Newbie here. A need for propelling confetti with a celebratory firework-like bang: three ideas, but which to choose?

[TSquaredProductions]

I upgraded a New Year's display last year to use air to propel paper confetti, but it seemed very weak, partly because the tank I used couldn't hold as much pressure as I wanted.

My upgrade this year is a partial idea taken from Kipkay on Youtube, with switch-activated glow plug igniters (switches pressed by the display's New Year's Ball when it reaches the bottom) in two metal pipe mortars (2" diameter, 12" length), and some safety devices to keep the glow plugs from staying on too long.

The mortars will be pointed upwards, with ONE endcap on the bottom, per mortar, drilled and screw-tapped to accept the screw-in glow plugs.

As for the propellant, I've been planning and researching one of 3 ideas to try, but two of them are a bit risky, so I wanted to find some hobbyists who had experience in this sort of thing.

Here are my three ideas, from (what I've seen) least dangerous to most dangerous:

1. Flash paper and flash cotton: This is the other half of Kipkay's idea. His project seemed to have a good loud report when ignited, but I also saw another video demonstration from another individual that made it seem a bit weak. (Maybe it was because in the latter, the flash paper wasn't packed down or confined?)

These next two are more dangerous, and I DO want to treat them with respect, but I'm hesitant to approach them, as I don't know if they would give the "powerful theatrical confetti burst" effect and "New Year's firework bang/pop" that I want.

2. KClO4 flash powder (0.5 to 1 gram): This seems to have a nice bang to it, and it may be good for propelling, but I've heard that it loses power when confined. (If used, my plan is to roll the powder in a small wrapper of toilet paper, and use masking tape to hold it to the glow plug igniter.)

3. KClO3 flash powder (0.5 to 1 gram): I know what some of you are thinking. This is the worst of them. This gives me a bit of trepidation myself. It seems more powerful, but it's much more unstable too, and thus risky. This, I fear, may create a danger by damaging the mortars, sending metal pieces flying everywhere, and I don't want that.

What are your opinions on these?

 

 

Edited June 4 by TSquaredProductions

[AustralianPyromaniac]

What you're really making is a "gun/ canon" not a traditional firework. The propellant has the same needs as a propellant in all types of munitions. It must burn relatively slowly allowing time for the projectile to accelerate and generate large amounts of gaseous products with few solids to put maximum work into the projectile. Modern bullets use smokeless powder, which is nitrocellulose which is the same stuff as flash cotton. NC (nitrocellulose) is excellent for this use because it generates 100% gaseous products, and burns quite slowly. Older guns and canons used black powder. I do not think flash powder would work at all, by the time the confetti was halfway up the gun, the explosion is finished and has limited ability to continue propelling the projectile. 

If a pyrotechnic is considered absolutely necessary, I think a quality flash cotton would be best from a safety perspective. The only issue I see with this is flash cotton is not made for this purpose, its burn is inconsistent and somewhat unpredictable. Some samples burn much faster than others, and confinement changes the properties of different samples in unpredictable ways. I have no experience with smokeless powder for an application like this, but it may be a better choice due to its reliability. Flash cotton or any form of NC also will not give a particularly good bang if that is desired. Regarding your comment on compressing it. Leaving it less compressed will give faster flame propagation and a larger bang than compressing it into a chunk. 

If the audience is some distance away, black powder would work well, but it is more dangerous. 

All this said you are using a pyrotechnic powder to create a large amount of gas quickly. There is no need to do this with pyrotechnics. Just upgrade your compressed air system and go that route. What about making a system that uses compressed CO2 cylinders used to pump bike tires? https://www.99bikes.com.au/accessories/pumps/co2-pumps-devices. Compressed air is safer and really will produce a much better result in this case. 

[Richtee]

Stick with what you have in place, by God, You have the infrastructure. Modify/upgrade.

[Richtee]

And, maybe consider a delicate ‘shell” that’ll bust up 30 er so feet out the muzzle. Like a wrap of saran or something.

Edited June 5 by Richtee

[TSquaredProductions]

I also saw others describing the CO2 route on reddit, where I also posted this.

What I'm looking for is not just the launching of the confetti, I'm looking for something to produce a report, a sound to signal the New Year. A burst of air, like a fire extinguisher, is good.

[Arthur]

First look for tried and tested methods on the retail or professional market. In the UK I can buy or rent confetti cannons up to 20" diameter that will lift 20 pounds of confetti 100 feet (expect a clear up cost!). If you are providing SFX for parties then you should have a supplier or ten for any of the sizes of cannon that you could need from 2" to 20", either preloaded with confetti or with wholesale bags of fetti. For NYE you may have to buy cannons because the hire market may all be allocated to regular customers already

Disposable partyware confetti cannons are usually paper/cardboard tubes because card fails into bits of flying paper if the tube bursts, metal mortars fail to flying shrapnel.

Find a source of nice fluttery confetti! I've seen waste paper punchings sold as confetti, it's NOT. It simply leaves the tube in a lump, flies like a lump and makes lumps of mess on the floor. REAL Flutterfetti  is superior, it flies like flying tissue paper and lands as a huge spray then if sits on the floor and gets trampled quickly

[Arthur]

If the sound of confetti needs augmenting for your event then find another device that makes a bang and use both. You get one shot at the right effect so get it right, if necessary by tests done in your workshop. 

People who do pyro sfx get it right every time because they've had lots of prior work and lots of experience. 

Beware safety distances! A stage pyro effect may allow a safety distance measured in inches, while a fireworks safety distance may be measured in hundreds of feet. Design the effect to the safety distances you have.