# Blowing Up Dynomite Like They Do in the Movies: Pushing a Plunger in a Big Box **URL:** \ **Category:** Factual Questions\ **Created:** [January 12, 2005, 11:15pm UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459 "2005-01-12T23:15:49Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![lawoot](https://avatars.discourse-cdn.com/v4/letter/l/35a633/32.png) [@lawoot](https://boards.straightdope.com/u/lawoot)\ **Post date:** [January 13, 2005, 5:04pm UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/21 "2005-01-13T17:04:01Z")
> [@mks57](#): > > Checking fuse speed? I read something once that stressed the importance of actually testing fuse speed, since it was too easy to accidentally use a fast burning fuse instead of a slow burning fuse. _from_ The Producers\* (1968)\*, via the IMDb quotes page: > [@](#): > > Franz Liebkind: Gentlemen. Ve have here a technical problem. Hmm? I do not know if vat ve have here is ze quick fuse or ze slow fuse. Ja, ja, I must find zis out. > [snips dynamite fuse] > Franz Liebkind: Zis is critical. > [lights fuse with match] > Franz Liebkind: Ha ha ha, ja ja, you see zis? You see zis here vat I have told you? Yeah, zis is an example of smartness here. I have said that zis is ze quick fuse. Huh? And zis IS ze quick fuse. > [pause] > All: THE QUICK FUSE! > [explosion] ---
**Author:** ![lawoot](https://avatars.discourse-cdn.com/v4/letter/l/35a633/32.png) [@lawoot](https://boards.straightdope.com/u/lawoot)\ **Post date:** [January 13, 2005, 5:09pm UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/22 "2005-01-13T17:09:07Z")
> [@mks57](#): > > Checking fuse speed? I read something once that stressed the importance of actually testing fuse speed, since it was too easy to accidentally use a fast burning fuse instead of a slow burning fuse. _from_ The Producers\* (1968)\*, via the IMDb quotes page: > [@](#): > > Franz Liebkind: Gentlemen. Ve have here a technical problem. Hmm? I do not know if vat ve have here is ze quick fuse or ze slow fuse. Ja, ja, I must find zis out. > [snips dynamite fuse] > Franz Liebkind: Zis is critical. > [lights fuse with match] > Franz Liebkind: Ha ha ha, ja ja, you see zis? You see zis here vat I have told you? Yeah, zis is an example of smartness here. I have said that zis is ze quick fuse. Huh? And zis IS ze quick fuse. > [pause] > All: THE QUICK FUSE! > [explosion] ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [January 13, 2005, 5:56pm UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/23 "2005-01-13T17:56:40Z")
> [@spingears](#): > > Mine Safety and Health Administration has approved two new hand held devices… > > [\*\* I-Kon and Electronic Detonator Systems \*\*](http://rockproducts.com/mag/rock_msha_approves_electronic_2/) The Daveytronic? Sheesh. No offense to (assuming) Mr. Davey, but you couldn’t pick a more manly name like Blastmaster Ten Thousand? It certainly makes the surveyor’s [dumpy](http://www.tpub.com/content/construction/14043/css/14043_136.htm) level sound good. Reading that article, I get the impression that the caps / initiators all have unique digitally-coded IDs so they can tell which one out of however many dozen on a shot has become disconnected? Pretty slick, even if it takes longer in the setup to key in “cap #568BE2300C2 is in hole #4” OTOH, unique IDs will make it easy to track the devices in case they get uhh… diverted and the authorities want to know where they were stolen or “lost” from. One thing I’ve always wondered about is how the det cord and similar “non-el” systems work. I understand twisting wires together. I’m fuzzy on how det cord is connected - I’ve seen jobs where the stuff is branched off to multiple locations - is it just taped side by side and the shockwave is picked up by the adjoining strands, or is there a “splice” or “repeater” cap in the bundle? ---
**Author:** ![RogueRacer](https://avatars.discourse-cdn.com/v4/letter/r/7ab992/32.png) [@RogueRacer](https://boards.straightdope.com/u/RogueRacer)\ **Post date:** [January 13, 2005, 7:57pm UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/24 "2005-01-13T19:57:46Z")
> [@gotpasswords](#): > > One thing I’ve always wondered about is how the det cord and similar “non-el” systems work. I understand twisting wires together. I’m fuzzy on how det cord is connected - I’ve seen jobs where the stuff is branched off to multiple locations - is it just taped side by side and the shockwave is picked up by the adjoining strands, or is there a “splice” or “repeater” cap in the bundle? Knots. Det cord is fun stuff. 🙂 Re: TNT and cap sensitivity. Perhaps military TNT is not real TNT (I don’t remember), but it is most certainly “cap sensitive”. ---
**Author:** ![Blown\_Injected](https://avatars.discourse-cdn.com/v4/letter/b/a87d85/32.png) [@Blown\_Injected](https://boards.straightdope.com/u/Blown_Injected)\ **Post date:** [January 14, 2005, 1:47am UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/25 "2005-01-14T01:47:34Z")
> [@gotpasswords](#): > > One thing I’ve always wondered about is how the det cord and similar “non-el” systems work. I understand twisting wires together. I’m fuzzy on how det cord is connected - I’ve seen jobs where the stuff is branched off to multiple locations - is it just taped side by side and the shockwave is picked up by the adjoining strands, or is there a “splice” or “repeater” cap in the bundle? Just put a lump of C4 or lump some other piece of plastic around the intersection of the cord or linear flex or whatever is branching off/connecting to other stuff to ensure continuity. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [January 14, 2005, 1:48am UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/26 "2005-01-14T01:48:02Z")
> [@Trailer Park Casanova](#): > > The best example of this is in the movie: Bridge on the River Kwai, where Alex Gueiness gets shot and falls on one. > In the movie they describe the plunger merely makes contact at the end of the stroke. > But that’s Hollywood balderdash,: like navigating the Fla Keys in a boat with a gas station map. That would depend, I’d wager, on the gas station. The one’s around here on the delta have charts. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [January 14, 2005, 2:22am UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/27 "2005-01-14T02:22:00Z")
Some Halon\* tank release mechanisms use a small electrical explosive device, called a _squib_, to burst a disk and release the gas. I’ve also heard caps called squibs. \*An obsolete fire supression gas. ---
**Author:** ![Blown\_Injected](https://avatars.discourse-cdn.com/v4/letter/b/a87d85/32.png) [@Blown\_Injected](https://boards.straightdope.com/u/Blown_Injected)\ **Post date:** [January 14, 2005, 2:48am UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/28 "2005-01-14T02:48:37Z")
> [@gotpasswords](#): > > One thing I’ve always wondered about is how the det cord and similar “non-el” systems work. I understand twisting wires together. I’m fuzzy on how det cord is connected - I’ve seen jobs where the stuff is branched off to multiple locations - is it just taped side by side and the shockwave is picked up by the adjoining strands, or is there a “splice” or “repeater” cap in the bundle? Just put a lump of C4 or lump some other piece of plastic around the intersection of the cord or linear flex or whatever is branching off/connecting to other stuff to ensure continuity. ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [January 14, 2005, 8:15am UTC](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459/29 "2005-01-14T08:15:52Z")
> [@RogueRacer](#): > > Re: TNT and cap sensitivity. Perhaps military TNT is not real TNT (I don’t remember), but it is most certainly “cap sensitive”. The operative word was _cast_. Melt pure TNT and cast it, and the resulting block is not cap sensitive. You can make it cap sensitive by incorporating a small proportion of powdered PETN or RDX into it. Powdered TNT on the other hand _is_ cap sensitive! A certain level of empty space or “void volume” within the body of the explosive allows the detonation wave to release more energy within the material as it passes. This has led to the use of hollow glass microspheres additions as an alternative sensitiser for TNT, which I think is pretty neat. [Previous page](https://boards.straightdope.com/t/blowing-up-dynomite-like-they-do-in-the-movies-pushing-a-plunger-in-a-big-box/284459.md?page=1)