13 replies to this topic

[king lerock]

hi, recently i was burning some fairly poor quality bp (lots of smoke slow burn time) and i had put i small spatula full down ignited it and it formed a perfect smoke ring. is their anyway to recreate this, i know its no use in fireworks but it would be brilliant to show of with.

[spanner]

This is a snippet from Lloyd Sponenburgh (denizen of rec.pyro, author of the "ball mill bible"):

SMOKE RING GENERATOR
Toroidal vortices are easy to make. In the simplest apparatus, only a "rough" cylinder is used -- like a 55gal steel drum (or even a fireworks mortar). The inside surface must be irregular enough to impart a good amount of friction to the sides of the rising gas column.
The best apparatus uses a "lipped" cylinder, with an exit hole smaller than the cylinder's inside diameter. The ratio of sizes is not critical. I've seen it work well with a mere lip of an inch or so on a 20" diameter gun, and a hole as small as three inches on the same equipment.

The ratio of height to diameter of the cylinder is the more important factor. Cylinders approaching a ratio of length over diameter of infinity work best. Of course, reality makes ratios over five or six to one impractical.

(In practice) One fills the cylinder with dense smoke, then fires it with a small, sharp explosion on the bottom -- the end furthest from the exit. The gas expansion moves toward the opening, moving in more or less linear fashion near the mouth. As the stream encounters the lip, it is forced into an outside-down-inside-up toriodal(sic- toroidal?) vortex.

The higher the initial rotation rate, the longer the vortex will last. By achieving a high rotation rate coupled with a slow forward travel, you have a vortex that will stand a long time, and remain visible. Often the vortex will continue even after it has spun all of its smoke away by centrifugal force.

Don Herbert (Mr. Wizard) published a "smoke ring cannon" design in his weekly children's newsletter in the fifties. It consisted of a paper oatmeal box with a nickel-sized hole in the lid. One filled it with (gads!) cigarette smoke, and thumped the bottom with a finger to launch it. You could blow out a candle at ten or fifteen feet with the vortex. LLoyd
END

I've noticed that phenomena myself while burning small piles of BP. And it always causes me to stop and watch it as it rises and fades away, always fascinating.

There was a video on the net a while back that showed a guy shooting rings from a 55 gal. drum. They were way neat, didn't get the specifics, though. I do recall that having the charge at the bottom center did not seem to be necessary.

PS- Alas, Mr. Wizard has passed away (July 10, 1917 – June 12, 2007)- one of the true inspirations to a generation of youth. RIP, old son...

[Asteroid]

One way you can do it is by filling an airzooka with smoke and then firing it. The ring will travel a good 10m indoors but outdoors the wind will destroy it in no time, even if it's only light.

[king lerock]

i have an airzooka but what would you recommend i use for the smoke?

[Creepin_pyro]

What kind of scale are you looking at?

Something like this?

http://www.pyrobin.c.../gas mine_1.wmv

[king lerock]

no im working on a much smaller scale right now. safety first and all that.

[Creepin_pyro]

Howsabout this then?

http://www.amazon.co...s/dp/B000FAIY1M

[Asteroid]

A normal smoke grenade would work fine, but anything with a similar effect should work. I have even done it with water vapour.
If you replace the smoke with gas (propane etc) then theoretically you can create a fireball (mind you don't ignite it in the airzooka) by firing at a candle. I imagine you might have all sorts of issues with this though.

I will try and get a video/photo of it with smoke at the weekend (time permitting).

[portfire]

This may help

http://home.comcast....vger/index.html

There's quite abit of info out there on Ring Vortex Generators. I looked into it a while ago and was going to build a small one, but then decided to make two 7 shot Roman Candle's

I did try and build a Tornado gernerator once but I'll not go into that!!

Edited by portfire, 10 March 2009 - 03:48 PM.

[pyrotechnist]

I once made a low quality BP as well that used very coarse grains of willow charcoal just to get rid of the stuff. When burnt it would sputter and create a lovely formed smoke ring and then go out again to repeat it 5 or more times creating these rings until I was left with nothing but smoldering ash. I have yet to achieve the effect again!

[king lerock]

well, i have ordered the zero blaster now and iwill use it as a starting piont, by the way im thinking of instead of large fire works ect i want to do things like this, small trick that you can show of.

[Thudkaboom]

I have built two smoke ring canons. both from blue plastic chemical barrels you find at farms and all over the place. Just cut the desired size hole in the bottom. I used the very same design as the Airzooka using bungee cords with hooks and a strong plastic membrane. I have also used a brass cup attached inside which is where I place plumbers smoke pellets. They both have harnesses so I can wear them and fire rings like a gun. Some plumbing merchants supply coloured pellets but I am having difficulty sourcing them. For use inside I use a pungent dhoop style incense which is a sticky solid sold very cheap on the net along with charcoal discs. Smells lovely and smokes very well indeed.

Questions welcome.

[Asteroid]

As a pyro, you must know that they can be made cheaper yourself! those smoke pellets work out very expensive!

[Thudkaboom]

As a pyro, you must know that they can be made cheaper yourself! those smoke pellets work out very expensive!

You're not not wrong there mate. I've just started making some coloured smoke generators which are working fab'. Although, the dyes can be a pretty penny. I'm still searching for reasonably priced dyes.
My giant smoke canon is being used in a carnival this weekend for an Alice in Wonderland float. It's for the catapilar on his toadstool. I'm using Indian dhoop on charcoal discs for the rings and colour changing rainbow smokes for his hooka pipe. Can't wait.