houdel
New member
And tell her she can wait until after your funeral to post the video, LOL!Please have your wife video this. Put her at a safe distance. Tell her how to post the video here.
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Process to cutting an old propane tank
- Thread starter A-one
- Start date
Excellent point regarding residual oil vapor, it will explode. I have cut several large butane/propane tanks without incident, but only after careful preparation. There are many ways to safely do it and my method might be a little over cautious but I am still here at 75 years old. I mark the cut lines on the tank. Fill it with water, (do this outside, it gets messy) then with a cut-off wheel square cut a 6"x6" square out of an upper corner of what will become a door, (save it for re-welding later) Add water to float out the residual oil on the water. There is now a large opening to prevent pressure build up if it flashes off. Torch or plasma cut the hole for the smokestacks next. It is now safe to lower the water level as the cuts progress down to the lower edge of the door. The residual oil stinks and will last forever, so after I get the tank opened up, I fill it with scrap lumber and burn it out, it's the only way to eliminate the odor.I have read the problems are not from a common BBQ or RV style propane tank, but with the large stationary tanks.
The smaller tanks have a short life and do not get re-filled very often compared to a stationary tank.
On the other hand, a stationary tank might have a service life of 30 years and be re-filled a couple times every year or more. What can happen is the rotten egg smell may condense back into a thin oil on the walls of the tank. This will seep into pores in the metal, corrosion, etc. That make it more difficult to wash out.
The tank gets retired, someone wants to cut it up into a big BBQ, they wash it out with soap and water, etc. and that will get rid of the LPG for sure. But then they start cutting it with a torch...
What happens?
The thin oil heats up, becomes vaporized, and is now in a flammable mixture within the tank! Most likely there is NOT enough energy for an explosion of significant proportions. But at the very least when it sets off you're gonna need to take a short day to go change your shorts. On the upper end of possibilities, if the tank is mostly cut through when the oil vapor lights off then there could be enough energy to toss heavy metal around and hurt someone, or worse!
I have a 1,000 gallon LPG tank I purchased from a LPG service. They sold it to me 'certified' as 'clean of LPG' by soap/chemical bath rinse. But I was warned it could 'flare up' if cut with a torch and to just take precautions for such a situation. Every hot day for three years I could smell the rotten eggs in that 'clean' tank!
Ultimately, the message I think needs to be emphasized is this: If you are not absolutely certain of what you are about to try, if you are not absolutely confident in the technique or process you are about to try, if you have any doubt about the outcome, THEN DON'T TRY IT!
This is just an opinion - I am NOT giving advice.
My opinion only, not advice or instruction.
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Craig makes an excellent point regarding residual oil vapor, it will explode. I have cut several large butane/propane tanks without incident, but only after careful preparation. There are many ways to safely do it and my method might be a little over cautious but I am still here at 75 years old. I mark the cut lines on the tank. Fill it with water, (do this outside, it gets messy) then with a cut-off wheel square cut a 6"x6" square out of an upper corner of what will become a door, (save it for re-welding later) Add water to float out the residual oil on the water. There is now a large opening to prevent pressure build up if it flashes off. Torch or plasma cut the hole for the smokestacks next. It is now safe to lower the water level as the cuts progress down to the lower edge of the door. The residual oil stinks and will last forever, so after I get the tank opened up, I fill it with scrap lumber and burn it out, it's the only way to eliminate the odor. Be careful! Never cut into ANY closed container without thinking through every safety procedure.
My opinion only, not advice or instruction.
My opinion only, not advice or instruction.
Last edited:
metalmagpie
New member
Propane is "odorized" with methyl mercaptan, a very perceptible (odor threshold is in the range 0.1 to 1.0 parts per billion) "skunk-like" odor. Some say it strongly smells of garlic. The chemical makeup of ethyl mercaptan is CH3-SH. This can be quickly and easily transformed to CH3-SO3 by rinsing in a 5% sodium hypochlorite solution (common household bleach) after which it can be rinsed away with hot water.
I have done this with 20lb propane tanks (BBQ size) by just sloshing around bleach followed by a hot water rinse. The water came out orange but no more stink.
Of course, building a big hot fire inside after cutting will de-stink a tank too.
I have done this with 20lb propane tanks (BBQ size) by just sloshing around bleach followed by a hot water rinse. The water came out orange but no more stink.
Of course, building a big hot fire inside after cutting will de-stink a tank too.