Another way of looking at things is to imagine if you were to put several ounces of black powder on the ground and light it - it would go "poof", although the burn time would be measurable, and very little pressure gradient would be observed. Repeat the test with the same amount of black powder contained within a sealed container, and now you have a relatively powerful pipe bomb.

The containment provided by the pipe in the second example results in a significant increase in internal pressure, which in turn is what allows the black powder to produce a relatively large explosion. Essentially as the black powder combusts (deflagration in this case) the combustion gases expand (subsonically) until they either rupture the container, or simply reside due to exhaustion of the reactants.

In the case of IronRaven's fire jar, I suspect that the wall thickness toward the end of the square nub is such that it would rupture first and essentially act as a pressure vent before the entire container would rupture and caused any damage or serious injuries. Having the match heads alternating as he does (most likely for increased storage capacity) also reduces the likelyhood of creating as much pressure rise if anything were to ever ignite the matches.

Jim

I don't think it will explode, but being gas tight-ish will snuff the fire before it burns up the other half of the matches and the all the tinder and sets of the lighter.

Actually, I alternate them because I"ve heard too many stories about people somehow igniting the heads of strike anywheres on the lid of their match safe. The poof and die in those cases, probably blew themselves out- this way, IF that should somehow happen, ok, some have singed butts, and others are tinder. *shrugs*

And yes, most likely the square end would turn into a rocket nozzle if this thing somehow had a catastrophic and spontaneous detonation. But odds are, the only way that will happen is if I fall off a cliff, or get stuck by lighting. Either way... I'm not sure I'll really care.

But yes, I do agree with the point that you and Mike raise about a containment vessel being a Bad Thing (TM) if it fails. That is why it is NOT carried next to my skin. I want stuff that will soak shrapnel between it and my spine. *laughs* Now, what I'd really like is something like a desicant pack that turns atmospheric O2 into a compound that is non flammible....

You aren't getting this open with heavy gloves without leverage, that nub is about an inch square and not quite that tall. But in terms of cold, it schedule 40 PVC. It's pretty tough stuff, but I don't trust anything, not even metal, not to break at -40 (same for both sides of 45N) after having destroyed a few alternators at -40. :P If cooled that far, and kept there for a while, a good sharp whack will probably crack it pretty easy, but that holds for most things...

My elder brother developed a childhood interest in rocketry, until he discovered that rocket engines with crimped nozzles are grenades, and blew up a neighbor's back porch. The sacrificial blow-out nib on the fire jar is sort of intriguing from a rocketry point of view. The blow-out feature is reminiscent of the DuPont gunpowder factory in Delaware. the factory buildings had 3 stone walls and one wooden wall, facing the river. When the inevitable explosions occurred, the wooden wall blew out and deposited the debris in the river. The DuPonts could then simply replace the blowout wall, roof, (and employees) and get back to work. Very practical folks. It is hard to believe that we have been talking about explosions for 2 days without a comment from Blast. Anyway, nice kit, nice concept,Raven-

Sorry, I've been busy.



A word of warning. PVC shrapnel doesn't show up on x-rays very well. They have to track it down by probing the entry point with very long needles.

Still, I'm thinking this might be a good experiment when I have the time.

-Blast

hey blast in ur profile pic, it looks like your holding a grenade! What is it? Avacodo maybe?

Blast, it's going to be about 8" behind my shoulder blades.... If it goes, I'm toast. *laughs*

Honestly, I think ya'll are jousting at windmills. It's literally an oversized match safe, and while those sometimes flare, I've never heard of one that wanted to be a grenade when it grew up.

I think it's an interesting idea, bulky as you already obviously know but interesting none the less.

As far as dangerous... not to sure. I did some experiments with the orange and green match cases. I filled them up, lit 1, stuck it in and closed it, the rest ignited and melted the lid and that was it. This proves that with little air (way less than yours) the match will continue to burn, ignite other matches they will burn and create tremendous heat.

Now, yours may technically be 'illegal' as you have an ignition source, and a flammable/explosive inside. Is this considered by law a pipe bomb? Possibly. It may be worth investigating as it would be terrible to get arrested and go to jail for such a thing, also would be even worse if it did go off and make a small pop (most likely) and bring attention to yourself or set something on fire/etc.

Personally I think there are better ways to store matches, a lighter and cotton.

Climberslacker,

Yep, it's an avacado. Good things, those avacodos. Nutrient and calorie rich, very tastey, and nicely compact. I always take one on my adventures.

-Blast