[mrskeet410]

I saw a show on one of the cable stations (Discovery Channel?) about explosives. The showed a part in which they were using high explosive for underground hard-rock mining, or maybe just for tunneling.

Your basic drill the holes, wire, cap, andstuff, the charges, then connect everything to the primer cord. Nothing unusual so far.

Then they went outside, and things were different than I expected. They didn't connect wires to an electric detonator. They said they were too dangerous, radio waves, lightning, etc. What they connected to was a device that held a shotgun primer, and a 'hammer/trigger'. When they pulled the 'trigger', the primer fired. Actually they had to do that twice. The first was a dud, but I couldn't tell if the primer misfired; or if it fired, and didn't detonate the explosives.

Now this is the interesting part to me. They just fired that primer down what they called a simple plastic tube. It certainly looked like that.

Now my question. Was that just a hollow tube that carried that charge several hundred feet? That doesn't seem possible. Or does the tube contain some sort material to carry the charge to the blasting cap?

 

[Bob Schultz]

The firing of the shotgun type primer (its actually about double the strength of a 209) sends a pressure wave down the tube which drives a piston into another primer which detonates the cap which fires the charge. Its a very safe and usually reliable system for mining operations where the possibility of static or lightning could set off an electrical detonation system accidentally. It may take several days to lay the charges in a mine with literally hundreds of yards of distance in the explosive grid. Having primed electric detonated charges laying around for a few days in the weather leaves a lot to be desired.

 

[mrskeet410]

Thank you Bob

 

[Rollin Oswald]

There is no limit to the knowledge available on this site.

Rollin

 

[Mac V]

The primers may have been double strength but the shooter was taking them right out of a Remington STS 100 pack.

Mike

 

[thedemoguy]

Why wouldn't they just use det-cord ?

Bill

 

[Bob Schultz]

The reason they may have had a dud the first time is the use of a STS primer. American target shotshell primers have a low briscience (flash/power) level for use in target and light hunting loads. Suprizingly, the primer can have an effect on recoil due to the burn rate of the propellant and how fast it lights up the powder charge. If they would have used a hotter primer (like those the explosive people sell...) they would probably not experience any duds. I'm sure the ones sold by the explosive suppliers are five times more expensive than regular 209's, I'd probably use the Rem. primers too!

Bob

 

[famill00]

I would use Fiocchi primers. They are cheaper!!

 

[GunDr]

While we're on the subject of ammo components for other uses....

I watched a movie a while ago Flight of the Pheonix. The airplane the guys rigged together, started with the use of a shotgun shell, I assume was a blank. How does this work?

Doug

 

[Baron23]

I don't know about F-15 and 16...but in addition to the old radial engines of bygone years, up to the F-4, they also had a cartridge start system for front line jet fighters....not used unless necessary since it wasn't great for the engines, but it was a sight to see. The preferred method was to spin the engine up with a with a blown air cart.

Cheers

 

[GunDr]

So this fly wheel spins freely after the shot, then it's engaged to the crank? Kind of like "poppin' the clutch?"

 

[Brian in Oregon]

Ever see a Republic F-105 Thunderchief start up? The jet engine is started by a very large blackpowder cartridge. Creates a HUGE BY LARGE black smoke cloud. The first time you saw it, you thought the plane caught fire.

 

[mrskeet410]

jim forsbach - Wazza squib?

 

[mrskeet410]

Brian in Oregon - What do you hear when a F-105 augers in?

 

[mrskeet410]

Since Brian in Oregan's radio isn't working, I'll answer my own question.

Thud!

But I'd still like to know about a squib.

 

[K-80 Jim]

A squib is a small intermediate charge to accelerate the main event.....usually in canon loads.

FIRE IN THE HOLE.......


Jim

 

[mrskeet410]

Thud, get it? Hmmmmmmm? That's a joke.

Hmmm, airdales must not like it. Waddaya expect from folks that have to dress like bus drivers.

 

[NintyT]

Okay, here's the deal. That "hollow tube" you mentioned is actually a non-electric or "non-el" lead (promnouced leed) line. This tubing has a light dusting of RDX, a powdered explosive. I've set off many of these charges, and have used all brands of 209 primers. Never a failure to fire. The RDX detonates at a rate of approx 6000 feet per second. At the end of the lead line, you'll find a non-electric blasting cap.

The advantage over this system is control. Electric systems can be affected by static, broken wire, thunderstorms and such. The old burning type fuse cannot (or at least should not) be stopped once lit. The non-el allows complete control until the moment the primer is fired.

 

[mrskeet410]

Good info, ty nintyt.