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Respect Compressed Air

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MrDan

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#1
This one happened back in the 70's, when I was a green kid out of high school. I worked in a auto body shop. We had a huge compressor with a 120 gallon receiver. It was a 2-stage compressor and so the cutoff pressure was 175 psi.

I needed another air line, and the tank had a 2" galvanized steel plug on one end. I decided to replace the plug with a bushing reducer down to 3/4" pipe and hook my new line in there.

I shut off the compressor and opened the little 1/4" drain valve on the bottom of the tank to relieve the pressure, but it was taking forever.

I loosened up the 2" plug a little, so that some air was leaking past the threads to try and hurry things up. Still slow as molasses.

Finally the pressure was down to around 25 psi. That didn't seem like much at all to me, figured I could just finish unscrewing the plug and catch it as it came off. :dejected:

Fortunately I was standing to the side, as the plug shot out of the end like a cannonball. It went right through a doorway and into the field next door. We never found it.
 

kvt

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#2
Where did the wrench you were using wind up.
 

MrDan

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#3
It put a dent in the wall...
 

Tony Wells

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#4
I did something along those lines when I was a kid, with my uncle's compressor. Wanted to put a new gage on it, and it was in that end port, bushed down to 1/4 NPT. Pressure was low, as I was thinking at the time, so I proceeded to unscrew it by hand. When it turned loose, I managed to keep hold of it, but the my hand was filled with tiny pieces of rust and debris, like it was shot with rat shot or something. I picked out all I could, and had to keep iodine on it for a few days. And I will always remember that. I was about 10 I guess, but even a few PSIG can do some damage. Yep, respect your air pressure.
 

cathead

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#5
Another dangerous thing to do can be to spin up a ball bearing with an air hose nozzle. It can be done safely with care
but don't try to see how fast it can go as it can fly apart with disastrous results.
 

kvt

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#6
I can attest to that one, just a little to much air on the bearing and all of a sudden there is an explosion of parts, and those little balls hurt, How does a ball that size go through such a small hole in the skin.
 

jim18655

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#7
I was working on a townhouse project and the plumbers air tested the water lines at about 100 psi. The apprentice went around to drain the air and remove the test caps. He got the order wrong on one or two units and just put the torch to the cap. It blew across the small kitchen and stuck in the dry wall. He was lucky the hot cap didn't hit him.
Airless sprayers can inject paint into the skin also.
 

mzayd3

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#8
Yup, learned this one the hard way!


Sent from my iPad using Tapatalk
 

FOMOGO

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#9
Yes, air can be dangerous, and compressed gas bottles, and hydraulics even more so, not to mention angry wives and girlfriends . So lets all be careful out there. Mike
 

jocat54

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#10
Oil field grease injectors will lube you right up:grin: Don't ask.
 

bcriner

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#11
I found out the hard way how dangerous airless paint sprayers can be. I shot myself in the end of my finger and filled it with an oil based paint. The surgeon split my finger open to clean out the paint, he worked on it for about 2 hours but wasn't able to get all the paint out. I spent the next 4 days in the hospital and finally after a very painful 6 weeks they finally took the finger off. It took about 3 months to finally regain full use of my hand. Guys be careful out there.
 

Kevin J

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#12
I had a 1979 Dodge pick-up and one of the front disc brakes locked up at 12,080 miles just over the 12,000 mile warranty. No help from the dealer so I decided " sure I can fix it myself". Got the caliper off and discover that the piston was a composite material. The new air compressor seemed to be the logical tool for this job. Put some air through the caliper and success, it came out, but violently. Unfortunately I was watching the progress a little too closely and it nailed me in the forehead. New metal replacement pistons were available making me think this was a common problem.

Kevin J.
 

dave2176

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#13
While working in a dealership many years ago we had a mechanic add some hydraulic oil to the in-ground automotive lift. Success! The lift didn't jump anymore the last two inches where it ran on just air when the oil was low. He decided to help the mechanic in the next bay and top off his lift as well. He stuck a 3/4" impact gun in the plug and zip out came the plug along with several gallons of oil powered by a whole bunch of air pressure. The mechanic who removed the plug landed on the other side of a nearby car with most of his teeth missing and his nose broken with oil and blood making his hair stand straight up when he looked up over the hood of the car he landed by. The mechanic who was removing a transmission under the car that just lost hydraulic/air pressure needed a change of pants when the hoist dropped several inches before catching on the safety lock.

Be careful,
Dave
 

ch2co

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#14
As a youngster, I was warned about using air hoses carelessly. "Son, never point an air hose anyway near your skin. You can shoot a blast of air right
through your skin and into an artery and bam! it will go right to your heart and kill you." I have always respected air hoses ever since, and that was MANY
years of air hose use since, and Im still here!;)
 

FanMan

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#15
Another dangerous thing to do can be to spin up a ball bearing with an air hose nozzle. It can be done safely with care
but don't try to see how fast it can go as it can fly apart with disastrous results.
Is THAT why they always say not to do it? I always assumed it was because it could damage the bearing running it dry. Well, I guess that counts as damage... :eek 2:
 

Cactus Farmer

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#16
Years ago, I was checking out a compressor/tank combo and the unloader was a type that was unfamiliar. We filled it with air several times to test and finally the owner was tired of waiting for it to drain and unscrewed the 1 1/2" plug on the end of the 80 gal. tank. It was pointed between two houses and since it was fall, a large amount of leaves were ejected out into the street. Traffic came to a screeching halt! At the time it had about 80lbs, which is 400+ gallons of air coming out of that small hole like a jet. Fred, the owner was warned before he did the deed by me and then he learned a lesson! And he never forgot it either!!!
 

graham-xrf

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#17
While working in a dealership many years ago we had a mechanic add some hydraulic oil to the in-ground automotive lift. Success! The lift didn't jump anymore the last two inches where it ran on just air when the oil was low. He decided to help the mechanic in the next bay and top off his lift as well. He stuck a 3/4" impact gun in the plug and zip out came the plug along with several gallons of oil powered by a whole bunch of air pressure.
Dave
Loosening a hydraulic connector when the system is already bled is undramatic, and pretty safe if the connection is of the type that indirectly leaks to a side hole. BUT .. if there is still air in there, it stores energy like a spring! Not quite like death by diesel injector, but it is true that a squirt of hydraulic oil into below the skin is pretty much the end of all.

My direct experience with trying to vent Argon from a HIP (Hot Isostatic Press) out into the exhaust pipe...
From cooling back from 900C to below 300C, the pressure had reduced a bit, but was still at 800Bar (11,600psi).
The vent valve opens into only 1mm hole, which then ends up in a sort of "communal" exhaust about the diameter of a spray can.
The final vent pipe was 1/2", meaning it was 3/4" OD, in stainless 316. The problem was with the "communal" part being shared by a oil filled vacuum pump.

I never would have thought that one could blow hard enough through a tiny 1mm hole to make enough pressure in a 1/2" pipe open exhaust to blow back through the gaskets of a vacuum pump, and generate an expanding mist of white oil fog - that is oil bubbles filled with Argon.

Panic! It spread through the whole lab, filling up from the floor. I reached down into the fog, and spun the needle valve shut, but by the time we had made our way out, it was waist high, and I was tripping over all sorts of machinery under it. In 30 minutes with loading bay doors wide open - it was all gone, but the fright has stayed with me! Breathing reaction is driven by CO2. A lungful of Argon will stop you breathing!

Gas under pressure is just dangerous stored potential energy. The work the compressor has to do to get it there could have driven you somewhat far down the road. High pressure gas is something that you treat with very, very special care - as if it was dynamite!
 
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woodchucker

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#18
I remember my dad was shooting a c02 pellet gun in the basement. He thought it was out of CO2 and loosened the cartridge. He said it removed a good amount of concrete from the wall when it shot out. A little co2 gun that could barely shoot through anything but targets, but that canister could take out concrete. I learned respect for pressurized vessels at that point..
 

xman_charl

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#19
working at 16 wheeler truck place, repairing flats...changing tires...
use 3/4 inch airlines
recall disconnecting quick change, blew a scab right off my arm
be careful with those quick disconnects!!

Charl
 

Hidyn

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#20
be careful with those quick disconnects!!

Charl
And always put the side of the coupler that cuts off the air, to the air supply side. I sure felt stupid popping one of those off with the coupler set up the wrong way around and I would have felt a lot worse if I had been whipped by the loose end.
 
B

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#21
Back at school we had a 220 bar hydrogen cylinder about 5 feet tall fall and neatly shear off the valve - when we could hear and think again we saw the hole through the concrete block wall, the fence, the school head's new car... it came to rest in a field after passing through a brick wall on the far side of the car park :/

I'm still scared of gas cylinders.

Dave H. (the other one)
 

extropic

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#22
On a lighter note, once upon a time, I slid the sleeve back on a quick connect coupling so the plug/hose popped out. The hose end did a backflip and smacked my girlfriend on the top of her foot.
She was not at all happy. Acted like suffering the most pain since child birth.
Subsequently, I noticed she paid a little more attention to the proximity of air fittings.
 

extropic

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#23
I was on the verge of calling BS regarding the multiple references to unscrewing the 2" plugs/fittings on an air receiver.

When I've had to remove them, there was nothing casual about it. It took a 24" pipe wrench + cheater, had to tie the receiver to the wall and apply all the grunt I could muster.
 

extropic

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#24
I just remembered that I was once responsible for a potentially life threatening laps of intelligence with compressed air.

In about '78, my employer bought a used 4' kick sheer that had been converted to pneumatic by a previous owner. When it arrived it had a 4x4 lagged under each support leg. I figured they were there for transport purposes only and removed them (the importance of this will soon be clear). The sheer was in rough shape so I took bits apart and made adjustments/repairs as I thought appropriate. After reinstalling the air cylinder and treadle, I decided to use air to retract the cylinder. I put a nipple on a hose from the cylinder and plugged it in to shop air.

!!! BAMMM !!! The cylinder EXTENDED and the treadle hit the floor causing the machine to flip onto it's back. !!! BOOM !!!

The 4x4s were needed to clear the travel of the modified treadle. And, obviously, yours truly charged the wrong hose.

People came from distant parts to see WTF? No physical injury befell any persons (thank God) or the sheer (small dent in the concrete floor).

My embarrassment hit a new record high and I suffered additional discomfort from the massive, instantaneous injection of education. That was bad, but I feel much better now.
 

Hidyn

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#25
I would have definitely removed the 4x4's as well... it's unusual to see machine modifications made of wood :/
 

Rustrp

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#26
Finally the pressure was down to around 25 psi. That didn't seem like much at all to me, figured I could just finish unscrewing the plug and catch it as it came off. :dejected:
Ahhh, youth. I have something similar. I was unscrewing the valve, it quit hissing so I though the pressure had bled off. One quick turn an BAM, 300 psi of oxygen sent the valve ricocheting off the fuselage three or four times before it stopped. No one was hurt and I never found the valve. :D
 
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#27
Back at school we had a 220 bar hydrogen cylinder about 5 feet tall fall and neatly shear off the valve - when we could hear and think again we saw the hole through the concrete block wall, the fence, the school head's new car... it came to rest in a field after passing through a brick wall on the far side of the car park :/

I'm still scared of gas cylinders.

Dave H. (the other one)
This reminds me of several stories I've heard over the years. One in particular, happen at a company over on the east side of Houston on Navigation boulevard. Anyone who deals with the oilfield may know of whom I'm talking about. The incident took place in the 1970's. They were testing a tool with nitrogen in a piece of pipe when a 3-1/2" Pipe bull plug let go at around 5,000 psi. It went thru a cinder block wall across Navigation Boulevard and who knows where it went from there. It was never found nor did it take out any cars in it's path on that busy street!
 

Superburban

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#28
Don't clean your hands with a pressure washer. :eek:
 

epanzella

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#29
I had built a wood powered boiler with a storage tank the was 5x5x5 feet. Across the centerline of the tank was a steel bar anchored on each end by a 1/2 inch grade 5 bolt to prevent bowing. I was planning on running the tank pressurized to 10 psi so I was testing it with my compressor. While slowly increasing the pressure one of the bolts sheared right off and I was only at 3 psi. Doesn't sound like much but 3 psi over a 5 x 5 ft area is over 10,000 pounds of force. I ended up venting the tank to the atmosphere.
 

benmychree

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#30
I can attest to that one, just a little to much air on the bearing and all of a sudden there is an explosion of parts, and those little balls hurt, How does a ball that size go through such a small hole in the skin.
Another thing one can do with compressed air is to take a large hex nut and spin it on a screwdriver shaft with your air nozzle to the point of it screaming and then tilt the driver downwards so the nut creeps off the end and hits the ground and goes flying like a bat out of hell ---- of course do not attempt this at home!!!! Apprentices where I worked were known to do this caper and scare the S--- out of whoever was in range; none that I aimed at were unable to get out of the way.
 
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