Varnish in Gas Tank

Discussion in 'Gas Engines' started by jakestevens7, Apr 19, 2011.

  1. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    You need oxygen at a fairly narrow percentage (I'll guess around 6% to 10%) range to cause issues and most of the time, with diesel there isn't enough to promote combustion. I've welded on diesel tanks countless times and the easiest way to avoid trouble, is to start up a diesel and put a hose on it's exhaust pipe, then bring this to the filler neck of the diesel tank. This floods the tank with diesel exhaust and not enough oxygen is present to start anything. I've won countless 20 dollar bills from folks swearing, the cigarette hanging from my lips was going to blow up the fuel I was dispensing or tank I was welding, but all I've ever gotten is other people's money and a fixed dozens of tanks.

    Personally, if it was me, I'd consider just using a standard tank cleaner, drop some pee gravel in the tank, shake the crap out of it, then fill it and run it with the knowledge you'll be changing multiple fillers for the first several hours of operation. I've seen some really bad tanks just burn off the varnish with a few hundred gallons of fuel and fuel cleaners and stabilizers. Yep, it'll run like crap for a bit, but it all burns (mostly).
  2. Frosty

    Frosty Previous Member

    Psssst,--its a 130 gallon tank.:rolleyes:
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    So. This just makes it more entertaining, but the idea still works and it's fairly easy. Yep, everything needs to be a lot bigger to handle the tank, but nothing a 1 HP electric motor and a counter weight wouldn't solve . . .
  4. cor
    Joined: May 2008
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    cor Senior Member

    I was at an automotive junk yard a few years back when I saw an employee working on a huge pile of gas tanks from cars. They have to remove all the tanks from the cars and get rid of the fuel from them before they crush them and send them to the scrap metal company. There must have been several hundred tanks in the pile.

    If you have ever tried pour the gas out of an old tank you know that it is just about impossible to get it all to run out of the filler neck no matter which way you turn it. His solution was to use an ax to chop a hole in the tank so that he could pour the gas out easier.

    I commented to him that it looked like a scary job. He replied that he "sees an occassional spark when chopping, but hasn't blown up yet"!

  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Combustion is a fairly difficult thing to get right, unless you not planning for it (at least it seems). The occasional spark from an ax blow probably will not do anything exciting. A pressure wave from the blow, will probably insure the spark sees no gas fumes before it self extinguishes.
  6. Frosty

    Frosty Previous Member

    Mythbusters last night shot high speed bullets straight through a fuel tank.It was suppose to blow up like what it should when Bruce Willis is around, it of course did not.

    They also put bleach in the gas stank , moth balls , a penny down the carb and the final was bleach in the oil to which it seized,--- now there was a surprise.
  7. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    alcohol solves varnish very well.
  8. MengWalton
    Joined: Jul 2011
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    MengWalton Junior Member

    Made me laugh, no seriously you should be ok with diesel fumes, its unbeliveably hard to get the correct fuel to air ratio inside a tank with diesel, I used to drop a cigarette into a fuel tank that a cadet was just about to clean, never seen someone run so fast, obviously it just went out, or sometimes it used to get a small 'Whoosh' and a bit of flames, harmless, remember just be safe, just because it doesnt happen most of the time doesnt mean it can't, dont do anything your not confident in doing, thats when mistakes are made and people hurt.
  9. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Meng, I've won more 20 dollar bills doing just that, then you can imagine.
  10. thudpucker
    Joined: Jul 2007
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    thudpucker Senior Member

    Just a thought. Whenever I had to do some Welding etc on a fuel tank, I always put some diesel or Kerosine in the tank for awhile to soak the Shellac out of the Crooks, Crevices and Crannies, before I put the heat to it. That includes drilling, Riveting etc.

    You dont get those nasty "WHUUFFFS" as some Gasoline Residue burnes.

    Then maybe you can put some kind of a spray pressure washer down in that tank to wash the Diesel down, and THEN the Shop Vac will work just fine.

    But I have to say this about that. In all the old boats, old tanks, etc that I've come across, the new Fresh Gas just dissapated the Shellac to the point the Fuel filter caught it. I wonder if your chasing a problem that lives in some other part of the fuel system?

    I once started a 32 Plymouth that had been in a Garage for 15 years. That old Gas never botherd it a bit.

  11. Carteret
    Joined: Jan 2004
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    Carteret Senior Member

    A pump with a Nitrile impellor will do the trick.
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