Each business page of a wall-mounted monthly calendar has glued to it, near the spine of the calendar, a thread of detonation cord. A small battery powered timer triggers the respective thread of det cord at the end of each month. The obsolete page gracefully falls to the ground.-- the porpoise, Oct 09 2014 Plus people who wind up with stacks of calendars that didn't sell could have fun with them (+)-- normzone, Oct 09 2014 // The obsolete page gracefully falls to the ground. //
… and is lost in the rubble of the wall it was attached to.
Either this is irony, or you have no actual practical experience with det cord, [porp]. To begin with, initiating it requires a primary explosive. A No. 8 electric det, if held in the hand, will result in instantaneous amputation of same at the wrist.
If you deploy detonators and det cord indoors, very quickly indoors becomes outdoors.
Anyway, [+].-- 8th of 7, Oct 09 2014 Hey I'm relying on you for explosive expertise. Maybe it's a really thin custom det cord and the wall might last till December.-- the porpoise, Oct 09 2014 You could use that surgical det-cord (it has another name so as not to alarm patients, but I don't remember it) which is used in certain situations to cut bones quickly. I believe it's electrically initiated.-- MaxwellBuchanan, Oct 09 2014 // surgical det-cord //
If there's even a remote possibility that this is a thing, I will be pretty surprised. I think you'd do less damage with an axe than you would det cord for amputation.
//If you deploy detonators and det cord indoors, very quickly indoors becomes outdoors//
Well surely it can be scaled down, [8th]? I know you'd run into problems of scale, and from what I remember you run into problems of sustaining a detonation over too small a cross section, but surely there are materials available which are more suited to narrower det cord, than say what is used at present?-- Custardguts, Oct 09 2014 Monocrystalline HMX has the superior propagation characteristics you want, but it's not suitable for a flexible item like det cord. Having said that, the calendar spine could be an array of rigid rods.
However, cross-coupling of the shock wave could cause all the rods to initiate almost simultaneously.
There are low-yield pyrotechnic compositions that might be the solution, and they only require ignition, not a detonator.-- 8th of 7, Oct 10 2014 Black powder, maybe?-- the porpoise, Oct 10 2014 // Black powder //
Not really. It's hygroscopic, and it produces a lot of hot particulates.
An extruded nitrocellulose derivative blended with an inert combustion modifier like glass fibre might be suitable.-- 8th of 7, Oct 10 2014 do you mean that synonymously with "monocrystalline" ?
Anyways, a "bang" is probably not feasible, but a very thin visco fuse should do it, for the cartoon, sparking fuse effect.-- FlyingToaster, Oct 10 2014 A tube of flash paper might be enough, if the risk of cross-linking to the other array elements can be controlled.-- 8th of 7, Oct 10 2014 for that you might as well use black powder and put some scotch tape over it. avoiding xlinking's easy: a strip of al foil on the back covering the perforation line, glued below it but not above.-- FlyingToaster, Oct 10 2014 Could you make the whole page out of flash paper and avoid the mess on the floor? To avoid cross- linking include some nitinol foil between pages. Maybe the heat from the burning flash paper could activate the nitinol so it rolls itself up into a little tube by the spine of the calendar.-- scad mientist, Oct 10 2014 random, halfbakery