so soluble in water?

[endotherm]

<small>[ October 15, 2002, 04:06 PM: Message edited by: endotherm ]</small>

[kanbayat]

for somre reason almost all mexican fireworks are made with newspaper,..lol..ecept the tube salutes(m-80 look alikes).
they have the long giant fircrackers they are red and bout 4-6" long with a paper fuse, made outa newspaper,they are even end fused,but about 3/8" dia.
the al they use in their triangles ,looks like paint grade to me. It's a dull grey and hard to ignite. when put in a stiffer paper than news print it gives a deeper thump.You must have gotten some of the smaller triangles,as I have gotten some,that are 3" across amd are quite powerful. I'm not sure what firworks companies are in mexico,but m-80's, and all the rest of the big fireworks are readily available. even 4lb rockets are legal. As I mentioned before,the triangle when properly made will alow almost anything to go boom..have fun this 4th..ppl.

[Purple Fire]

endotherm: Good on ya!!! I have exactly the same book infront of me now, its what prompted this thread in the first place! I was also going to post the Triangle Cracker section, but you beat me to it :p

vonk: Yeah, I get my HNO3 and my H2O2 from there as well. Hes a real nice guy, and he's fully convinced that my parents or me or both are growing weed. I think there is more weed in Silverdale than there are daisies :D I bought my H2O2 about a week ago: $55 for 1L of 50%, wait, its Tuesday today so I dont think this will be much help to you,sorry. Course I know where Rosehill is, I supose you know where Rangitoto is? :D

I think I'm going to try some 70:30 KmnO4:Al flash now, I've never really liked the idea of putting sulfur in the stuff, even if it does make it easier to light.

Speaking of short fuses, I'm not sure how short the Mexican ones are, but mine are pretty damn short cos fuse is not something I have just lying around :( i manage about 3mm for ones for personal use, but make them a bit longer for friends etc. (about 10mm max) I think if the fuses are shorter, then you are permanently caught by surprise, as oposed to sitting and watching it burn on the ground for ages. The little bit of a fright you get gives you a nice burst from the Adrenal gland and makes the bang seem more impressive. Thats my theory/excuse anyway :D

Im finding that Im actually having a bit of trouble selling them, even if they are good. I gave away about 10 to get people interested, but no one really wants them at the moment. When Guy Fawkes turns up however, I'm sure they will have quite the reputation. I think i can probably make $200-$300 over the weeks before and after even if it does mean loosing a bit of sleep :cool:

[TheBicher]

I guess you are right about the element of surprise thing, didn't really think of it like that, so I take back what I said about the fuse length. Also, the kind I had were what I would call "average" size, which is kind of small. I also got some crappy bottle rockets, but nothing to learn from them. Hell, half of them exploded on the ground (in a cup, too, not stuck in the ground), and they didn't even have color.

About having few buyers, I think it really depends on who you find to sell to. Since it is near the fourth just hang out near day camps and the like, and don't be hesitant to ask anyone to buy them. You never know when you will run across the aspiring little pyro who buys a lot.

Anyway, back on subject, that looks like a good book, anyone think they could scan it? (Excuse me if it is allready on the FTP, I have not yet recieved my login information.)

[Purple Fire]

I just made some 70:30 KMnO4 flash, and it wont light!!!, I was expecting it to be difficult, but not even really good visco will light it! Ive tried it unconfined, lightly confined and really heavilly confined, and it adamantly refuses to ignite! What the hell have I done wrong? Should I add some sulfur to the mix to make it easier to ignite? or more Al? or even MORE KMnO4?

Any help'd be really appreciated, cos I really dont want to have wasted all my KMnO4! :mad:

[vulture]

Did you use a solvent to mix it? If not, use acetone. If you did, did you use alcohol? If yes, you've wasted it.

[Anthony]

Put a small piece of tape on the end of the fuse containing BP or some other fuel/oxidiser mix like KNO3/sugar, this will ensure ignition. I used to have some trouble lighting KMnO4 flash with sulfur relaiably with 1/8" visco.

[Purple Fire]

No, I didnt use a solvent, should I have? Should I just add some acetone to the mix, then regrind it? stir it? I've heard of making flash using solvents, but I've never got round to readign up on the details. Is it recrystalising the KMnO4 as very fine crystals that are very intimately mixed with the AL? This sounds promising, I think I'll have to do some research :) anyone know a good place to start (other than searching the forum)?

[kanbayat]

I have never had any trouble with igniting flash. It can be sleigtly difficult to light a small pile of the powder, I usually place a match head in it and light the match head,but I have never had a misfire when confined..this is strange. Maybe the chemicals you are using is the trouble.
You could try 66/33 and maybe that could do it.

[Eliteforum]

kanbayat - Where does the 1% that's left go? You said 66+33=99 that leaves 1%.

[Anthony]

Let's not be silly...

[oryp69]

what kind of aluminum are you using?

400 mesh atomized is hard to get to work, but it works very well normally wen confined, but i use K perchlorate, and it may pose a problem if using with K permanganate. that is the aluminum i would guess u have been using if it's not igniting

[kanbayat]

I used to buy aluminum-bronzing powder years ago from crestlite.
It had a rather pleasent oily smell,it would be a bit difficult to ignite. I havent had any problems with AL I have gotten at skylighter though.I f you experiment enough,you can get youre flash to go if a match gets even close to it,but in my opinion the stuf thats harder to light has a bigger boom. Say does any remember westlake corp. out of utah?
I used to buy my pyro chems from them in the late 70's,wonder what happend to them?

[vulture]

The acetone method (as some members like to call it <img border="0" title="" alt="[Wink]" src="wink.gif" /> ) simply consist of adding acetone to the flash until you got something that looks very similar to silver car paint. Then you just stirr it and squeeze the lumps that are in it, which is safe now because friction has been eliminated. I guess it works better with KMnO4/Al/S because the S somehow improves crystallization of the KMnO4 in the fuel mix.

[Purple Fire]

I tried the "acetone method" with a 3:2:1 mixture, and its now drying :) From what I can see, there is a brown slime now sitting on the bottom, it still smells slightly of acetone so I'm leaving it to dry fir a bit longer. Is brown goop a good thing? It looks remarkably like really old flash, where the permanganate had broken down <img border="0" title="" alt="[Frown]" src="frown.gif" />

[Zambosan]

I think the main reason S makes the "acetone method" work better is that it is a crystalline solid with lots of voids, while the aluminum fuel component has at best a rough metallic surface. So the oxidizer recrystallizes inside the porous sulfur structures, which have an awful lot of surface area. The large degree of direct contact between oxidizer and fuel molecules greatly increases the probability that a source of heat is going to start a chain reaction, hence better ignition characteristics for the flash as a whole.

[Wcc445]

I was experementing with triangles the other day. I purchased some aluminum duct tape (actual duct work tape, not the flexible grey stuff.. look in the duct work section of your hardware store). I tore off a 4 foot strip of it, folded the corner up, inserted the fuse, and sealed the open edge of the pocket with a small piece of aluminum tape. I then proceded to fold it as normal. This makes a MUCH louder report than anything I've been able to produce with paper. I can produce the same report (or louder) as a paper 70:30 flash salute with BP doing it with this method.

Also, has anyone tried adding a bit of Mg to the mix to incrase the flash?

[Energy84]

I've always made mine with Mg/KNO₃ and it does give off quite a blinding flash at night.

[NickSG]

Wcc445. what ratio are you using with the kno3/magnesium, or are you asking about adding magnesium to black powder or pre-made flash? I use the 6/4 ratio kno3/magnesium, and it works perfectly in my polumas, and many other salutes.

[Wcc445]

I don't have any Mg powder right now, actually. What I did was made 70/30 KCLO4/Al flash, filled the salute with it about half way, cut some Mg ribbons into a few around 1/8" square pieces and placed them inside the salute, and filled the remaining space. I'm sure it would work alot better with a bit of Mg powder, or use a flash formula containing Mg.

I got quite an impressive flash with this salute. I wanted to get some opinions about the Mg before I bought some Mg powder.

Wcc

[NickSG]

Whenever i want magnesium powder, i just cut thin pieces off of a magnesium plates, or flatten a firestarter and cut it into small peices, and then i run them in my ball mill for several days. If i am to impatient, i just take a knife, hold the blade on the block at a 45 degree angle,and scrape the block up and down really fast. I get about 150 mesh magnesium powder, and when mixed with KNO3 in the right proportions, you get a nice flash powder that can burn almost as fast as black powder, but its burn rate is multiplied when in a colsed container. It is slow, and you have to have strong hands and biceps, but right now i can get 1 teaspoon of powder in about 10 minutes, which isnt that bad.

[Energy84]

I do the same thing with firestarters, except that I file them instead of using a knife. It yields a nice enough product, with finer meshes being produced using finer files. Only problem with that is that it takes so much longer. Right now I'm trying to figure out a way to collect the dust if I were to use a belt sander. I have one that's mounted to a table, but I there is so much waste that it's hardly worth it. Mg isn't magnetic, but maybe there is someway to capture it using static electricity? I was thinking of applying a voltage (+) to the bar being sanded, and then another (-) on a sheet of paper or something? Anybody think this would work?

[NickSG]

i used to use a belt sander to grind my aluminum and magnesium. The only thing bad about it is that both metals are very soft, compared so most other metals, and after a couple of minutes, the magnesium or aluminum will get stuck in between the groves. It produces very fine powders, close to 400 or 500 mesh, but only if you can find a fine enough wheel. Anyways, i just got done making some magnesium flash powder. After i gathered about 1 teaspoon of the magnesium dust(about 150 mesh), i poured it in a film cannister with 10 or so 3/8 inch steel sling shot ammo, an shook it around for a few minutes, and when i poured it out, it was a lot more finer, about 200 mesh. I mixed it with KNO3 in a 6/4 ratio, and lit a 1/4 teasppon with a long punk. It burned very fast, much faster than a remembered. /4 teaspoon burned in about a second, and it was very bright. I made a poluma, using 1/4 teaspoon of powder, and i am planning on lighting it soon to see how well it does in polumas( i already know it works very well in tubular salutes, and cherry bombs, but i dont remember trying it in polumas).

Edit: And when i did use a belt sander/bench grinder to powder my metals, that way i collected it was to hold a 1 gallon zip lock bag right where the powder usually shot out. THen i would lay a few sheets of paper around, so that if any dust did escape, it would fall onto the paper, and i would later collect it. Be very careful not to get the bag cuaght in the rotating belt, and make sure to always wear a surgical mask, so you do not breath in the dust, which can seriously mess up your lungs.

<small>[ January 23, 2003, 09:37 PM: Message edited by: NickSG ]</small>

[Anthony]

An easy way I reduced a block of Mg was with a polythene bag and a dremel. I fitted a fine sanding drum to the dremel, held the block inside the bag with one had from outside the bag. Then put the end of the dremel into the bag and gripped the neck of the bag around the dremel with my other hand and sanded away.

It's virtually sealed, so you lose no powder and you don't expose yourself to an inhalation risk. Dremels also typically produce a nice fine powder.

It's unlikely, but you might want to open the bag carefully on the off chance that the Mg has become pyrophoric.

[NickSG]

The finest powders i have ever got was with my ball mill(it is actually a rock tumbler i bought at wal mart for 30 bucks, and it works perfect). I am sometimes really bad at guessing mesh sizes, but when i left 25 grams or so of magnesium strips(1/8 by 1/8 inch) in my ball mill for 2 weeks, it was extrememly fine. It was finer than the 600 mesh aluminum powder i bought from United Nuclear. I am not sure of this, but i guessed around 800 mesh. It takes a lot longer than most other ways of getting magnesium(or aluminum powder), but since i am just making my fourth of july stash, i can take my time, becuase it is so far away.

[Wcc445]

With regards to the dremel, you wouldn't want that Mg powder getting in the dremel motor.. seems like it could ignite.

Wcc

[Anthony]

Obviously you don't put the dremel so far in that the vents are inside the bag :rolleyes: Only enough for you to hold like a penci-grip needs to go in.

[skinny]

try rapping your triangles in a few layers of duck tape this improved the sound alot for me.

[NickSG]

You dont have to tape all of your polumas. I usually depends on what composition it being used. Flash Powder burns very fast, and produces much more gasses than most any other LE, so the walls do not have to be thick(but thicker is better), but even with thick cases, it will still fragment the case into small peices. Tubular salutes are made that have no end plugs, just a peice of tape on the end so the powder is kept from spilling out. The demintions are weird (14 inches long, 1/4 inch ID and 1/16 walls), but when they explode, they produce ear shattering reports. Anyways, i do tape my polumas with tape, becuase it burns fast, and produces enough gases to burst the container, but isnt like flash powder. Black powder, unlike other powder, usually doesnt have enough power to burst the walls of a taped poluma. Results may be different, and BP may work fine with every other person but me, but it usually doesnt burst the walls of a well taped poluma like other composition would. Without tape, the walls are flimsy, and a loud report isnt produced, so if you plan on using BP, i would just make a tubualar salute(unless you can make them good enough to make black powder burst the container).

[andreas]

3KClO4+4Al--&gt;3KCl+4Al2O3
KClO3+2Al-&gt;KCl+AL2O3
If you atleast mean chlorate or perchlorate aluminium flash.
Flash does not produce more gasses than for instance black powder, in fact it only produces solid materials, of wich a small amount probably sublimates.
The fact is that flash burns so quick and hot that it heats op the gasses trapped in the cracker so fast that it expands faster than the speed of sound. Similar to lightning. By the way nitrocellulose does do both and is far more superior for crackers if made correctly. I'm wondering of topic now. :D

<small>[ January 29, 2003, 11:22 AM: Message edited by: andreas ]</small>

[NickSG]

Nitrocellouse can be hard to make a loud boom with, and is usually less prefered, but if you make it right, like you said, the results will be impressing. But if you decide to make a bomb out it(i hate using the word "bomb", but what i mean is you want it to detonate) then it will work fine, you only need a well made 3 gram AP firecracker. Also, make sure to use doublebase, it works better.

[fasa]

I have a problem with polumnas...

I make them with grocery bag paper and glue, and wrap it around 4-5 times. I then put around 6 layers of ductape around it. I use BP. When i light them with the regular fuse, they spit out a lot of fire, but don't explode or make a report like I would like them to...
With electrical ignition, they pop, making the sound of a popping balloon, and fly a few meters with a spark tail.

I tried some with flash powder (50\50 KNO3\Mg) but it just shot out some sparks.... nothing else...
(I also tried some with a mix of BP\KNO3 + Mg\Sulfur + Pottasium Permangate (sp?)\Barium Nitrate + Aluminium, the mix is really nice, it makes various colors and all, but in a polumna it just propelled the polumna after making a pop that isn't any louder than a balloon. I don't see how this is possible, because the polumna was around the size of my hand...)


Anyone know what I did wrong? or how I can improve my polumnas?

Thank you!

[Anthony]

The problem is you're getting an insufficient pressure buildup - it's escaping too fast compared to how fast the gas is forming.

It could simply be that your compositions aren't burning fast enough, but considering how many and the particular ones you've tried, it's unlikely that they *all* suck.

Are you wrapping the paper strip tightly around your fuse? Are the corners sealed? How wide is your fuse? Normal visco isn't a problem, but you might be using an improvised fuse that's leaving too large a hole in the polumna once it's burnt inside.

Maybe try leaving off the tape, just use a piece to secure the loose end of the paper strip, and maybe a strip along the bottom edge to secure the corners. Deliberatly weakening the polumna in this way might give you better results.

[fasa]

I tried something new....

I made a polumna out of normal A4 paper and BP.
I wrapped the paper 4 times around, and filled 80% of the polumna with my homemade BP.

I used a sparkler as a fuse.
One other thing I did was; I took a hot glue gun, and sealed the holes of the triangle, while giving extra attention to the fusehole.

This gave a pretty nice, low pitch report. Not as loud as I think they should be, but it's an improvment ;) .

I am going to try some new things like making the polumna out of aluminium foil, and using less tape....

I'll post the results when I am done...
Thank you for your tips!

[NickSG]

When I started out, getting BP to work in polumanas was really hard for me. The ones that I taped didnt even pop, just shot around. Then I started putting a drop of glue on the peice of paper right before I folded it, making the case a lot stronger. They started making louder noises, and when I sealed the corners with super glue, they were just as loud as regular tubular salutes.

When you are not using tape, try to use the stiffest paper possible. When the BP ignites, its gases press against the walls, and if the walls are flexible, they stretch and the gases are simple blown out of the fuse hole, since that is the quickest way out.

Newspaper works well for me, but you have to glue strips of newspaper together to get the right amount of confinement needed to produce a loud report.

I never had any problems getting KNO3/magnesium flash powder to work in polumanas. Maybe your chemicals arent fine enough, but with 400 mesh magnesium my KNO3/mg flash is just as powerful as the standard 7/3 flash powder.