Triangular crackers

[Blaf]

Hello guys!

Have you ever seen those triangular shaped crackers elsewhere on Net? No? Well, I've just made some and they're pretty nice. They also go BANG, not too loud though. But let me be quiet for now and hear what you have to say...

Blaf

[Pretty green flames]

Ha, I've probably made around 100 for new years eve 2005/06, I filled them with BP and they were plenty loud. They are great for a quick pyro fix ;)

[deadman]

Yes, I've made them as well. They are called polumnas. Did you tape them?

The first few I made were very light as a used a small amount of flash instead of filling with black powder. This resulted in a self propelled explosive going in random directions. It didn't leave the ground, but it was very interesting.

Also it is better to use thinner than normal fuse to help confinement.

[Nitroglycerin]

Triangular crackers? I know some triangular things that go boom, we call it black bermuda's.
Black Bermuda

On the Dutch part of the forum there probably will be some info about it...

[Oscar]

@ Deadman if you want a better confinement why not glue them and then use extra tape. After I have filled the pocket I glue the rest of the paper so they become stronger. When they are fully dry I don't have to tape them. But it looks better with tape.

[Blaf]

Here is how I did it:

First, see what do we have to get to complete Triangular Cracker. I believe you're all agree with this term – it clearly depictures what we're talking about.

We need craft paper tape, approximately 50cm in lenght and 7cm wide. You can play with these measures at will, just don't make them rediculously big (and loud). Tea spoon comes handy as well as neoprene glue. That white plastic tube lying on my desk contains small amount of KNO3 flash, not so energetic but quite useful. Plastic epruvete with green cap contains precut pieces of my Visco which are primed at both ends. Lets get down on it...


Next we should do prefolding - it makes folding device easier later. It is simple triangular folding like American flag is folded in some grim occasions.


Piece of Visco is then positioned into one sharp end with dab of glue to keep it while folding. Another reason of using drop of glue here is sealing the pocket so that fine aluminium dust doesn't come out.


Just a few foldings should be done first so that pocket stays open at one end...


Now, pocket can be filled with one small tea spoon of flash. See how it glitters inside?


Keep folding the tape carefully so that flash doesn't spill and use glue at each folding to reinforce bent tape. Interestingly, when this goes BANG it cracks at both short sides, long one stays undamaged. The end fold is glued...


And there we go - finished beautiful triangle.


Tell me, how do you like this one?

Blaf

[RSDZ]

Thanks for the explanation!
This way is so easy to remember and it looks very strong!

[Oscar]

I like that idea to glue the fuse. Thanks for the good explanation.

[deadman]

Oscar: You like that taped look? I personally see it cleaner with kraft. Or maybe a little wrapping paper would look nice.

Wow Blaf that is the biggest one I have ever seen. Since I live in California, I see mainly mexican style crackers (more so than commercial ones honestly). They are small with duct or electrical tape and use black powder. So naturally I used black powder and made them small, as that is what I have seen. Flash would definitley be louder. Using flash would prevent me from doing one of my favorite things with polumnas though. Throwing them like ninja stars.

Back to topic, you have a great tutorial every time. I will post some pics of my process hopefully by the end of the week. Also, is that the fuse you get from your machine? It is thinner than I thought. Very nice.

Edit: Sorry now I see it is black match.

[Blaf]

Thanks Deadman for your positive feedback. And yes, that's the fuse I get from my machine but with addition of primed ends. And it works great.

Blaf

[deadman]

Late, as usual, but I do have my pics and process. I decided to make them larger than normal this time. Yes as an American male I do feel the need to compete with anyone else. When it comes to my polumnas, there is no exact science. I go by what "feels right".

The only things I always do when making polumnas are:
>use thin paper
>only glue the last piece down
>use the smallest fuse available

I cut a strip of thin paper to as I said "what feels right".

Unlike Blaf I don't prefold, because after adding powder the folds would change, and with black powder you need to use more and it bulges more than flash would, plus the paper is thin enough to work with.

So the paper is folded like an american flag or paper football, I'm not sure if these are internationally known or done so sorry if you don't know, but Blaf's post explains the process very well. As soon as there is a pocket I put in a scoop of black powder. Again, "what feels right". Place the fuse in the pocket out of the corner with the largest angle.

I glue as little as possible so there is a lot of paper thrown about when it explodes. Anyways it is folded around the pocket without glue. I find it easier to move the paper around the pocket, than flip the pocket over and over again.

Once the last piece of the strip is reached it should be folded over and cut to fit inside the fold it is on. Then tucked into the flap and a small drop of wood/super/wheat glue is placed in the flap as well. If the corners aren't tight enough, also close with glue.
These are my my pics. In order
1. Supplies
2. Strip
3. Powder Pocket
4. Cut End
5. Finished Polumna

[Piet Hein]

Becouse i don't have any flash powder, can i use whistle for a bermuda?

[mr.stijntje]

Sure, it works fine. I've made them too with wistle.
Flash is louder, but whistle makes a sharper bang.

[Guest wolkje]

I've made them last week with BP but the BANG wasn't hard enough
So I made today some new ones with flash, KNO3/S/Al 50/30/20 unfortunatly they sey frrrrlpppr if I detonate them

What did I do wrong, was it the flash ????

Here re some fotograph's

[Nitroglycerin]

The triangular crackers are nice folded, ways better than mine. Your BP and Flash are probably too slow to do their work. The flash and BP is probably burned through the paper when it's still buring. Maybe a heat barrier will help. You can try to make the inside of the cracker a few pieces of aluminium. I don't know if it works, it came up in a few seconds after I had red your post. The best solution is to make better flash I think.

[Guest wolkje]

The folding is just a matther of a triangle with 3 equal sides and 3 corners of 60°
The flash was pressed together in an inox tube with an hammer I smached the mixture together

[deadman]

Yes very nice folding. I have only seen isoscilies triangles, but the regular triangle looks very nice.

I'm not too familiar with kno3/s/al flash. I think Mg is much more suitable than aluminum. What mesh are your chems? Also, what do you mean you pressed your flash? Flash should not be pressed.

[Snooby]

In this case, it's not the Mg or the Al that makes the big different. It's the oxidator that makes the different. I think, for a good traingular cracker, you need a mix that is at least as fast as BP. So use BP, or a real flash, for example one with KCLO3 or KLCO4.

[deadman]

KNO3/S/Mg is a real flash and would work well in a polumna.

[mr.stijntje]

Deadman's right, also without sulfur this is a good and easy ignitable flash. If you've got Mg powder, use KNO3/Mg 6/4, as it's one of the cheapest and strongest flashes you can make with it. Mg doesn't have to be very fine. 50-100 mesh is OK. (that's 150 - 300µm)

[deadman]

I always thought that 50/50 was supposed to be the best Mg/KNO3 flash. But who knows. I believe one of the most powerful flashes is one Blaf could make. KMnO4/Mg. I've read of it self containing at as small of amounts as .5 grams.

[gerjan]

i made a few polumna's myself today, i used whistle 'cause the fly when i use bp.
the were verry loud but my mom doesn't like when i make them:P

gerjan

This is a topic bump without any relevant information. Plus it's such bad english spelling. It makes me feel bad, but I have to give you a warning for this one. T.