# How much high explosive is needed for the average car bomb?

**URL:** <https://boards.straightdope.com/t/how-much-high-explosive-is-needed-for-the-average-car-bomb/271091>\
**Category:** Factual Questions\
**Created:** [October 25, 2004, 7:01pm UTC](https://boards.straightdope.com/t/how-much-high-explosive-is-needed-for-the-average-car-bomb/271091 "2004-10-25T19:01:36Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [October 26, 2004, 5:07pm UTC](https://boards.straightdope.com/t/how-much-high-explosive-is-needed-for-the-average-car-bomb/271091/21 "2004-10-26T17:07:45Z")

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> [@Billdo](#):
>
> Is there any quantative way to compare the relative “bang” of military HMX and RDX explosives, a fuel-fertilizer bomb, gasoline, and other explosives?

There are several factors involved in a comparison, the rate of the reaction, the amount of heat (joules) and the amount of gas produced per gram of explosive. The relative importance of these factors depends on what the explosive is being used for. SimonX linked to a nice site that discusses the relative [power of explosives](http://www.fas.org/man/dod-101/navy/docs/es310/chemstry/chemstry.htm) over in the [GD thread](http://boards.straightdope.com/sdmb/showthread.php?t=282764&page=3&pp=30). The product of the heat given off, and the amount of gas given off is sometimes used to define a ‘power index’ for explosives, but it doesn’t really encapsulate all the factors involved in comparing different compounds.

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**Author:** ![xash](https://avatars.discourse-cdn.com/v4/letter/x/c6cbf5/32.png) [@xash](https://boards.straightdope.com/u/xash)\
**Post date:** [October 26, 2004, 6:35pm UTC](https://boards.straightdope.com/t/how-much-high-explosive-is-needed-for-the-average-car-bomb/271091/22 "2004-10-26T18:35:27Z")

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Considering the nature of this question, please post responsibly. Any details on techniques to build, etc. will result in a lock down.

Just a pre-emptive note.

Thank you.

- **xash**  
General Questions Moderator

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**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\
**Post date:** [October 26, 2004, 8:03pm UTC](https://boards.straightdope.com/t/how-much-high-explosive-is-needed-for-the-average-car-bomb/271091/23 "2004-10-26T20:03:58Z")

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> [@Billdo](#):
>
> Is there any quantative way to compare the relative “bang” of military HMX and RDX explosives, a fuel-fertilizer bomb, gasoline, and other explosives?

Comparing some data, for the same amount of “bang”: 12K# of ANFO = 10K# of TNT = 6.67K# of RDX. That said, the velocity of the detonation varies and is a significant factor. ANFO has a detonation rate of 3300 meters/second, TNT = 6900 m/s, RDX = 8500 m/s.

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