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When safe to cut a gas tank?

Discussion in 'The Hokey Ass Message Board' started by olskool34, Oct 30, 2012.

  1. olskool34
    Joined: Jun 28, 2006
    Posts: 2,597

    olskool34
    Member

    I am planning a AV8 build and the car was a running/driving car two weeks ago. I want to loose the cowl mounted tank and drained the gas. I have the cap off and after two weeks, it still reeks. Is there something I can wash it out with or something? I do not want to start cutting the tank out until the fumes are gone and I want no chances of blowing up the car or me. What do you guys use or do you let it just vaporize out after time?
     
  2. Fill it full of water and cut away
     
  3. wreckfixer
    Joined: Jun 15, 2009
    Posts: 320

    wreckfixer
    Member

    I would at least take a soapy power washer to it.
     
  4. yea, fill it full of water to chase the fumes out.
     

  5. customrod48
    Joined: Oct 10, 2010
    Posts: 201

    customrod48
    Member

    ditto on the water...............
     
  6. 91whitestang
    Joined: Oct 6, 2009
    Posts: 232

    91whitestang
    Member
    from Wisconsin

    My buddy and I rinsed soapy water through my tank like 4 times and let water run out of it for about 5 mins and took it outside and put a light to the filler on the top of the tank and it still shot out a flame about 12 feet in the air, but after that it was good to cut and weld on. Best of luck and be safe!
     
  7. The car is a 28/29 Why not remove the tank and vat it before you start
    cutting then you won't have to worry about varnish buildup catching fire. HRP
     
  8. 296 V8
    Joined: Sep 17, 2003
    Posts: 4,666

    296 V8
    BANNED
    from Nor~Cal

    Inert it with non flammable gas - argon - co2 or simply run a hose from the exhaust of a running motor.

    And before all you safety nazis chime in with your BS … Iv welded and cut on dozens of fuel tanks this way for years w no issues what so ever
    .
    The one time (many years ago) that I did try the fill it w water idea on a 55 gal drum … I almost got killed and couldn’t hear a thing for hours.
     
  9. EdselRich
    Joined: Oct 12, 2007
    Posts: 287

    EdselRich
    Member

    Just leave the tank the way it is. Or will there be clearance issues?
     
  10. F&J
    Joined: Apr 5, 2007
    Posts: 13,222

    F&J
    Member

    car exhaust with a hose.
     
  11. olskool34
    Joined: Jun 28, 2006
    Posts: 2,597

    olskool34
    Member

    Actually the car is a 30-31, no way would I ever cut up my car (avatar pic). I will let it gas out for a couple more days and pull it. Someone told me that vinegar does a great job. Ever heard of this?
     
  12. olskool34
    Joined: Jun 28, 2006
    Posts: 2,597

    olskool34
    Member


    We want to run a 35-6 dash.
     
  13. 64ONEOFF
    Joined: Nov 30, 2011
    Posts: 378

    64ONEOFF
    Member
    from Md.

    I have did it plenty of times, I have purged it with nitrogen while I'm cutting. It disapates oxegen... A friend of mine had one sitting around and cut on it without doing any prep....He almost lost his hand when it went off... Not a good thing. Good Luck and be safe
     
  14. mashed
    Joined: Oct 15, 2011
    Posts: 1,473

    mashed
    Member
    from 4077th

    Spark away. There will be a small pop, if any, from what little residual there is. Keep your face away from the open filler.

    I've watched ether used to set a tire bead. Now THAT'S scary.
     
  15. olskool34
    Joined: Jun 28, 2006
    Posts: 2,597

    olskool34
    Member


    I really like this idea.
     
  16. An old timer showed me the exhaust trick 50 years ago. Works just fine and costs nothing. I welded the tank on my bike a few months ago and it had gas in it an hour prior to welding. I'm still here and have my eyebrows and my hearing
     
  17. take a hose from the exhaust of a running engine and run it into the cap hole. let it run for 5 mins then start cutting. the exhaust displaces the oxygen and no oxygen then no fire or explosion is possible.

    leave it run while you make a rough cut to remove the tank, then you can make worry fume free final cuts.

    think about trading your good one to somebody who has a leaker to cut up

    Edit : these guys type faster
     
  18. ibuild
    Joined: Nov 30, 2010
    Posts: 83

    ibuild
    Member

    it would make be a good thing to sell the one you have and buy a old one or a cover just thinking someone could use a good one, good luck
     
  19. Candy-Man
    Joined: Mar 21, 2006
    Posts: 1,715

    Candy-Man
    Member

    Used exhaust fumes a few times.. Couldn't agree more with 296 V8....
     
  20. olskool34
    Joined: Jun 28, 2006
    Posts: 2,597

    olskool34
    Member

    Good idea on the trading it off for an old one. I will ask around and see. Fordbarn would be best I guess as not many people here would be interested in it.
     
  21. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida

    The problem isn't so much gasoline, it is the gasoline fumes. They are highly flammable and explosive. I had a guy braze up a hole in my gas tank years ago on a daily driver. He told me to fill the tank to the brim before bringing it to him so there would be no room for fumes. While he was welding it I waited down the street. :eek: He got it done and didn't kill himself, so I guess his theory had some merit.

    But I would scrub the tank out with lots of Dawn and hot water, and do it a few times, then fill the tank to the brim with cold water (so the hot water won't create fumes) and then do the removing.

    My Dad told me a story years ago about two guys he knew who were chiseling a model A gas tank out of their car and it blew up and knocked them half way down the alley. And in the boating business I was in we would hear quite often of someone blowing up their boat because of fumes in the bilge, especially if they did something like running a shop vac down there to clean it up.

    Don
     
  22. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    That makes good sense if it is a good tank that has been in use lately. The tank on my 31 sat out in the weather minus the cap for probably 40 or more years so I don't have any qualms about cutting it open. I want to run a 32 style dash in it though.
     
  23. 296 V8
    Joined: Sep 17, 2003
    Posts: 4,666

    296 V8
    BANNED
    from Nor~Cal

    The fill it w water thing is just stupid … especially if your cutting.
    Think about it …. As soon as you start cutting you start losing the water that’s displacing the fumes and the oxygen comes back and big fuckin boom!
     
  24. snaptwo
    Joined: Apr 25, 2011
    Posts: 696

    snaptwo
    Member

    I've used a couple Lbs. of dry ice puts out CO2 as it melts. Or straight CO2 from a mig bottle. The exhaust deal is fine as long as the donor car is in proper tune and not running "fat". S
     
  25. and how does running fat cause a problem ????????
     
  26. They're still teaching this method in high schools. At least, that's what the two shop teachers taught at both mine and my buddy's school.

    Best of luck on cutting that tank!


    Posted from the TJJ App for iPhone & iPad
     
  27. This is something we do almost on a daily basis.
    We have a race car fab shop, we fabricate and install fuel sumps on stock fuel tanks. This requires cutting and welding. Some classes dont allow fuel cells.
    We remove the tank from the car, drain the fuel, rinse it really good with water to get rid of any left over fuel. Then we put a gallon of laundry bleach on the tank and slosh it around really good, then put a water hose in the tank fill it with water, let run for a couple of minutes drain the tank, you should only smell bleach, not gas. As Don said its the fumes, not the gas that is the problem.
    then cut and weld away.
    We have used this method for years, never a problem.
    If fact they built three tanks today. Speedy
     
  28. 31Apickup
    Joined: Nov 8, 2005
    Posts: 3,367

    31Apickup
    Member

    Here's a picture of the inner baffels . I knew this tank hadn't had gas in it in over 35 years before I cut it. I still flushed it out with water. I started the cut with a cut off wheel and finished it using a recipricating saw.
     

    Attached Files:

  29. 270dodge
    Joined: Feb 11, 2012
    Posts: 742

    270dodge
    Member
    from Ohio

    For many years I've used a shop vac, used as a blower, to exaust the gas fumes. You might have to reduce the hose size (duct tape). Let it run while you cut or solder. I had an old pickup with pinholes in the tank and invested 7 cents in the patches. Pennys are the cheapest patches that you can buy. Way cheaper than filling with argon or such and way less mess than water.
     
  30. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida

    Uh, shop vacs are not ignition protected, the motors make sparks. Two guys were killed at a marina I worked at because they were using a shop vac down in the bilge to clean up debris and water. It literally blew them out of the boat and the boat burned to the waterline. Any electrical product like a bilge blower or bilge pump has a sealed, ignition protected motor to be safe.

    Just don't want you to get yourself killed.

    Don
     

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