Problem welding air compressore tank

  1. daleyd

    daleyd Member

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    Location:
    Wrexham, North Wales
    You sure?
     
  2. Seadog

    Seadog Forum Supporter

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    6,972
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    NE London - UK
    My compressor has a test rating 50% above operating pressure.
     
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  3. zeppelin builder

    zeppelin builder Member

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    1,501
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    peoples republic of scotland
    i would get someone that can weld to do it
    6013 will be just fine , propane cyls despite there chunky appearance are only around 2mm thick , best practice is to weld a compensating plate on first "think big washer about 6mm thick prepared so that the pipe is being set into the countersunk hole ,that way you get fusion into both surfaces and can leave a bit more of a fillet weld
    safety of course should be seriousely taken
    on any used fuel vessel , should be wet steam cleaned and purged during welding

    glass fibre propane vessels are fairly common we had them run off a rig in denmark as we were using them for pre heat
    on welding ops not realy a good idea !
     
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  4. daleyd

    daleyd Member

    Messages:
    7,101
    Location:
    Wrexham, North Wales
    Same as mine - I've never heard of anything as high as 3 x pressure for testing anything, certainly pipework was always 1.5 X working pressure (Though it's been an age since I was involved in anything to do with that). I would have thought that testing stuff to 3 X would place completely unnecessary stresses on fittings, welds etc.
     
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  5. Memmeddu

    Memmeddu Member

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    TBH it's what I'll do on a project .
    I will use a CO2 bottle which is tested for 300MPa (300bar ) , I'll drill a hole and weld an ½" NPT female fitting to it .
    Then I'll test it at 30 bar but it will work at maximum 10 bar
    I think that I have enough tolerance for mistakes (just little bit tolerance but always better than no tolerance at all)
     
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  6. Cobbler

    Cobbler Codger bodger

    Messages:
    5,560
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    Gloucestershire UK
    Can’t you use the existing thread in the co2 bottle, then you avoid any stresses that arise from the welding. There would be no need to retest the bottle then. I’m wary of drilling & welding any pressure vessel if it can be avoided.
     
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  7. Memmeddu

    Memmeddu Member

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    Stupid thread pitch
    It's metric on the bottle and I need NPT ½" but it's not a bad idea if my local machinist has ½" NPT tap .
    He should use a piece of M30 all thread and drill and tap an hole in the centre
    I should always drill a moisture release hole in the tank itself
     
  8. the snooper

    the snooper getting older by the day

    Messages:
    20,623
    Location:
    Hull UK
    Either drill and tap it or get someone that can weld properly to do it for you, if your weld fails that will come out like a bullet
     
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  9. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

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    East Yorkshire
    Threads like this always remind me of the joke;

    A bloke jumps out an airplane, with no idea how a parachute worked. As he hurtling towards the ground, he sees another bloke sat on a gas oven...
    So he shouts over "Do you know anything about parachutes?"
    "NO!" came back to reply. "Do you know anything about Gas ovens?"
     
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  10. Capt New Member

    Messages:
    12
    Location:
    Italy
    yes
    no im not italian is that a problem ??
     
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  11. mike os

    mike os just a little insane.....

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    Nope not a problem, just curiousity
     
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  12. daleyd

    daleyd Member

    Messages:
    7,101
    Location:
    Wrexham, North Wales
    Memmeddu is also from Italy, hence the question. You may be neighbours !! (He has some good tools if you need to borrow any...):laughing::thumbup:
     
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  13. Memmeddu

    Memmeddu Member

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    No problem
    Exactly
    Well on this I would say something.
    Tools are like wives , no-one else than you can touch them .
    :D
     
  14. premmington

    premmington Member

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    2,020
    Location:
    Norfolk

    Not a stupid suggestion at all - I did this with a full size empty O2 bottle years ago.

    The issue you got using an empty gas bottle is draining the condense off. I had to mount the O2 bottle "upside down" and had a collection of Galv pipes to make a manifold with a drain port at the bottom of it. None of this was ideal...

    Air receivers have ports at the top/middle for air inlets/outlets and at the bottom for condense draining for a reason. :whistle:
     
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  15. Capt New Member

    Messages:
    12
    Location:
    Italy
    thank you for your answers
    i appreciate your explanation
    and i agreed with you
    by the way the bottle i want to use for air compressore project 8BAR MAX for hobbies paint
    blow tires
    blow dust on my garage ....

    i couldnt find a fitting thread so thas why i i used it
    also i have a fire extinguisher (9kg)
    i couldnt finde the right thread

    maybe i can measur it and help me to find the right thread online s i can buy it.....
    thank you
     
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  16. Capt New Member

    Messages:
    12
    Location:
    Italy
     
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  17. Memmeddu

    Memmeddu Member

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    2,945
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    First advice throw away that caliper
    It's hard to read because its cheap construction ,I used to have one of this but during technical school I've had to understand that's pointless , measurement instruments has to enough good because it's the base for every work and project .
    It seems to be ¾" or even a metric thread , you'll probably have a tap and die set from Lidl like I do .
    There's a thread pitch tool , which will say you the right thread
    The thread seems to be not tapered so I'd exclude NPT
    Strange but at least it's right hand so wouldn't be difficult to find
    Give me few minutes I'll search if we can figure out the exact thread pitch and if we can find a correct nipple on eBay

    Edit the gpl tank or maybe better say LPG since we are in this foreign forum is surely ¾" right hand so you should easily find it
    Buy both NPT and BSPT on eBay
    The other one is from the co2 fire extinguisher and it's surely an M30
     
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  18. Capt New Member

    Messages:
    12
    Location:
    Italy
    grazie mille provero ad andare a bricoman
    e comprero questo https://www.bricoman.it/it/nipple-ridotto-ottone-cromo-1-2-x-3-4-12091788/

    ma dovo vedere dopo se va perfetto con un raccordo f-f 1/2 di ghisa
     
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  19. Capt New Member

    Messages:
    12
    Location:
    Italy
    i have tap and die set of parkside
    but i dont know if the are npt or bsp
    and i dont know which one to use for 1/4 or 3/8 .... i didn't study this stuff
    on the manuale they show hmjusy measurment are different .......
     
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  20. Memmeddu

    Memmeddu Member

    Messages:
    2,945
    Location:
    Italia Sardegna
    Non è permesso dalle regole del forum scrivere in italiano

    Translation
    Thank you so much , I'll try to get a ¾" to ½" reduction from Bricoman.
    I have to figure out if it fits the threads ,if it'll do I'll solve the problem with a cast iron female/female extension .

    My answer it's not allowed writing in Italian on the forum.


    I'm pretty confident it will work
     
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