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  1. #11
    Join Date
    Dec 2004


    I pulled this off the internet, but have never tried it. I suggest you get other opinions as to whether this is a safe method or not before you proceed.


    Warning: Propane is a highly inflammable gas. Make sure that the tank is completely purged of all propane before working on the tank. If you have any doubt about your ability to purge the tank correctly donít proceed.

    Propane is a gas that is heaver than air and settles in the bottom of a tank. Therefore, you will need to completely force all of the propane out of the tank. This can be accomplished by filled the tank either with water or compressed air. Either way you need to force the propane completely out of the tank

    One method is to make a long wand out of 1/2" copper and rigged it with a ball valve and quick disconnect. Then couple it to an air compressor hose. Stick it all the way to the bottom and open the ball valve 1/2 to 3/4 open and let it blow from the bottom out the top. You can start cutting immediately; just keep air blowing until you are done cutting or welding. Gas tanks can be repaired using this method also.

  2. #12
    Join Date
    Aug 2004
    Milan Michigan


    To walker, mixing air into the propane tank gives you 2 of the components needed in the triangle needed for an explosion the other componant is the torch used to cut the tank open, You may have used this method in the past and got lucky enouph to remove enouph of the propane, However this is not a safe way by any standards.
    And to Tig man, if you fill the propane tank up to the very top and leave the water in it while you are cutting there is zero chance of an explosion, so there are safe ways of doing this.
    Every tank I weld on or cut apart is done this way, I do not do this type of work without being 100% shure that there is no chance of an explosion.

    I dont mean to be rude to Walker, However the wrong methods of doing something like this can kill some one in a hurry.

    With me being a portable and shop welder I often come across dangerouse situations. Trailer hitches, steering gear boxes and steering componants are some top safety issues I come across, I just had a guy wanting me to weld mild steel to a cast steel portion of his steering shaft at the rag joint.
    He acted like I was a jerk for not wanting to weld on this, I told him dont let any one weld on it. I told him that summit would have the proper steering knuckle for his modification, I ran into him a week later and he said ( You were right) and then thanked me for the good advise.

  3. #13
    Join Date
    Sep 2007


    Quote Originally Posted by Portable Welder
    And to Tig man, if you fill the propane tank up to the very top and leave the water in it while you are cutting .
    Do you cut with a grinder, saw or torch? Do you have any problem with water coming out and getting on your equipment? I have never tried it, just seems that it would be difficult cutting a hole in something that is full of water.

  4. #14
    Join Date
    Sep 2005


    I would think if the tank was filled w/water and set for a while, drain the water off, that the propane/butane residue would be removed. Any thoughts?
    Also seems like on one of these weld forums someone spoke of purge w/carbon monoxide, but my memory isn't what it use to be either.
    Good luck

  5. #15
    Join Date
    Sep 2007



    still hoping to get a reply from Portabe Welder on this

  6. #16
    Join Date
    Nov 2005

    Default Written Procedure

    I finally found a written procedure for this (I knew I had seen it before, just couldn't remember where). This comes from the National Propane Gas Association bulletin #132-91, Recommendations for the disposition of unservicable LP-gas cylinders. "Thoroughly purge the cylinder before making any attempt to destroy it with a cutting torch or other device. Purging can be accomplished with the use of inert gases, steam, or by completely filling the cylinder with water." "Once the cylinder pressure has been reduced to the atmosphere and the cylinder has been purged, a test should be performed to verify that it is free of a combustible gas mixture before disposal. A combustible gas detector may be used for this purpose". That is the most relevant part of the bulletin-I would post the whole thing, but my scanner died. If you would like a copy, Pm me with a fax # and I'll send it to you. This is the only written procedure for disposing/cutting a propane tank that i have ever seen.

  7. #17
    Join Date
    Apr 2007



    That's exactly what I'm looking for. I went to the NPGA web site but couldn't find that publication - I think you have to be a member to download it.

    I also found references to this publication:
    Item: 000130
    Title: Purging LP-Gas Containers

    I'm going to give them a call tomorrow and see if I can order them. If not, Iíll take you up on your offer to fax it.

  8. #18
    Join Date
    Dec 2005

    Default added link to welding manual

    Gary, I have a Military CD (Welding,Stick,Mig &Tig)that explains how to do it and it also has a bunch of other things about welding that I'd be glad to email you or anyone else wanting it..I bought it but it says it can be distributed freely because it's public information. The method they say use is the same as my cousin used for many years at a large welding-fab shop and he never had any problems with this method. Basically you drain the tank and flush with plenty of water and then hook a car exhaust to a steel flexible pipe and run exhaust into the tank for several minutes to purge the tank then start cutting after checking with gas detector...My cousin kept the exhaust running into the tank while he cut or welded because he said the exhaust had carbon monoxide in it and wouldn't let anything burn because it took all the oxygen out of the tank and you got to have oxygen to burn or explode. I myself have welded and cut on a few tanks doing this but was always nervous while doing it. As the old saying goes please donít try this at home! Anyway it says you can also use steam, Iíve never tried that but the car exhaust thing always made me feel a little bit better thinking it was taking the oxygen out of the air too. I donít think there is a 100% safe way to do it. I got a friend here locally that has been welding since he was a kid and has a large welding-fabrication shop and a few years ago he burnt about half of his shop up cutting open a propane tank and he had cut hundreds telling how many small ones he cut open to make feed troughs out of. Like I said Iíve did it before and Iíve got a 540 gallon propane tank right now that needs the ends cut out but Iíve decided Iíll rinse and purge with exhaust and leave the exhaust running and cut the first end out with a sawÖI want to live to see the grandkids grow up and marry *LOL*
    I also have a friend that had did this hundreds of times and he uses a lawn mower exhaust on the smaller tanks.
    Guys here's link to a welding Cd with info on this and a bunch of other things..I'll leave it up for a few days so feel free to download it. Hope this helps, Farris

    here's the link

    username : welding
    password : arkansas
    Play Safe / Be Safe!
    A Friend, Farris

    Play Safe-Be Safe!

  9. #19
    Join Date
    Dec 2005

    Default Illegal

    Quote Originally Posted by jolane
    Can I add to the question? How would you safely cut open a refrigerant container. I have some (look like 20lb propane tanks, but green) that I would like to cut and use. I think they are from R12, and are empty.

    Be careful cutting refrigerant tanks open because it's against the law (EPA)
    They put a local man out of business for doing that..they fined the heck out of him and he fought it and spent a bunch of money and still lost. They said some of the tanks still had some in them and he was releasing it out into the air.
    Hope this helps, Farris

  10. #20
    Join Date
    Dec 2005


    You need three items to have an explosion with a carbon base fuel

    Oxygen, Carbon, Ignition

    O/A= Oxygen Acetylene

    Think about the above for just one minute and see if it doesn't dawn on you what your fixing to do!

    Well I'm removing the Oxygen! yep you sure are and as soon as your torch pops out during the cut, it'll filler right back up with?..... with?...
    Oxygen and Carbon

    There's been more than one person from heaven that stated:

    Gee's I wish I wouldn't had done that

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