Cutting fuel tank

  1. hal 1 Member

    Messages:
    63
    lancs england
    Help needed, Last time I took something to be sandblasted someone else had left a fuel tank to be blasted, they'd cut an opening in the top so the inside could be done.
    I'm now thinking along the same lines, when I got my tank there was a small amount of old petrol in there, I emptied it and left it in one corner of the garage, that was about 6 months ago.
    Now, my question is how can I cut a hole without the risk of blowing myself up ?


    FYI the tank is from a Marcos, It's mild steel, I can get an aluminium one for about £400 but looking for cheaper alternative
     
  2. Wildefalcon Member

    Messages:
    179
    Location:
    Gloucestershire, England
    I wouldn't. The petrol soaks into the steel.
    The recommendation is to stream clean and then fill the tank with co2 before introducing anything sparky.

    Google fuel air bomb.

    Look into the frost restoration tank in a tank treatment for the inside, and a zinc based paint, epoxy stuff for the outside.

    W.
     
  3. Pete.

    Pete. Member

    Messages:
    8,271
    Location:
    Kent, UK
    Course it doesn't. It might get into seams and it might put a gummy varnish on the surface that might produce a volatile vapour when heated but one thing it certainly does not do is soak into steel.
     
  4. brightspark

    brightspark Member

    Messages:
    26,846
    Location:
    yarm
    fill it with water and get cutting . job done :laughing:don't over think it
     
  5. pedrobedro

    pedrobedro Man at Matalan

    Messages:
    9,805
    Location:
    CX Derbyshire
    Steel is not porous, how does this work ? There will be vapour and the tank needs purging before you do anything to it but blasting inside a tank is not going to be much good unless you cut it in two halves so you can see the results. If I was going to cut it I'd drill a hole then use a nibbler or snips.
     
  6. brightspark

    brightspark Member

    Messages:
    26,846
    Location:
    yarm
    as above no use sandblasting better off using chemical rust removal if u must
     
  7. rtbcomp

    rtbcomp Moderator Staff Member

    Messages:
    18,615
    Location:
    Sheffield UK
    Even if you do sandblast through an existing hole you still need to purge as blasting produces sparks.
     
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  8. hal 1 Member

    Messages:
    63
    lancs england
    The tank is about 30" X 20" and I would cut a hole about 20" X 10" in it, hopefully this allow room for the blast gun and to see the result.
    The steel is quite thick so I think I'd struggle with snips
    What about power washing inside before I start ?
    Or maybe I'll try filling with water, that might be the best thing.
     
  9. slim_boy_fat

    slim_boy_fat Forum Supporter

    Yep, just be careful if you decide to use an angle grinder - not for explosion risk but getting the electrics wet, elektrickery can kill......;)
     
  10. hal 1 Member

    Messages:
    63
    lancs england
    Yep, just be careful if you decide to use an angle grinder - not for explosion risk but getting the electrics wet, elektrickery can kill......;)


    Yes, did wonder about that, just realized I have an air powered saw and angle grinder, dead cheap jobs from Aldi, not used before, have to find them now, buried in the depths of all the other s**t that ' will come in handy one day '

    Thanks
     
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  11. ranchero Member

    Messages:
    79
    Location:
    southampton
    I take out the petrol gauge sender unit. then purge with air, then with the air still flowing cut it open with a plasma
     
  12. addjunkie

    addjunkie Member

    Messages:
    5,174
    Location:
    Northumberland. Reet oot in the sticks
    Fill it to the brim with hot soapy water, give it a good slosh about, the heat liberates the hydrocarbon vapours. Drain it. Then fill with either exhausts gas from your car, or mig gas, to eliminate the oxygen, give it a good purge, better still leave a trickle in there while you cut.

    Or is use option b...in the garden arms length, head low, put a match to the hole and hope for the best.

    Purgeing with air will help remove vapiurs but air contains oxygen and is also part of the fire triangle.

    If you have the stoicheometric ratio between the fuel and air correct it will ignite very easily. May as well just use option b.
     
  13. Robbie260 Member

    Messages:
    520
    Location:
    Scotland highland
    We had to weld an oil tank on the ship ounce we dropped a whole load of dry ice into, that was the atmosphere purged.
     
    Pete. likes this.
  14. Pete.

    Pete. Member

    Messages:
    8,271
    Location:
    Kent, UK
    Purging with car exhaust can be no less of a hazard. Carbon monoxide and hydrocarbons are both flammable - and also part of the fire triangle.
     
  15. puddles2 New Member

    Messages:
    13
    Location:
    usa
    here in the states we flush with hot soapy water , then use small amount of nitrogen or argon flowing in 1 end of tank and out the other while welding, carbon dioxide also works well and can be obtained where fire extinguishers are refilled fairly cheaply and used in an old disposable mig gas cylinder hope this helps be safe
     
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  16. Pete.

    Pete. Member

    Messages:
    8,271
    Location:
    Kent, UK
    The few ally ones I've done I just emptied and left in the sun for a couple of hours.
     
    brightspark likes this.
  17. addjunkie

    addjunkie Member

    Messages:
    5,174
    Location:
    Northumberland. Reet oot in the sticks
    Yes but 100% co will not burn. As you are above the upper explosive limit. Hence why the world over oil tankers tanks are blanketed with it.
     
  18. magicgrotto Member

    Messages:
    79
    Location:
    doncaster
    :scared:Buy a petrol tank sealer kit ! Then you wont have to bother cutting it up! Be it I was a good SHOT with a match in my YOUNGER Days ! LOL
     
  19. hal 1 Member

    Messages:
    63
    lancs england
    I did think about that once but the tank still needs some welding doing, the tubular filling pipe has rusted and needs replacing.
    I got the price wrong for a new tank they're actually £525 !
    Apparently the reason why they rust is because lead free fuel doesn't ' coat ' the inside of the tank which allows rust to form, this is because the cars aren't used enough and are sometimes laid up over winter, or so I hear.
    I think I'll go the way of washing it out, good rinsing, fill with water and then cut with air powered tools.
    If I hold the tool at arm's length and squint my eyes I should be OK:thumbup:
     
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