Comment by stevespang | Hacker News Reader

Comment by stevespang | Hacker News Reader

Erythritol tetranitrate (ETN) - - cousin of PETN, for which the detonation velocity of ETN is just above 8,000 meters per second - - while PETN det vel is about 8,300 meters per second plus, which is in the top 90% of highest velocity detonation velocities available from high explosives.

ETN is about 3 times more sensitive than PETN and is more sensitive to friction than the former mentioned compound. The decomposition of ETN is oxygen positive: C4H6N4O12 → 4 CO2 + 3 H2O + N2 + 3/2 O.

Why would any professional mess around with something that is 3x more sensitive than PETN ? Easier synthesis perhaps, but life changing or ending, if it detonates accidentally

PETN is the preferred explosive in the widely used "det cord", likely for a good reason, at 3x less sensitive.

You still need an initiator to set off PETN. He was making a primary explosive, which is needed to make an initiator or blasting cap.

Primary explosives are, as a rule, (and to perform their function) easy to set off, typically with heat or minor impact alone.

PETN just burns if you set it on fire. ETN detonates, which is what you want when you are building an electric initiator.

Making primary explosives is always sketchy business, since a spark or minor impact is often enough to set them off.

from what I understand this is the mystery of the Alfred P Murrah building bombing. There was never any conclusion as to how the torpex acting as the primary explosive was obtained.

I seem to recall reading that McVeigh broke into the storage magazine(s) at some local rock quarry and stole dynamite and blasting caps, which would be plenty to set off his home made ANFO (actually ANNM IIRC, but I digress). Guess I'll have to do some research to confirm my memories.

According to WikipediA, it was Torvex not Torpex.

I would actually expect professionals to come close to these kind of things more regularly. Seems like he left his guard down a little bit after working for years on these things.

and here we are complaining about bringing down production...

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