Reality check on bombs without oxidizers

[pinkpops]

To be sure, a "bomb" such as the ones in London, consisting of gasoline and propane, could make a pretty big fire, but don't explosives really have to have a handy source of oxygen? I'm not trying to tell anybody how to make a bomb or anything.

[RC]

1. You expect our terrorist leaders in the White House to think of everything?

They have other things on their minds to ya know.

[Solon]

2. Depends on the explosive...

Some require more oxygen than others, usually the surrounding air, if the bomb isn't sealed airtight, is enough to create an explosion. Gasoline and Propane, if not in a sealed container, will explode in the right circumstances, using just the air as an oxidizer. You can demonstrate this yourself, get a plastic gas container, set up a remote ignition sourced, only put enough gasoline in to spread across the bottom of the container, then put the igniter above this, and wait ten minutes, then hit the switch/button to activate the igniter. Its more than a small fire, I'll tell you that.

[pinkpops]

4. you sound experienced. I saw something like that when I was in the 5th

grade. A friend eith a match and a a gas can. It went WHOOOMP and singed his eyebrows. Still, the device described in the news was very fuel-rich, and would have to be in a very large container to be scaled up to the one you describe.

[dairydog91]

3. Depends...

On what you're detonating. In the case of a container of something that needs oxygen to detonate, just leave that container half-empty.

[Gold Metal Flake]

5. Liquid gasoline does not burn. Gasoline vapor burns.

To demonstrate, as a youngster, I used to wow my friends by throwing a lit match into a bowl of gasoline. The match hit and was extinguished. Now, take that bowl, throw it in the air over a fan and a lit match and you will have a nice fireball.

In an engine, liquid gas will cause incomplete ignition resulting in black smoke. Getting gasoline to finely atomize is an issue in your ordinary passenger car with EFI as well as by 500+hp big block Ford-powered hot rod with a Holley 850 carb.

The stuff in that car was not a high-explosive like the oil and fertilizer bomb used at OK City. Propane tank explosions (I have been involved in such) would cause damage, but not like a real ME-style car bomb, and the gasoline would not add to it until the container it was in was ruptured and the contents vaporised by heat.

This was some sort of amateur job. Fortunately.

[pinkpops]

6. my take as well.

[Coexist]

7. looks like a response from Mr. Johnson on the ? of his incorrect level of fear:

FROM LARRY JOHNSON:
Nothing explodes and yet it is something? What alternate universe are you inhabiting? Unlike you, I've seen propane tanks blow. They make a really loud noise. But you need a pretty big fire or high explosive to get them to detonate. Neither present in this case. Yet, let's use the fear factor to hype terror. Makes for good politics

[pinkpops]

8. I think they would have just melted in the fire

[Coexist]

10. thanks for the reponse

sorry, I edited my post, because I wasn't sure it made sense.

[Squatch]

9. Oxidizer = model rocketry

Bomb making = fuel + ambient oxygen + tamping + ignition

Try this sometime: take a block of C-4 explosive (fuel), set it on your concrete patio (ambient oxygen), and light it on fire with a cigarette lighter (ignition)

The result? Just a massively hot flame

Take that same setup (fuel, ambient oxygen, ignition), and lay a couple sandbags on top of it.

The result? No more concrete patio.

The sandbags provide tamping, which delay the expansion of gas.

You don't need C-4 to create the same effect. A controlled combustion of fuel in a small area creates a large explosion (think a modern rifle cartridge)

[pinkpops]

11. Are you saying C4 uses ambient oxygen?

[Squatch]

13. No, you have to import it from someplace.

The best oxygen comes from a 1/4 square mile area in northern Tibet.

:sarcasm:

Kidding aside, yes...C-4 uses ambient oxygen (including the oxygen IN the explosive itself) (C3H6N6O6)

[pinkpops]

14. I think the word ambient would exclude that which

is in the explosive itself.

[Squatch]

15. Take it from somebody who does this stuff for a living

The amount of ANY oxygen, ambient or otherwise, in the explosive train is the least of your worries, and usually not a factor. You primary concern is applying more than enough explosive material to the target to achieve the desired effects.

Insurgents in Iraq (and their counterparts in the UK, apparently) have gotten very adept at taking common flammable things and making big bombs out of them using commonly-acquired components. It's exceedingly simple to make a devastating bomb with any desired structure or personnel-defeating effects.

In this case, a propane tank wrapped with 16d nails will make for one hell of a large claymore mine.

[Swede]

12. Propane blows up real good on YouTube.

http://www.youtube.com/results?search_query=propane+bomb