How to open a propane tank?

The last time I took the valve off a propane tank, it was still pressurized even after I opened the valve and it stopped releasing gas. When the valve unscrewed the tank shot about 20 ft and then spun around 3 or 4 times till the rest of the gas came out. So be careful.
 
I've used a few over the years for various projects. I always connected them to a BBQ grille to use up the last of the gas, then simply removed the valve. After that, filled it with soapy water, then drained it and cut away.

Rinsing with plain water will still leave some of the oily Mercaptan residue behind (the odor agent in LPG) making you think that there may still be gas in the tank, but filling completely with soapy water and then draining it will get rid of all of the actual propane gas and will fill it with plain old air that still smells like Mercaptan. The soapy water should get rid of most of the oily substance left behind. Cut away after that.
 
Billh50 said:
The last time I took the valve off a propane tank, it was still pressurized even after I opened the valve and it stopped releasing gas. When the valve unscrewed the tank shot about 20 ft and then spun around 3 or 4 times till the rest of the gas came out. So be careful.
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thanks; that was what I feared
 
If an LP tank has been used for a while, the some of the smelly oil will separate out. Propane will be dissolved in the oil and outgas slowly. After bleeding any residual LP by opening the valve, Unscrew the valve slightly. This will break any seal and allow any residue LP to bleed off. When it is bled, (soapy water test for leaking gas) it will be safe to completely unscrew the valve. Once the valve is removed fill with water. Drain and cut away.
 
just as a point of information...and i don't recommend anyone else trying it-

small camp stove propane cylinders did not explode when shot with a .357 mag or .22 caliber. both having lead bullets and low fuel levels in the cylinders- they sure do spin around like a top on steroids though
MYTH BUSTED
 
Ulma Doctor said:
just as a point of information...and i don't recommend anyone else trying it-

small camp stove propane cylinders did not explode when shot with a .357 mag or .22 caliber. both having lead bullets and low fuel levels in the cylinders- they sure do spin around like a top on steroids though
MYTH BUSTED
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Yup - both lead and copper are non-sparking materials. Not enough heat created as the bullet punctures and deforms the steel container to cause ignition of the gas, and definitely no spark. Result: WASTED AMMUNITION! :bang head:
 
I'm told .22 hollowpoints with a cigarette lighter flint stuck in the hollow point will produce sufficient sparks...

When you flush a tank with water, consider that wherever you dump the water will smell like gas (or rather, mercaptan) for some time. When I flushed a 120# tank and drained it in my yard, people were reporting a gas leak for several days afterwards...:eek 2:
 
propane tanks do not explode all the time like on the movies.. i forget the ratio exactly but it is like 2.? to 9.? parts per million to ignite. i routinely service lp tanks and on asme tanks when i have to replace a part, and the tank is mostly full, i open the valve (in a ventilated area) wide open until the lp freezes. then i do what i need to.
dot tanks i would connect a hose and burn off or expel the gas, remove the valve and follow some of the suggestions above.

years back i have welded on partially full gas tanks, with a torch, after inducing halon. however our govt says halon is bad. like coffee or beer
 
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