Post by Fred AbseIn the 19th, and early 20th centuries, men wore collars made out of the
stuff (Celluloid). Picture the scene; man wearing celluloid collar leans
over gas light jet, to light a cigar. POOF!
Photographers would occasionally use a celluloid collar when they ran out
of flash powder.
Never heard that before, but perhaps plausible given the process control
of the day?
Post by Fred AbseAKA guncotton. Evil stuff. Naval guns used it as a propellant, before
Cordite was invented.
Well, all production hand guns do, too.
I'd hardly call it evil stuff. It burns, yes, but it's no nitroglycerin.
Cordite it would seem has been *long* out of use, with "triple base" types
being preferred now.
http://en.wikipedia.org/wiki/Cordite
The term is British; though largely similar formulations have been in use
since their invention, I don't know that it was ever called Cordite in the
US.
Post by Fred AbseBeware antique knives and forks. Cellulose nitrate was used as a
substitute for ivory in handles (Trade name Xylonite). Piano keys, too.
Now outlawed in just about every jurisdiction.
Ping-pong balls too, e.g.
http://www.liveleak.com/view?i=b1c_1354489655
Sounds like the guys are German, so I doubt those at least are really
"outlawed in just about every jurisdiction".
Heh... with all the hubbub about plasticizers these days, one can only
imagine what they'd think of that sort of stuff now... Who cares about
plasticizers, my plasticware is giving me a headache! (Organic nitrates
are notoriously strong vasodilators, hence, for example, pounding
headaches after working near (let alone with) nitroglycerin and such.)
Post by Fred AbseEarly movies were made on nitrate stock. Now dangerously unstable.
Projection box fires were common, once. Once burning, it's next to
impossible to extinguish. Movie houses burned down.
The difference is, the gun stuff has a high nitrate content, the ping-pong
ball stuff has low nitrate content. It burns slowly. Probably not slowly
enough to extinguish short of an intense frigid CO2 blast, but it will
just about never explode.
Could be the old production stuff wasn't very well controlled, so the
minimum nitrate content wasn't as low as would really be desired for
safety. I don't know the intricacies of production like that.
Even the stuff they put in guns doesn't explode. Even when mixed with a
rather considerable fraction of nitroglycerin (e.g., Bullseye Smokeless at
up to 40%). Burns *very quickly*, ah, yep...
Offhand I don't know what the drop test of the latter is. It will
detonate at some point... just about every exothermic mixture does, from
the fairly inert but notable TNT, to innocuous thermite blends*. I wonder
how it compares to the others (like TNT, pure high-nitro NC, low-nitro,
and the old fashioned black powder).
*While I'm drifting off topic here, it's amusing how powerful some
thermite mixtures actually are. You can take a torch to some copper wire,
heat it until black, scrape off the oxide, then file some aluminum into
the pile of oxide. Place the mixture on a heavy steel plate, and tap it
with a hammer. But do cover your ears first! Somewhat larger, and better
mixed, compositions are used in 'exploding targets' for target practice.
Note the distinctive color of finely divided copper:
I don't recall that traditional (iron) thermite is ever explosive (well,
when dry.. moisture, that's cheating), but that might simply mean you
aren't trying hard enough.
Tim
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Seven Transistor Labs
Electrical Engineering Consultation
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