Boston Bomb triggered by cell phone?

Gunner Asch on Thu, 18 Apr 2013 19:51:34 -0700 typed in rec.crafts.metalworking the following:

Thank crom for that.

-- pyotr filipivich "With Age comes Wisdom. Although more often, Age travels alone."

Sounds vaguely familiar, Ed...

Doctors, airline pilots, machinist, high school teachers? Miners, race car drivers, astronauts, etcetera...

And I love the way you got that "most people" in there.

A majority opinion again?

I'd not argue against that!

But as for the "average person", that's what I mentioned the other day. There ain't no such thing.

People tend to believe that everybody else is just like them, and they are just like everybody else.

Normal. Average. Right.

But everybody can me average. The math just doesn't work that way.

I will, however, allow that there is a strong cultural bias that many people see as "the norm".

So it's something of a shock when New Jersians migrate to Texas and find about about all those "Crazy Texans". :)

You ask around your neighborhood. I'll ask around mine.

Every time you drive down the street you do the same.

THOSE people are licensed too!

Couldn't have said it better myself, Lloyd.

And it applies to them selves only!

Not society as a whole.

Your chances of even SEEING an explosion are vanishingly small.

Except on TV.

And there

Yes, but who's?

Stupid spell checker. It doesn't have a clue what I'm trying to say!

Ed, you area very very bad influence!

I just replied to a 120 line message.

And it's all YOUR FAULT!

The media has put on hours of broadcasting about the bombing, but I have seen nothing that gives any details about the bombs. That may be intentional, no point in inspiring people to build bombs. But I am curious what was the explosive. The fact that the bombs were pressure cooker bombs pretty much says the explosive was not commercial , except it could have been black powder.

So does anyone know what was used?

Dan

Know? Nothing.

Based on the cloud of whitish/grey smoke and the low velocity of the explosion as shown by the videos..black powder or something along that order. It couldnt have been commercial firearms powder..least...its not likely to have been. the blast would have been a higher order and the smoke would not have been nearly white. While the possiblity of it being a commercial firearms powder does..does exist..something fast like Bullseye pistol powder would pressure up fast enough to act similarily...my gut feeling says no..based on the display of the pressure cooker body shown on TV and the lack of a particulate based fireball, which would likely have shown up brightly if a nitro based powder had been ignited. If it had been a nitrobased "gun powder"..the blast would likely have been brilliant as the unburned powder particles were ignited in mid air after the pressure cooker had broken open.

I lost a good friend some 10 or more years ago, who was burning old skunky powder by pouring it into an open flame, a small portion at a time..bonfire. When he decided to rush it..he tossed a gallon glass jar into the flames of the bonfire and the fireball that resulted seared him into a 3rd degree flambe along with his son, who was within

10' of the firepit. And by all reports..lit up the neighborhood like a flare..despite it being a sunny day and mid afternoon.

He lived for another year or two..but was never right after that and soon died.

" snipped-for-privacy@krl.org" fired this volley in news:dea88c27- snipped-for-privacy@m1g2000vbe.googlegroups.com:

Dan, One of my infrequent jobs is to do for-pay forensic studies of fireworks accident scenes, in order to find the cause(s). Part of that involves doing chemical analyses on the various combustion residues in the area.

In this case, I cannot analyze them chemically, but can still evaluate the flame-front velocity, the fireball size, the smoke output, and the smoke color for ideas of what the substance was.

The burn rate and fireball size were consistent with a potassium nitrate or potassium perchlorate-based composition that was fairly fast-burning under the degree of containment afforded by the pressure cookers. Keep in mind, they won't hold much more than about 60-80psi before the break their little lock tabs, so the pressures wouldn't be as high as they would be in a 'real' bomb casing.

Black powder is fairly scarce these days for casual purchases. It's expensive, too. But it can pretty easily be homemade, and can be made to a quality as good as Goex's shutzen powders.

The BP substitute, Pyrodex, _claims_ to be low-smoke, but in fact makes as much white smoke as black powder does. Pyrodex is potassium perchlorate-based, and burns roughly at the same speed as black powder, with about the same explosive force, volume-for-volume (NOT weight-for- weight.) Pyrodex is MUCH less dense than BP, which is 1.7g/cc solid density, and about 1.0g/cc mass density in granulated form.

So... a 6-quart pressure cooker would hold as much as 12 pounds of Black powder. That would make quite a 'whack', suitably contained.

You'll also note that the containment failed before the lid fragmented. See the distorted lid pictures. The shrapnel injuries must've been the result of shards of the pot base, or the nail-shot additions to the load.

There are a couple of other mixtures, pyrotechnic in nature, that would give the same basic profile of fireball, smoke, and propulsive force.

One thing for sure... it was NOT "flash powder" (the stuff that kids so often try to collect from firecrackers to make bigger ones). Flash powder is so fast-burning under containment as to be categorized for storage and transportation as a high explosive (although it's not really). It also makes a small and compact, bright-white fireball.

LLoyd

No way! That's totally unfair.

Somebody's gotta pay for this.

Were you involved in the investigation of the Grucci fireworks plant that exploded on Long Island in the 1980's?

"ATP" fired this volley in news:51729395$0$19549$ snipped-for-privacy@cv.net:

No, although our company helped pick up some of their manufacturing load until the Gruccis finished re-building. We were in NJ, so close enough to lend a hand. (I'm no longer with that company)

The Grucci organization (Pyrotechnique by Grucci, Inc) is still one of my clients, although my prior employer no longer interacts with them.

LLoyd

I saw the battery brand (good one) that's used in RC stuff, I'd bet it was just simple kitchen-type timers probably set for the same time and were only ten or so seconds apart.

Tom Gardner fired this volley in news:CuSdnSoU8pwOCO_MnZ2dnUVZ snipped-for-privacy@giganews.com:

WHY would they use a PWM-controlled ESC with a kitchen timer? And why would they use a Novak RC receiver with a kitchen timer?

Nahh... look at the pictures!

Lloyd

Darwin? In retrospect, why didn't he mix it with water and use it as fertilizer. I'm not a smart guy but even I know better...EVERYBODY knows better! Was he not aware of how to handle powder?

I think they used my dogs' farts...quite deadly!