Fuse timing & Shock tubes

[oldguy]

These are common in the mining industry.

Never seen either used in fireworks, but thought I would make mention here of both.

 

There is a fuse ignition timing technique common in the mining industry called "Spitter" cord. Which is like a very small diameter fuse, except it is flexible wire reinforced, burns off very hot (about like slow flying fish fuse) at a precise specified rate (slow 1 minute per ft, medium = 30 seconds per ft & fast = 5 seconds per ft). Spitter cord can be attached to any other fuse via a clove hitch, or twisted in place around the fuse like a twist tie or attached to "Igniter" caps crimped onto fuse ends. Igniter caps look like a blasting cap, with a slot in them, except they don't detonate (they contain a hot primer mix to light the fuse they are attached to). You simply crimp the Spitter cord into the slot on the igniter cap. By spacing the igniter caps at measured intervals along the Spitter cord, you an ignite large amounts of fuse (all the same length), resulting in a very precise sequential fuse ignition.

 

Shock tube (flash powder)

 

Nonelectric Detonating System (Nonel) - is a thin plastic shock tube that has a light dusting of reactive flash powder on the inside surface (approximately one pound per 70,000 feet). When initiated, this tube will reliably transmit a low-energy signal from one point to another by means of a shock wave phenomena much like a dust explosion. It will reliably detonate around sharp bends and through kinks. Because the detonation is sustained by such a small quantity of the reactive material, the outer surface of the tube remains intact during and after functioning. It will reliably initiate instant or delay blasting caps.

 

http://www.dynonobel.com/files/2011/12/NONEL.pdf

Edited February 25, 2012 by oldguy

[allrocketspsl]

These are common in the mining industry.

Never seen either used in fireworks, but thought I would make mention here of both.

 

There is a fuse ignition timing technique common in the mining industry called "Spitter" cord. Which is like a very small diameter fuse, except it is flexible wire reinforced, burns off very hot (about like slow flying fish fuse) at a precise specified rate (slow 1 minute per ft, medium = 30 seconds per ft & fast = 5 seconds per ft). Spitter cord can be attached to any other fuse via a clove hitch, or twisted in place around the fuse like a twist tie or attached to "Igniter" caps crimped onto fuse ends. Igniter caps look like a blasting cap, with a slot in them, except they don't detonate (they contain a hot primer mix to light the fuse they are attached to). You simply crimp the Spitter cord into the slot on the igniter cap. By spacing the igniter caps at measured intervals along the Spitter cord, you an ignite large amounts of fuse (all the same length), resulting in a very precise sequential fuse ignition.

 

Shock tube (flash powder)

 

Nonelectric Detonating System (Nonel) - is a thin plastic shock tube that has a light dusting of reactive flash powder on the inside surface (approximately one pound per 70,000 feet). When initiated, this tube will reliably transmit a low-energy signal from one point to another by means of a shock wave phenomena much like a dust explosion. It will reliably detonate around sharp bends and through kinks. Because the detonation is sustained by such a small quantity of the reactive material, the outer surface of the tube remains intact during and after functioning. It will reliably initiate instant or delay blasting caps.

 

http://www.dynonobel.com/files/2011/12/NONEL.pdf

 

Excellent mate keep it coming Im fascinated

[Potassiumchlorate]

Alfred Nobel smiles in his heaven.

[pyrojig]

Nice..

 

I was always under the impression that shock tube was a finely powdered H.E. ( like hmx petn or rdx) with fine Al added to it. I guess you could call it a "flash powder" a H.E. one, probably not your typical 70/30.

 

It is fascinating how they're able to coat such a consistent thin layer of powder on the inner tube walls..

[oldguy]

I will post more info later.

But, will post it in the HE section.

[NightHawkInLight]

I've seen shock tube used in fireworks displays. The last time was at the PGI in Appleton. I don't know why it was used, it must have just been readily available and fit the need. I was also under the impression that it uses HE. PETN or some such in picogram quantities per meter.

[warthog]

My Uncle, now deceased, was a blaster at a mine. As a boy I was privileged to be able to go to the worksite with him on a number of times. He used these sorts of fusing methods to drop huge cliff faces into the bottom of the pit where they would then muck it out with cranes and such. I wish I had been a bit older when he was still around as I was always fascinated by what he did at the mine.

[Potassiumchlorate]

Great grandma's brother was a blaster as well.

[RogueSwimmer]

Nice..

 

I was always under the impression that shock tube was a finely powdered H.E. ( like hmx petn or rdx) with fine Al added to it. I guess you could call it a "flash powder" a H.E. one, probably not your typical 70/30.

 

It is fascinating how they're able to coat such a consistent thin layer of powder on the inner tube walls..

 

Not necessarily. There is a patent for AP+aluminum. I have experimented with copper thermite with good results in 1/4 tubing. The non HE-based powders including AP/al seem to be under 2000m/s, so I don't know if they can initiate det cords like shock tube can. The latter is what is remarkable, because there is hardly any powder in there and it doesn't even tear the tubing. Quite impractical for amateur use, and I would say quite expensive for commercial use. The consistent reliability of those tubes is quite fascinating.

[dan999ification]

i think 2000m/s is achievable with flash especially if used in this way, it has no mass to work through, the flame front is allowed to move faster in a hollow tube, it will also have more available hot spots than a solid mass of it progressing things further faster. permanganate flash with antimony and silicon?, fine metal powders will coat almost anything, it wouldn't be hard to blow the comp through the tube using light air pressure removing excess comp and leaving a very thin coating of it that wont come off unless its exposed.or physically removed, even a light dusting on tools is still plenty to get a reaction/flash over, ever burned paper used for diapering?

the tube doesnt break because of its strength, the tiny amount of comp inside the low id thick walled tube and that the wave is moving/has somewhere to go, im sure if a short tube was sealed both ends or the comp was restricted from burning in anyway [ filled with comp]youd get a firecracker like reaction that most people would expect rupturing the tube

 

has anyone seen the daylight display recently?, it could have used something like this to get the close timings/ignite 100ft long rows of salutes in less than a second, i think i read that some he was used aswell?

ideal for musical mascletta if you could afford/get some

dan.

Edited February 26, 2012 by dan999ification

[dagabu]

i think 2000m/s is achievable with flash especially if used in this way, it has no mass to work through, the flame front is allowed to move faster in a hollow tube, it will also have more available hot spots than a solid mass of it progressing things further faster. permanganate flash with antimony and silicon?, fine metal powders will coat almost anything, it wouldn't be hard to blow the comp through the tube using light air pressure removing excess comp and leaving a very thin coating of it that wont come off unless its exposed.or physically removed, even a light dusting on tools is still plenty to get a reaction/flash over, ever burned paper used for diapering?

the tube doesnt break because of its strength, the tiny amount of comp inside the low id thick walled tube and that the wave is moving/has somewhere to go, im sure if a short tube was sealed both ends or the comp was restricted from burning in anyway [ filled with comp]youd get a firecracker like reaction that most people would expect rupturing the tube

 

has anyone seen the daylight display recently?, it could have used something like this to get the close timings/ignite 100ft long rows of salutes in less than a second, i think i read that some he was used aswell?

ideal for musical mascletta if you could afford/get some

dan.

 

The one in Dubai? That was 100% E-matches.

 

-dag

[pyrojig]

Maybe some type of adhesive to obtain a light coating of a energetic material that would stay on a inner wall of a tube, I dont know.

 

It seems like even if your able to coat a tube, keeping the coating to stick Via static ( not static electricity) , would not be consistent. Achieving a mix where the oxidizer doesn't migrate out , would be a pain.

 

How did you ( rogueswimmer ) get a 1/4 tube to work in transmitting a blast of thermite comp? It seems far from efficient, and prone to be overly sensitive to static electricity and or ruff handling( inpact).

[RogueSwimmer]

There is nothing static/impact sensitive about copper thermite dust. It does stick to the walls willingly from just sliding through the tubing. Only problem with it was the blowback of that brown smoke through the tube into my hand-held igniter. I never got the blowback with secondary-aluminum mixes, so the thermite was merely and fun experiment.

 

The only good way to make a commercially "comparable" shocktube, in terms of good initiation properties and reliability, is to pour a thinned glue mix through the 1/4 inch tubing, where it coats all the wall surface in a thin mix and then start dropping your secondary through it as it is sticking to the walls. It would need quite a while to cure and dry up and would have high gram/foot mix.....possibly 1g/foot or about 3g/meter. This one does burst the tubing walls a bit, but it isn't quite like det-cord and is relatively safe to be next to.

[Zingy]

Old Guy:

 

Would you by chance know, what makes quarry cord? There have been times, I wanted something between visco and quick match in speed, for special effects. Many years ago, I tried making very fast fuse, according to Weingart's Book, with Potassium Picrate, and it was a complete waste. This was before they had all the varieties of fast fuse, and fast visco today. Quarry Cord was thicker, and more durable.

Edited February 27, 2012 by Zingy

[oldguy]

I have not seen quarry cord around in decades.

As I recall it burns with a hot external flame at a rate of one and one-half feet per second.

I have no idea what it’s composition is.

 

 

[dagabu]

Interesting idea using shock tube and all but Mumpyro from North Dakota used a single 4 ply cotton string saturated in flash (wet and bound with dex or CMC then dried before inserted) and pulled through 1/4" plastic tube (many different ones have been used) , e-matched and plugged (we used BP and epoxy for plugs) at PGI last summer. We copied his design for the fall shoot last year and made a dozen lengths that all worked just like a shock tube with a flame front of about 1000' a second and a nice POP! when lit.

 

The only secret is how to get the coated string down the tube.

 

 

-dag

[dan999ification]

long needle made from copper wire .

funny you should say about the flash quickmatch, after fusing some cakes for nye[ one had visco to qm,tall cake] joining the qm to the visco on the other cakes i discovered that it had a silver comp on it, took an inch a [unwrapped] and burnt it side by side with some normal bm it was twice if not three times as fast and left the tell tail signs of al in the sparks, also shot around like flying fish fuse, very powerful compared to the blackmatch.

 

dan.

[ofpyro]

I've seen shock tube used in fireworks displays. The last time was at the PGI in Appleton. I don't know why it was used, it must have just been readily available and fit the need. I was also under the impression that it uses HE. PETN or some such in picogram quantities per meter.

 

 

We used it during the National Anthem "...and the rockets red glare"... to put up the wall of red. all at once.

 

 

 

oldfart

[dagabu]

long needle made from copper wire .

funny you should say about the flash quickmatch, after fusing some cakes for nye[ one had visco to qm,tall cake] joining the qm to the visco on the other cakes i discovered that it had a silver comp on it, took an inch a [unwrapped] and burnt it side by side with some normal bm it was twice if not three times as fast and left the tell tail signs of al in the sparks, also shot around like flying fish fuse, very powerful compared to the blackmatch.

 

dan.

 

Sorry, no cookie for you.

 

Anyone else?

 

-dag

[graumann]

Sorry, no cookie for you.

 

Anyone else?

 

-dag

 

 

Pressurised air

[dagabu]

Pressurised air

 

SO CLOSE!!!! But alas... no.

 

-dag

[FrankRizzo]

That's what I'd use. Pressurized air to sent a length of uncoated string with a knot at one end down the length of the tube. Once the tube has been "strung", use that string to pull the coated one through.

[dagabu]

That's what I'd use. Pressurized air to sent a length of uncoated string with a knot at one end down the length of the tube. Once the tube has been "strung", use that string to pull the coated one through.

 

They tried that but it is only good to several yards, another just as easy system was used and it worked well over hundreds of feet.

 

-dag

[Zingy]

I am guessing it was done by vacuum, but not ordinary, manufactured vacuum, because of the hazardous particles. I suspect a lab. vacuum pump, or a vacuum created by air or water pressure, if the tubing did not collapse.. Edited February 28, 2012 by Zingy

[graumann]

A vacuum container would solve that issue. As in create a hard vacuum in a vessle, seal it with a butterfly valve, hook up tube and open valve.