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View Full Version : Firecracker- "Double-Voiced"


Cobalt.45
September 19th, 2008, 12:46 PM
There will always be those who oppose ground salutes for one reason or another.

Some might even say that there's no legitimate use in professional pyrotechnics for them.

To them, I say BAH!

View this little number and see what you think:http://uk.youtube.com/watch?v=Eezw2xpCH-o&feature=related

With that as your inspiration, give these a try-

DOUBLE VOICE CRACKERS
Inspired by "AJS" BAFN II

These crackers are a simple 2 hour, start-to-finish project. 12 in an hour easily, after you have the tooling made.

Picture a tube. Somewhere near the center is a clay plug. Through the clay plug is a piece of visco. Picture tube with plug, fuse ends are sticking into each half of the tube. Now imagine filling one half with black powder and sealing with cardboard disk and tape, and putting a healthy amount of flash powder in the other end, then also sealing with disk and tape. Put another piece of visco through the sidewall into the black powder, stand the tube on end black powder side down, light fuse and retreat. The black powder charge lifts the device to 50 feet or so and about then the flash goes off. The height of the second bang really adds to the echo effect

Length recommended is 4". Recommended ID is 5/8”. Cut one piece of 5/8" dowel about 2-3/4" long. Drill a 5/8" hole about an inch deep in a 2X4. Glue in the dowel. Drill a hole in the top center 1/8" by 3/4" deep. This can be done without a drill press but is easier with one. You are done building the ramming nipple. Next, the ramming drift is cut about 4-5 inches long with a 1/8" by 1-1/4 " hole in one end. The hole edge should be counter sunk slightly. Do it, you'll thank me later.

Let's make some. First, cut a piece of visco about 2-1/4" long. Angle cut the ends. Put the visco in the ramming nipple drilled hole. Place a tube over the nipple and put in enough powdered clay to get you a 1/2" plug after ramming.

Now we have to fit the ramming nipple into the case and get that pesky piece of visco to fit in the 1/8" hole we drilled. The bevel helps, as does making the visco as straight as possible . This is the only (slightly) hard part of the whole procedure. Rap the drift sharply with a hammer as you would to ram a clay plug in any device. A non rebounding, like a dead blow hammer, works well for me. I like to feel just a slight bulge on the outer wall of the case, then I know I've "set" the plug.

Take the drift out, remove the case from the nipple, shake out the loose clay and peek inside. Amazingly the visco looks fine, the little bit of dust on the ends of the fuse doesn't seem to affect ignition.

I always drill a 1/8" hole in the side of the case next. I try to line up the side hole near the end of the visco inside the tube. When I put the ignition fuse into the side of the cracker I try to keep the two ends close together and hot melt around the fuse on the outside of the case to keep everything lined up and in place. I don't know if it is necessary, but my first cracker worked so well I've never tried any other way.

Fill the fused side (which in my version is the larger cavity) with 2F black powder.
Seal the end with a cardboard disk or two. The total thickness should be about that of a dime. Put two pieces of 1/2" wide filament packaging tape over and down the end. Then take a wide piece of masking tape and cover it all up.

The other end cavity can be filled with whatever strikes your fancy. The real crowd pleasure is still a dose of good 70/30 flash powder. You DO NOT fill the end to capacity with flash. I use ONE scoop made from an empty 9mm cartridge, and they are quite loud. After filling the 'payload' end of the cracker, seal the end with another disk and some more masking tape. Filament tape isn't needed for the flash end if you have a decent flash powder.

They have a tendency to tip so you might want to make a holder/base of some sort. To fly right the cracker must be placed UPRIGHT on a solid hard base.

-=HeX=-
September 19th, 2008, 04:09 PM
Wow! That is an amazing find Cobalt.45! Once I get back from the wilderness that I currently am in, I will get the materials to do this project. It sounds like just what I need, a substitute for small aerial salute shells for small displays. Also, such a salute is perfect as a diversionary device or as a simple flash bang device. Once I perfect it I may even scale it up a bit...

Would simple meal powder work instead of the commercial powder? Is permanganate flash too sensitive to be used in the 'second voice' part?

Cobalt.45
September 19th, 2008, 08:41 PM
Would simple meal powder work instead of the commercial powder? Is permanganate flash too sensitive to be used in the 'second voice' part?Your homemade meal should be fine, I would rice it first is all.

I don't like using potassium permanganate but it should be fine if not stored and all other precautions are followed.

The WWII "Bouncing Betty" come to mind...

Alexires
September 19th, 2008, 09:50 PM
Cobalt, I note that you say it needs to be upright to be effective. Those punching dolls with a weighted base come to mind.

If you were to make a half sphere of perhaps plaster of paris and epoxy your DVC (Double Voice Cracker) to the flat part (ensuring the half sphere is wide enough that it will stand up by itself) then regardless of how it falls, it will always return to an upright position.

Cobalt.45
September 19th, 2008, 10:29 PM
If you were to make a half sphere of perhaps plaster of paris and epoxy your DVC (Double Voice Cracker) to the flat part...then regardless of how it falls, it will always return to an upright position.Sure would!

You would want to mold the hemisphere to the DVC like a skirt, leaving the bottom of the DVC exposed to allow it to lift.

The pulverone lift charge would need to be adjusted for the increased weight of course. The plaster skirt would reinforce the lift chamber to allow hellacious amounts of BP lift to be used before rupturing the device.

But yea, that would allow it to be lobbed quite a distance.:cool:

Bacon46
September 24th, 2008, 07:53 AM
I think what Alexires meant was if you attach a hemisphere without a hole to the tube it would act as a flat launching surface and be left behind. That way it wouldn’t affect the height. A small amount of hot melt glue would also do the trick, enough to hold it to the base but not so much that the black powder blows the tube apart.