From: Don <firstname.lastname@example.org>
Subject: still OT, acetylene tanks and such.
Date: Sat, 09 Dec 2000 00:26:47 GMT
OK...so no one who has replied seems to know what I was talking about so
I'll explain a little more.
Your acetylene tank is not filled with compressed gaseous or liquid
acetylene at 300 PSI. Gaseous acetylene is highly unstable (read
explosive) above 15 PSI. What is inside your tank is a blanket of fiber
soaked with liquid acetone with the acetylene in solution.
When your tank is empty they weigh the tank to make sure none of the
acetone has leaked (or been leached from excessive demand) out. The
correct weight should be stamped on every tank. If it is light they fill
it to the correct weight with more acetone. Then they fill it with
acetylene which goes into solution and is held by the acetone. When you
open the valve the lower pressures release the acetylene from solution
so it can be used. If there is ever a pocket of gaseous acetone in the
tank there is a very good chance of an explosion. There is no need for
oxygen or an ignition source inside the tank. The instability of the
acetylene itself will cause the explosion.
Pockets can occur if the tank is dropped...you may not see a dent
because the pressure inside may have already forced the dent back out,
but the fiber filling may have been moved away from the inside of the
Another way for an pocket to occur is if the acetone is low. If you
are using the acetlyene for a large demand application, the acetylene
may not be able to come out of solution fast enough for the demand. This
will make your work difficult and/or allow acetone to leave through the
hose. If you are using a large demand application you can hook up
several tanks to a header to draw off of so more than one tank can
supply the larger demand. If the tank is laid on it's side the liquid
level will be over the neck/valve stem level and the acetone can flow
out through the hose.
If the person doing the filling is not weighing the tanks he is
doing it wrong. This is mostly a problem when individuals own a big set
of tanks and have a smaller portable tank set. Rather than bring the
small tank to the dealer to be filled, they fill it themselves from the
larger tank without checking the weight. This is an explosion waiting to
happen. If you are using the acetlyene for a large demand application,
the acetylene may not be able to come out of solution fast enough for
the demand. This will make your work difficult and/or allow acetone to
leave through the hose. If you are using a large demand application you
can hook up several tanks to a header to draw off of so more than one
tank can supply the larger demand. If the tank is laid on it's side the
liquid level will be over the neck/valve stem level and the acetone can
flow out through the hose.
I'm not telling you not to fill your own tanks, but if it were me I
would take it to the dealer at least part of the time to be weighed.
Turn your valves off when not in use, this will save you money on
refills and may prevent a fire/explosion from pooled gas.
One final point.....
Check to see if your acetylene AND oxygen tanks have check valves on
them. When a tank is nearly empty there is a chance for the gas from one
tank to leak into the other tank. I wouldn't care to be nearby when the
acetylene tank that is down to 25 PSI has pure oxygen flowing into it
from the OX regulator set to 35 PSI. Wouldn't that make a nice BOOM. I
believe newer regulators are built with the check valves in but maybe
Sometimes I am glad that our workplace had all those damned safety
meetings. (former employee of Cleveland Cliffs Iron Co. 1975-1991;
Tilden Mine and Empire Mine; Marquette County, Michigan) 16 1/2 years
freezing and sweating my tail off without a lost time accident, although
I did pull muscles in my back a couple of times and received small 3rd
degree burns (hard to avoid when red hot pellets are falling around you
while you are working, although most everyone learned to walk with their
hands up at chest level so the pellets wouldn't fall inside your
From: John De Armond
Subject: Re: still OT, acetylene tanks and such.
Date: Fri, 08 Dec 2000 20:11:42 -0500
> When your tank is empty they weigh the tank to make sure none of the
> acetone has leaked (or been leached from excessive demand) out. The
> correct weight should be stamped on every tank. If it is light they fill
> it to the correct weight with more acetone. Then they fill it with
> acetylene which goes into solution and is held by the acetone. When you
> open the valve the lower pressures release the acetylene from solution
> so it can be used. If there is ever a pocket of gaseous acetone in the
> tank there is a very good chance of an explosion. There is no need for
> oxygen or an ignition source inside the tank. The instability of the
> acetylene itself will cause the explosion.
Hey, Don, excellent discussion of Acetylene. I want to correct one
minor part. I used to own an Air Products distributorship and was
treated by said company to a trip to one of their acetylene fill
stations and a class on same.
As far as I know, no welding gas vendor cascade fills cylinders in
the field. At least with Air Products, ALL cylinders, even the
little J ones, are sent to a filling facility. They told us that
there are only 3 fill stations in the US but I can't recall if that
was just Air Products or for everyone.
Anyway, the cylinders are received and weighed and acetone is added
as needed as you noted. The cylinder is then laid horizontally on
rollers and attached to an acetylene header via a hose and swivel
joint. The cylinder is then slowly rotated for about 2 days while
acetylene is supplied at around 200 psi. It takes that long to
saturate the matt/acetone matrix. The volume delivered to the
cylinder in SCF is measured and magic markered on the cylinder. A
nominal 150 cu ft cylinder may absorb between 120 and 180 SCF. We
priced the cylinder on the individual number of SCF. Just tying two
cylinders together to fill one from the other won't work well
because the matt isn't agitated. When I first started out, the matt
was asbestos and worked well. Because of the asbestos hysteria,
they converted to rock wool which worked very poorly. The wool
broke down and settled and would lose acetylene capacity after just
a few fills.
Acetylene can be handled at >15 psi, as is apparent from the above
filling procedure, if it is saturated with acetone vapor. I have
never been able to find out how the acetone stabilizes the acetylene
- even the chemist at the fill station didn't know - but it does.
BTW, have you ever seen an acetylene generator? I inherited one
when I bought the business. Came from a local foundry. They
generated their own acetylene and piped it around the plant. This
thing was really cool. The main component was a large riveted steel
pressure vessel with an inward opening hatch. It had a water tank
above with a water valve that was controlled by the pressure in the
vessel. A 50 lb can of carbide was dumped in the vessel and the
door dogged down. The water was then activated. It reacted with
the carbide to produce acetylene. When the pressure in the vessel
reached the setpoint, 15 psi, the water valve shut off. As
acetylene was used, additional water was bled in to maintain
pressure. There are usually two units so one can operate while the
other one is cleaned of the lime that's left after the reaction.
These things WOULD suffer acetylene explosions. I was told that we
inherited this unit after its sister unit exploded and the plant
decided to just buy lots of cylinders :-) Perhaps if they'd had a
way to introduce acetone, the process would be a bit safer.
BTW-2, one of the loudest explosions I've ever initiated was
compliments of acetylene. We sold weather balloons and helium in
the store. Used to tow those banner strings up in the air at the
car lots and such. One day I got the wild idea to fill one of those
with acetylene and oxygen and set it off. I built a little stand
with a steel base, a vertical tube to receive the balloon neck, a
spark plug and two gas lines. I sat the rig out behind the shop in
a field and ran gas lines out to the stand. I hooked a neon sign
transformer to the spark plug. This let me fill the balloon from a
safe distance. I bubbled both gases through medical humidifiers to
reduce the chance of static initiated detonation.
It took quite awhile and several tanks of gas to fill the thing. I
stepped back inside the store to plug in the extension cord to the
neon transformer. I thought the world had come to an end! The
explosion stripped the ground for a good 10 yard radius of grass and
dirt and gravel. It defoliated a nearby oak tree. Broke all the
windows in the store and cracked the concrete block wall facing the
blast. The gas lines were burned back a good 10 or 15 feet. Never
did find the stand.
I've set off bigger explosions but never one any louder.
From: John De Armond
Subject: Re: Neon John's Excellent "Monkey Warfare Experiment"
Date: Tue, 12 Dec 2000 04:34:40 -0500
Guess Who? wrote:
> After reading John's Big Boom Adventure, I fully understand his
> resentment toward stupid laws (and those who inforce those stupid laws)
> that stifle his creativity so.....
Only indirectly. Back then, as long as I didn't break out too many
windows or hurt anyone, the cops only came around to see what new I
had up my sleeves. It was only after government power began to
spiral out of control that my refined political beliefs began to
jell. A critical component to that gelling was the government's
lying about matters explosive, matters that I had first-hand
experience with. It dawned on me that maybe they'd lie about other
> I'll bet John is one of the few people who could actually build his
> own Rocketship, and I'd pay $100 to watch the launch! (From a safe
> distance of course)
Well, you're a few decades late but if you weren't, it would have
been free. If you have time, pick up the book "Rocket Boys" by Hank
Hickam or the movie made from it, October Sky. I don't watch much
in the way of TV or movies but the wife does. She brought the movie
home recently. She came into my shop and dragged me out to see
thing. I started watching this movie and a half hour in my jaw was
on my chest. It was practically a biography of my youth. Different
part of the country, more affluent parents and I ultimately ended up
a nuke instead of with NASA but the same story, including almost
blowing my mom up with an experimental rocket. The book is even
We lived in a house next to a vacant lot about a half mile from
downtown Cleveland. When I was about 10 years old, my uncle who
owned a huge medical and chemical supply company, decided to get out
of the chemical business and donated his whole inventory of
chemicals and labware to me, including all the old stuff that never
sold, stuff like metallic potassium and white phosphorus. By 14 I
and my hardy helpers had dug an underground bunker in the vacant
lot, poured a concrete launch pad and were building and launching
some VERY interesting rockets. One of my neighbors worked at the
Volunteer Army Ammunition Plant (TNT factory), AKA "da dynamite
plant". His contribution to the effort was smuggling TNT flake out
of the plant and donating to our warhead effort. Blew some mighty
big holes in the side of a distant hillside and in one instance of a
malfunction, in the lawn of the court house. (hehehe!)
> I think Neon John ought to look into getting himself a TV Show. (
> Does anyone besides me remember "Mr Wizard" from 40 years back? )
> John could win fame & fortune - while not having to worry about
> someone calling the law on him.
Gawd, I loved that show! It'd never fly today. The safety nazis
would be apoplectic at anything I'd do. I taught more chemistry and
physics in my back yard than the high school ever thought about and
I did it with lots of flash and booms. That's the way to keep a
non-nerd's attention for more than 5 seconds....
> It's a shame I didn't know anyone like Neon John, back when I was 12
> years old, and got that $35 Chemistry Set for Christmas.
> Who knows? I might have invented some new kind of machine that cold
> make salad mix out of old newspapers!
> Keep the stories coming. There are some of us out here who really
> know how to appreciate those kind of experiments..........
Funny you'd mention that. One of the early rough spots in my
marriage was when my wife would accuse me of lying when I'd tell her
about some of the stuff we did as kids. Then she'd meet old friends
and THEY'd tell her the same stories. One of the very few outright
apologies I've ever gotten from her followed after she heard enough
On a serious note, it's a grievous and tragic shame that the
government has made it almost impossible for kids today to gain the
same sort of hands-on experience that I got.