Boston Bomb triggered by cell phone?

Speculation is that the bombs were set off by cell phone. I wonder if a cell signal would penetrate the metal of a pressure cooker. Mine
barely works in my metal shop building; with the doors open. Any experts want to weigh in?
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snipped-for-privacy@aol.com wrote:

The pictures I have looked at of the various parts looked like all common discrete components not cell phone pieces. The battery looks like a common RC car pack. Then a cheap alarm clock for a timer/trigger. Nails from any hardware/building supply place. The ball bearings are probably slingshot ammo.
--
Steve W.

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The active part would be on top of the pot with the electronic explosion cap through the regulator on top. So when the unit blew the cap exploded by itself and the stuff on top would be flung all over the place. The battery was heavy enough not to go far.
I suspect two numbers - speed calls - and away they went. Likely each of the two perks did one each - in case one was caught hot handed.
Martin
On 4/18/2013 1:54 AM, Steve W. wrote:

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On Thu, 18 Apr 2013 00:01:27 -0500, snipped-for-privacy@aol.com wrote:

one could simply run a small insulated wire through a matching hole in the body of the pot for an antenna. Its not rocket science and a small hole wouldnt effect the pressure build up significantly.
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wrote:

I thought it was on the news that cell phone service was turned off in Boston for the run...to prevent just this!
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Cells were turned off just after the first explosion. The runners and their watchers all use cells. Runner at end and watchers to each other along the race.
Martin
On 4/18/2013 12:07 PM, Tom Gardner wrote:

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I don't know if you recognize any of the common parts shown in the photos of the debris, but there were:
1) parts of a standard 7.2V NiCd 'hobby' style battery pack for models (cars and planes) 2) parts of an electronic speed controller for RC cars or planes... looked like a Great Planes or Novak component (in-line style) ESC. 3 parts of a Novak RC radio receiver for cars or planes (orange case, very recognizable)
I'll let you guess from that whether or not cell phones were used as the firing box. I'm guessin' your guessin' won't be swayed by this.
(I'm in an explosives-related biz, so ways to ignite things are reasonably familiar to me)
Lloyd
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On 4/18/2013 8:31 PM, Lloyd E. Sponenburgh wrote:

It must be nice to have a fun job!
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On Thu, 18 Apr 2013 20:31:47 -0500, "Lloyd E. Sponenburgh"

RC controlled blaster? Fascinating! Command detonated then.
What was the speed controller used for? The trigger pulse to the ignitor, whatever that was? Nichrome wire/model rocket type ignitor across the output?
I wonder why there was a 15 second delay between blasts? Channel change?
So how far away from the two blasts could the command unit have been?
Gunner
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On Apr 18, 9:31pm, "Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote: > (I'm in an explosives-related biz, so ways to ignite things are

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
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On Sat, 20 Apr 2013 05:07:49 -0700 (PDT), " snipped-for-privacy@krl.org"

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.
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On 4/20/2013 8:55 AM, Gunner Asch wrote:

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?
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Black powder doesn't go "skunky", nitrocellulose-based propellants do.
BP contains potassium nitrate and sulfur; both good soil amendments. NC powders make lousy fertilizer, releasing most of their decomposition products as nitrous oxides and concentrated acids.
LLoyd
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On 4/20/2013 9:38 AM, Lloyd E. Sponenburgh wrote:

I' ll be damned! The NRA reloading manuals that I use for teaching classes state that both single-base and double-based powders can be used as fertilizer to destroy it. I won't teach that anymore!
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used

Tom, sun (UV), moisture, and bacteria will decompose both single-based and double-based powders. Both nitrocelluose and nitroglycerine will decompose under those conditions, as will nitroguanadine -- the 'triple- based' third component.
They just make lousy fertilizer, tending to significantly lower the soil pH to levels dangerous for many plants. 'Might work on gardinias or camillias...
LLoyd
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On 4/21/2013 9:21 AM, Lloyd E. Sponenburgh wrote:

At least I, or anybody I know has had powder to destroy. It will last forever (almost) if kept sealed and cool. For it to go skunky would mean improper storage or it's VERY old. I go through it too fast to worry about it, but I never have too much laying around, I've only got about 9 lbs in the cabinet. When I DO have a good quantity, I tend to burn it faster.
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Shrug..brain fart. Guy was my mentor and reloading instructor when I first got started.
I guess he thought it was "fun and safe" to burn off the old powder. But...a big cloud of Bullseye was outside of his experience.
RIP Joe Moran.
Gunner
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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
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"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message

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