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Building an aluminum gas tank

Discussion in 'The Hokey Ass Message Board' started by grovedawg, Jan 10, 2012.

  1. grovedawg
    Joined: Oct 20, 2009
    Posts: 451

    grovedawg
    Member
    from Heber, UT

    I'm starting to build two aluminum gas tanks and wonder if there are things that I should be aware of before I install it? If I weld it thoroughly (which I will) it shouldn't leak. But should I seal it regardless? What would work as a sealer? I'm going to run baffles, and then weld the top on.

    Any HAMB'ers out there who've trodden this path that would like to pass on their wisdom? Thanks, Ryan

    PS. Here are pics of my progress so far. I've welded the sides, and the bottoms in. I've yet to weld in baffles, and cut holes for the sending unit, roll over valve, and pick up tube. I may also weld a bung at the bottom so I can drain it if I ever need to.
     

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  2. Flatheadguy
    Joined: Dec 2, 2008
    Posts: 2,037

    Flatheadguy
    Member

    I am sure that others will add to this response. Designing and fabricating fuel (and oil) tanks for various aircraft, aerobatic and classics/antiques, I do not do anything after TIG welding and leak checking. There is no sealer, that I know of, that is FAA approved for slosh-sealing, coating, the interior of aluminum tanks. The problem, potential or not, may be the various additives that are used in modern pump gas. And, just my opinion, if it isn't used in aircraft, it's not likely to be suitable for automobiles. Stand by for more information from others. Pros and cons.
     
  3. WCRiot
    Joined: Feb 20, 2009
    Posts: 193

    WCRiot
    Member

    Pressure test it for leaks and call it a day.
     
  4. RPM
    Joined: Feb 5, 2005
    Posts: 204

    RPM
    Member

    We build a lot of gas tanks and we pressure test them with air and check for leaks with soapy water.
     

  5. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    I had a 1/4" plate welded in the top [about6" sq.] in case I want to drill & tap another fixture of some sort .. think ahead..
    dave
     
  6. Methanol in todays fuel will be a problem down the road ...WHY... Methanol/alkahol is highly corrosive especialy to aluminum, most racers that use alum/tanks drain them after use. The better grade it is the better it resist corrotion 6061 t6 is best .I however would strongly recomend stainless steel for your tank for todays fuels JMHO.....
     
  7. grovedawg
    Joined: Oct 20, 2009
    Posts: 451

    grovedawg
    Member
    from Heber, UT

    How would I go about pressure testing it with a huge filler tube? I'm sorry if this is a dumb question, but I want to get it right. Thanks for your response dudes.
     
  8. Flatheadguy
    Joined: Dec 2, 2008
    Posts: 2,037

    Flatheadguy
    Member

    RPM, reply number 4 above, has it exactly right. Test with VERY LOW air pressure.
    1.5 to 2 psi. USe soapy water and a brush. Go over the welds with the mix and look for bubbling. Heavy plate on any surface is not necessary for possible future fittings. Get weld bungs...1/8....1/4.....pipe thread. Weld 'em in and screw in a plug.
     
  9. Use a piece of hose, a pipe plug, and a couple of clamps.
     
  10. grovedawg
    Joined: Oct 20, 2009
    Posts: 451

    grovedawg
    Member
    from Heber, UT

    The cost for the same quantity of stainless steel was more than double that of the aluminum... :eek:

    Is there anyway to keep the aluminum from corroding? If not I'll store that info for later and call it a loss until I have to build a new one.
     
  11. grovedawg
    Joined: Oct 20, 2009
    Posts: 451

    grovedawg
    Member
    from Heber, UT

    Cool. I've used soapy water to find leaks before.
     
  12. 48 Chubby
    Joined: Apr 29, 2008
    Posts: 1,014

    48 Chubby
    Member Emeritus

    Go to a plumbing supply house and buy an expandable rubber plug. They are available in sizes up to 10 or 12 inches and are fairly cheap. Unless you are fighting a rust issue, tank coatings often create more problems than they solve.
    In the pics that aluminum looks to be about 1/4''?:eek: Heavy duty tank!
     
  13. Bicycle inner tube and a hose clamp. Already has the schrader.Also will keep you from putting too much air pressure in there. Be careful .

    That trick works good for radiators too
     
  14. Rookie1
    Joined: Apr 5, 2009
    Posts: 63

    Rookie1
    Member

    I would look into at least applying epoxy to the welds, they may not leak air or water but they will seep. I've worked on fuel tanks (for large generators) that have had it poured in and capped then tumbled to coat the inside. Water Glass (sodium silicate)works also .
     
  15. grovedawg
    Joined: Oct 20, 2009
    Posts: 451

    grovedawg
    Member
    from Heber, UT

    A Bicycle tire is a great idea. Thanks
     
  16. grovedawg
    Joined: Oct 20, 2009
    Posts: 451

    grovedawg
    Member
    from Heber, UT

    It's .120 wall thickness. I didn't want to worry about it. EVER. :D
     
  17. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    If you wanted to install a late model in-tank pump & needed a LARGE access hole, you'd be glad you had a tappable plate... think ahead...


    dave
     
  18. #1 Make sure you run a very fine fuel filter as there will be particlates contaminating the fuel down the road. #2 you could use avation gas (no methanol) just costly also or #3 use stabil for marine aplacations and you will probably be ok.... Good Luck... Looks like a real nicely enginered tank by the way..:cool: .
     
  19. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,476

    dreracecar
    Member
    from so-cal

    O'Boy here we go

    First thing is that the material you should use is 5052 H32 , Its a material that was designed for marine use and of all the alu. out there it is the least corrosion sensetive. Thats why they use it in boats.
    Second is that one should never build a tank that large from pieces,You should bend the shape as much as you can and then overlap the final seam so that the load is not directly on the weld. By welding mutiple pieces you can develop fractures along the welds. The only way to prevent that from happening is to edge the pieces first either with a radious or a bend and butt weld the two together and you will notice that when the part is welded properly that the drop-thru shows as a back weld bead but the stress will be on the whole radious.
     
  20. 19Fordy
    Joined: May 17, 2003
    Posts: 8,027

    19Fordy
    Member

    EXCELLENT SUGGESTIONS. You want to have a few welds as possible.
     
  21. I am never to old to learn something new .Thanks dreracecar...John...:cool:
     
  22. socalmerc
    Joined: Feb 24, 2008
    Posts: 475

    socalmerc
    Member
    from socal

    where did you get your gas cap filler neck?
     
    Last edited: Jan 10, 2012
  23. grovedawg
    Joined: Oct 20, 2009
    Posts: 451

    grovedawg
    Member
    from Heber, UT

    I'm glad this is up now, so that someone won't make the same mistakes. Thanks for the tips.
     
  24. grovedawg
    Joined: Oct 20, 2009
    Posts: 451

    grovedawg
    Member
    from Heber, UT

    Most likely I'm going to weld one up, and connect with a small bit of gasoline proof hose to the tank itself. Google search around and you can find some that are made to be welded in (or soldered).
     
  25. XXL__
    Joined: Dec 28, 2009
    Posts: 2,117

    XXL__
    Member

    I made an aluminum tank for my hooptey almost 10 years ago. I buy whatever crappy gas is available (most around here is 10% ethanol). I haven't experienced any visible corrosion, and both filters (front and rear) are clean. Not sure what corrosion issues others have had.

    Edit: I used 5052.
     
  26. 32 hudson
    Joined: Mar 5, 2005
    Posts: 778

    32 hudson
    Member

    I got my fuel filler neck and cap from coyotte_gear.com and they have an epay store also.
     
  27. Hi guys, I'm a newbie and came across this site on Google. I have worked on a few kit-cars and have lengthened a van and fitted a V8 Rover engine to it. I drag-race a Hayabusa drag-bike at the moment (still getting the hang of it) as I used to ride my double-engined Triumph 'Two Faced' back in the sixties here in the UK. I am 71 now and currently in remission from cancer. Over the years as a spin-off from my drag-racing and making bits for myself and others, I have learned to weld aluminium with oxy-acetylene and have made many ally tanks and fairings. I have put a video together to show how I make a motorcycle petrol tank and it is for the guys who want to have a go themselves--it's not a commercial video. I'm self-taught and an electrician by trade. I usually use 16 swg aluminium for motorcycle tanks but have used that for a 6 gallon tank for my mate's cobra replica but anything bigger and I would suggest using 14swg. If this thread is still active I could post a link to my video if anyone is interested. Cheers for now, Pete. Warrington, Cheshire, UK.
     
  28. Ted H
    Joined: Jan 7, 2003
    Posts: 312

    Ted H
    Member

    You might post a teck article and tell us how you got those magnets to stick to aluminum. LOL!
    Ted
     
  29. ANDEREGG TRIBUTE
    Joined: Jan 1, 2008
    Posts: 1,385

    ANDEREGG TRIBUTE
    Member
    from Bordertown

  30. Hi Pete - you're a brave man!! I'm 20 years younger and get windy on my moped ;-)

    If you are building ally tanks then I have some kit car owners who would be interested.

    I prefer ally to stainless - stainless has a bit of a catering industry vibe for me.

    I'm over in Chester and currently building a steel 27T Modified.
     

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