From: Duke McMullan n5gax <ee5391aa%hydra.unm.edu%ariel.unm.edu@ssyx.ucsc.edu>
Subject: Howdy and how?
Date: 1 Mar 90 10:29:47 GMT


For openers, does anyone know how to get email to/from Compuserve? My motiva-
tion is that this account will shortly be assigned to someone else, and I'd
love to be able to continue on this and on the cavers' mailing lists.

I've been told that I could simply mail to myself as 70245,1145@compuserve,
but our mailer gags on the "compuserve" address. Perhaps someone knows the
internet node number (like 128.64.425.3, etc.)?

Now, on to pyro. Aluminium is a MARVELOUS reducing agent, as it releases an
enormous amount of heat. Classically, mix it with iron oxide to get thermite
(or thrmit) which burns ferociously and dumps out a stream of molten iron.

Other oxidizers work well: Potassium chlorate, potassium perchlorate, sulfur,
potassium permanganate, sodium peroxide, cupric (copper) oxide, and others.
Here are a few properties of the various mixes. This is off the top of my head,
so I won't give proportions here.

Potassium chlorate: One of the hottest, best, and least safe. Gives a bright,
white light, lotsa heat. Easy to ignite. May self-ignite. A small amount of
most acids (noteably sulfuric) will set these mixes off. Hence, mixing KClO(3)
with sulfur is considered hazardous practice. The result can easily ignite
spontaneously, since sulfur tends to form a little (very little, but enough)
sulfuric acid on extended contact with moist air. Still, the mix is quite
useful as an igniter, since it's shock- and friction-sensitive. If you mix
KClO(3) and S (and you should, to find out its properties), use VERY small
mixes. The stuff's damn sensitive. Don't EVER store these mixes. One other
caveat: Avoid, except in EXTREMELY small quantities, mixing KClO(3) with phos-
phorus in any form. The best description is "hypergolic".... Additionally,
KClO(3) forms a very heat-sensitive mix with common sugar (sucrose), and,
I THINK, with starch. I'll try starch later this week. It's very to ignite
with, say a peanut flashbulb (convenient squib!) and can be used as a primary
igniter to set off some of the more stubborn mixes.

Potassium perchlorate: Almost as good as KClO(3), and almost as good. The
KClO(4) is a great deal safer than KClO(3). These two mixes are the basis for
most flashcracker powder.

Sulfur: Reacts with the Al to form aluminum sulfide, and lots of heat. The 
fumes given off are rich in sulfur dioxide, so react these outside. The result-
ing slag is very interesting...drop the stuff (once cooled!) into water, and
hydrolysis goes along its merry way, giving off hydrogen sulfide. Instant rot-
ten eggs! The use of such things, of course, is best left to the individual :-)


Potassium permanganate: Not remarkable, compared to the (per)chlorates, but is
ignited by contact with various organic liquids. Glycerine is good; drip a lit-
tle on and step back....

Sodium peroxide: Works, but not spectacularly. Remarkable that water (in SMALL
quantities) will ignite it. This need not be deliberately applied water -- one
of my more embarassing experiences in high school involved a small pile of the
Al-Na(2)O(2) mix going off on its own from absorbed atmospheric moisture...and
New Mexico is NOT known for its high humidity! I suspect that a small amount of
sodium HYDROXIDE (anhydrous, of course) added to any of these aluminum mixes
would give it water-ignition properties. Methinks what happens is that the NaOH
(which results from reacting water with sodium peroxide) reacts with some of
the aluminum to form sodium aluminate and quite a bit of heat, which heat starts
the rest of the stuffs doing their thing.

Cupric Oxide: Not much of a flash, but it goes FAST. Another high school mis-
adventure resulted from this. I put an Al-CuO mix in a 2"x2" coin envelope,
inserted a copper wire etched thin at one point with nitric acid (the igniter),
and wrapped a lot of masking tape (the mistake) around the envelope. I placed
this on top of a glass bottle, expecting the bottle to shatter from the heat
of the reaction. I plugged the ends of the wire into 110VAC, and (*BOOM!*).
No damage done; it didn't even break the bottle. It sure scared the hell out of
me, though.

Classical thermite is aluminium mixed with ferric oxide. If chromic oxide is
used instead, instead of molten iron you get molten chromium. Chromic oxide
Cr(2)O(3) is green. There's also chromium trioxide (CrO(3); chromic acid;
chromic acid anhydride). I've never tried this, and the extremely hygroscopic
properties of the stuff worry me. If you try it, let us know.

Almost any sulfate salt: The SO(4)[--] group has one sulfer and four oxygens
to give up; they work well. Particularly remarkable is calcium sulfate. In
its anhydrous, finely divided form, it's known as plaster of Paris. That's
right, a castable incendiary! It's ferociously hot, and difficult to ignite.
The aluminum-sulfur mix is the recommended method. Experience shows us that a
Mappgas torch also works. ;^)

A friend advises me that mixing acetylene and oxygen from a welding rig in a
large plastic garbage bag (with fuse attached) sounds like dynamite when it
goes off. Sounds a little dangerous to me. The bag tends to develop static
electricity, and one little spark at the wrong time, and it's off to the hos-
pital to get your eardrums repaired. Don't laugh; that's happened before to
cavers playing around with carbide. Natural selection, I suppose....

That's enough for now; gotta save something for later letters...like two-
component ammonium nitrate explosives (including the astrolites), etc.


							BOOM!,
							   d