Roll cap detonator?

[Marmaloon]

Whilst reading a copy of 'The Science of Revolutionary Warfare', a friend of mine told me they espied a way to detonate (at least 19th century) dynamite. The method described was to obtain a 'pen top' and trim and pack in about 25 caps meant for a child's cap gun, then inserting the visco in there and using that to detonate the main charge of dynamite(?). In the interests of science, my friend obtained some roll caps, just the plain old variety that comes from China, some thin wall 1/4 inch inside diameter aluminum tube, some epoxy, some hobby fuse, a squinch of double base powder. They state they packed in about 250 - 300 caps carefully punched out and inserted into the bottom of the tube with a section of 3/16 dowel, the closed end of the tube was sealed with epoxy, then they put in the fuse and powder as there was about an inch of space left in the tube, sealed the fuse in with epoxy, and tried it out. From his account, the report was about equal to the report of the .30/30 rifle, and the tube was shredded.

[Chris The Great]

I'm not really surprised, after all they used black powder to detonate dynamite as well. Caps would need to be used in larger quantities, but I would think it would get the job done.

Also, modern 8 shot caps are a mix of potassium chlorate and red phosphorus. THAT will set off your dynamite, although it's fairly hard to get the stuff out since they are tiny and have sand in them.
It also looks like a greaty source of red P in a pinch though, as these are sold everywhere and you just squish them and drop in hot water to get the P out. Problem is you're going to spend maybe $20 for maybe a gram (haven't tried it yet). More on that when I try it out and see if it's valid, in a different thread as well, where it won't be off topic :p

[knowledgehungry]

I'm sure borrowing the caps would not be difficult.

[FragmentedSanity]

If you can find them, paper starter caps (used to start races and such) are a better source than toy caps. They contain a considerable ( for an OTC cap anyway) amount of explosive - which is accessable by simple peeling back the wax paper. I used to be able to buy them OTC for $5.00 per 100, but I havent tried it in a while. Of course schools and sporting clubs are also a useful source.
It dosent have the same appeal as blowing something up with a childs toy tho.
I'm also fairly sure Ive seen caps that contained mercury fulminate - which should work reasonbly well as a det.

[Ropik]

I've never seen any starter pistol made for oversized paper caps. All of them were made for small blank cartridges.
About similar method of detonating dynamite: In "Guerilla's arsenal" David Harber says: "The primer in large-calibre rifle cartridge is capable of initiating dynamite with at least 40% nitro with a fair degree of reliability", maybe even large blank cartridge with a plastic top would be a possibility. Tear off the plastic, insert the igniter and seal with wax. Off it go. See Guerilla's arsenal to see what I mean.

[Marmaloon]

I am not sure if the originator of this method, Mr. Johann Most, was aware that nitro glycerin based dynamite is succeptible to low order detonation. Maybe this is all he was getting when he tried this method out on his dynamite. It's pretty hard to say over 100 years after his book was written. By my calculations, 300 caps would contain about 35-40 grains of Armstrong's mixture, so that's approaching 3 grams, I have read some publications stating that 1.5 grams of picric acid boosted by a lesser amount of primary would be good enough to detonate RDX based explosives, but I am guessing armstrong's mixture is somewhat less powerful than picric acid, for example. This would be an interesting avenue of experimentation, to try the roll cap detonators out on various explosives to see if you get a high order detonation out of it. I don't have the means or the liscences to pursue this . . .

[SweNMFan]

I was in a toy story today and I found Cap refills for a toy shotgun.. 24 caps and 2 mini 12guage shells.. The shells is in two parts, a metal part with an anvil and a removable plastic part.. In the package it reads:

Contents of these caps is less that 0.20 grains per cap.
Composition: Potassium Chlorate, Magnesium Oxide, Red Phosphorus Synthetics glue fossil meal cork sawing

Edison Giocattoli is the manufacturer and here they cost around $3 to buy..


And they have a web at http://www.edisongiocattoli.it/


Just hot glue the "bottom" of the plastic part (as it have a hole thru it) , fill it with you favorite primary. Put BP in the metal part and a cap..

The plastic part have an ID of 9.1mm and when metal part is inserted the internal lenght is 29mm so there is around 1,8cm3 in it.. The metal part have an ED of 11mm :)


When I was younger I removed the mixture from 250-350 plastic caps and put it in a piece of pipe from a telescopic antenna on a radio and exploded it inside a 5L plastic military water flask (that have fairly thick walls). The bang was way louder than I was expecting and shrapnel pierced the bottle and embedded it self in the plaster wall.. And yes I did it indoors.. That thing could have ripped my fingers off..

[bcc1985s12]

Also, modern 8 shot caps are a mix of potassium chlorate and red phosphorus. THAT will set off your dynamite, although it's fairly hard to get the stuff out since they are tiny and have sand in them.


When you state that caps would need to be used in larger quantities than bp to detonate the dynamite, I am not sure you understand the power of the child's toy caps. Empty the powder from about 70 caps(the type that come in red plastic 8-shot rings).

This cost's about 69 cents around my house. This is relatively simple and quick once you get the hang of it.

Put the powder in a gell cap(a vitamin capsule, like for activated charcoal), with a small ball-bearing on one or both ends, inside the capsule as well. If you do not have ball-bearings, you can use BB's, or even small stones. Tape it clased, and throw it, it will make a loud bang.

It looks like this, cap powder in the center, and tape holding the two sides of the capsule together.

(O:::::O)

An equal amount of homemade black powder or even store-bought reload cannot make a bang sound so loosely confined, in such small quantities. Cap powder is powerful, and could undoubtedly be incredibly useful in homemade detonators. I will attempt one such detonator and post the results.

++++++

Don't quote entire posts, only the relevant portion.

NBK

[Chris The Great]

Roll caps, which I refered to in the first sentence, do not use the potassium chlorate/red phosphorus mixture which is in the 8 shot caps. AFAIK roll caps are blackpowder and some other stuff to make it impact sensitive. It is not as powerful as the 8shot cap mixture, which I did recommend as an improvished primar mixture (although you would need a much larger quantity than if you just used some primary HE).

[Bert]

Roll caps will generally contain Potassium chlorate and Antimony sulfide, perhaps with some Sulfur and a carbonate. You may wish to explore the use of the friction ignition tips of strike anywhere matches... Cheaper and easier to harvest than the 8 shot caps.

If you really want to live dangerously, Boomer described a method of separating the Silver fulminate from the gravel in throw down snaps. Me, I'd be way too scared to handle any of these things dry in the necessary amounts. Not worth a finger for an experimental blasting cap-

[Marmaloon]

Roll Caps made of black powder and sand? Interesting, that's the first time I've heard of that. . .

[nbk2000]

BP and sand? How the hell would that work? BP is virtually immune to crush initiation, and sand isn't going to spark.

Whereas, KClO3 looks like sand granules, and antimony sulfide is black/grey, so maybe that's what you're seeing.

[Marmaloon]

Does anyone know the link for the Journal of Pyrotechny? There is a feature article in one of their recent journals about what has been discovered about roll caps. At least I think it's the Journal of Pyrotechny, published in the States'. You all have a fine weekend. Pray for the people overseas.

[Marmaloon]

http://www.jpyro.com/journal/issue_21/index.htm#Mniszewski21

There you have it lads, all laid out for you. Been dragging my butt about ordering a copy.

[dana_m_h]

When I was younger I took one whole roll of caps and hit it with a hammer .... the percussion was immense... the hammer flipped out of my hand and I couldnt hear right for 3 days. These have way more power than we give credit to. If you were to disassemble several of the boxes you would have something very powerful indeed.

[Cobalt.45]

In the link Marmaloon provided above, one article states that yields approaching 80% of that of TNT were achieved. Obviously, a very large amount of caps.

Would this point to a composition more akin to a type of flash or more likely as mentioned before, primer comp? Seems like an awfully big yield, from just caps...

Who was it that said, "There are three kinds of lies; lies, damn lies, and statistics"? You can get numbers to do your bidding, often.

BTW, thanks for that link, Marmaloon. Tons of good links contained on their homepage.

[FullMetalJacket]

In the "Cia Guide to Improvised Sabotage" They reccomend a method of (slightly) remote detonation by threading a length of detcord into a blank or de-bulleted cartridge and firing it from a rifle.

I used to use these little roll-caps as an impact ignition source though.

[texaspete]

In the "Cia Guide to Improvised Sabotage" They reccomend a method of (slightly) remote detonation by threading a length of detcord into a blank or de-bulleted cartridge and firing it from a rifle.


Wouldn't the hypersonic shockwave destroy the rifle? (assuming its PETN detcord)

+++++++++

Yes, it does. It's a one-time way of doing it, so you use the shittest rifle your band of merry men have. :)

NBK

[Marmaloon]

Just got my Journal in the mail, to paraphrase, what they did was take a small tube filled with flash mix, initiator was an electric match, tube was just the right size to fit snugly in the concavity formed by 3 rolls of caps. 80percent TNT equivalency was reached with a full case of 1200 rolls, the event was not completely understood, although sympathetic detonation was suspected as the cause. A secondary effect was observed most probably due to the pulverized paper component of the caps burning away. They initially tried using an initiator composed of stacked caps, but this failed to propagate the detonation. This makes sense as the explosive content is not 100 percent with that type of arrangement. the Cap they did have some success with was about 3 inches long, 1/4 id, 70/30 mix.The flash mix 'fusee' they used was about 1/2 tnt equivalency by itself.
What prompted the research was an unfortunate accident somewhere in the world recently where 2 employees of a toy factory were killed when they were operating a bubble packaging machine set up for wrapping roll caps.

[Marmaloon]

Another bit of their research has revealed that on average, their computations revealed that each cap contains on average 1.85 milligrams of cap mixture, which seems like an impossibly small amount, so you'll excuse me for miscalculating the actual amount in the caps I calculated previously. They came to this figure by cutting circles with a paper punch between the dots, getting a large given amount, and then punching out the dots, same given amount.

[Diabolique]

Marmaloon, I believe it was Alfred Nobel who first used BP filled detonators to initiate dynamite. As for sand in the caps, I was told that it is to increase friction when the cap was struck, helping set off the BP fines.

It may be better to use commercial or well made expedient BP - no sand. Carefully crush the grains a few at a time - inevitably, some will go off.

I understand that BP squibs have been used to initiate flake TNT. I wonder if flake TNT can be used to initiate PETN?

[Marmaloon]

It would seem that going with high powered flash powder would be preferrable to the roll caps.