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Hot Rods Was he BSing us?

Discussion in 'The Hokey Ass Message Board' started by woodiewagon46, Sep 3, 2021.

  1. woodiewagon46
    Joined: Mar 14, 2013
    Posts: 1,936

    woodiewagon46
    Member
    from New York

    This afternoon, I went to my welding supply to exchange a tank of oxygen. The guy in front of me was telling the guy at the counter that he was a welder for an aerospace company. He said that every frame they built wether it was chrome moly or aluminum they welded on two female pipe bungs. One was for an air gauge and one was for an air chuck. After they welded the frame they attached the gauge and air chuck and pressurized the frame. If the air gauge went down they new that had an incomplete weld or a pin hole. I never heard such a thing.
     
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  2. lostone
    Joined: Oct 13, 2013
    Posts: 1,794

    lostone
    Member
    from kansas

    Wouldn't surprise me. I figured they probably ran an inert gas thru it.
     
  3. gnichols
    Joined: Mar 6, 2008
    Posts: 11,019

    gnichols
    Member
    from Tampa, FL

    Whether you work on the space shuttle, jets, deep sea oil rigs or nuclear subs, there are all kinds of special welding techniques, systems and testing requirements. Those welders make BIG money.
     
  4. anthony myrick
    Joined: Sep 4, 2009
    Posts: 8,669

    anthony myrick
    Member

    I’ve did that before.
    But for cooling lines.
    I’ve also seen shielding gas pumped on the inside
     
    Last edited: Sep 3, 2021

  5. Be funny if the faulty welds were at the bungs.:D
     
  6. squirrel
    Joined: Sep 23, 2004
    Posts: 49,828

    squirrel
    Member

    that's what I was thinking, half way through the sentence....
     
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  7. anthony myrick
    Joined: Sep 4, 2009
    Posts: 8,669

    anthony myrick
    Member

    A friend of mine has a commercial sand blast cabinet. I’ve seen him hook argon up to the cabinet and tig using the gloves.
     
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  8. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,301

    jaw22w
    Member
    from Indiana

    I pressurize every gas tank I build, except I don't bother with a gauge. Soapy water in a spray bottle over all the weld joints. If you got a hole it will make a lot of bubbles.
     
  9. Mimilan
    Joined: Jun 13, 2019
    Posts: 943

    Mimilan
    Member

    Porsche gas pressurized the frames on their space frame 917 sports racers. Then had a port to measure the pressure.
    If there was a pressure drop ,they start looking for cracks
     
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  10. iagsxr
    Joined: Aug 26, 2008
    Posts: 158

    iagsxr
    Member

    I've seen a picture of an old dragster with a gauge on the frame.
     
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  11. THE FRENCHTOWN FLYER
    Joined: Jun 6, 2007
    Posts: 3,802

    THE FRENCHTOWN FLYER
    Member
    from FRENCHTOWN

    My buddy had an altered drag car chassis built by Gordie (Ohio) a number of years ago and he did the pressure gauge thing, so , yeah, no BS.
     
  12. patterg2003
    Joined: Sep 21, 2014
    Posts: 717

    patterg2003

    Not sure why they would use oxygen. I think the leak test would depend on the application. We built a 4130 chrome moly tube fuselage and some builders do check them for leaks. If the chrome moly is sealed then moisture can't work its way in to cause hidden corrosion. Some builders put a little boiled linseed in the tubes as it is an apparently an oxygen scavenger to help reduce corrosion. We used about 2 psi to test the aluminum fuel tanks we fabricated and used a balloon on one bung to see if it was deflating to indicate a leak as it was too low a pressure for a gauge. Not sure why they would use oxygen
     
  13. woodiewagon46
    Joined: Mar 14, 2013
    Posts: 1,936

    woodiewagon46
    Member
    from New York

    Well I guess he was legit, learn something every day!
     
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  14. Lepus
    Joined: Nov 18, 2016
    Posts: 345

    Lepus
    Member

    Where I work, we make a lot of equipment for use in vacuum chambers. Welded assemblies are pressurized with helium, then a helium detector is used to check for leaks. I don't weld, but I've had silver soldered parts checked that way.
     
  15. nickleone
    Joined: Jun 14, 2007
    Posts: 351

    nickleone
    Member

    He was only exchanging the O2 tank, not using it to test.
    nick
     
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  16. anthony myrick
    Joined: Sep 4, 2009
    Posts: 8,669

    anthony myrick
    Member

    Google friction welding
     
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  17. Mimilan
    Joined: Jun 13, 2019
    Posts: 943

    Mimilan
    Member

    Friction Stir welding is what we call it.
    I've seen it done in a factory where they were making Hydro-Electric generators.

    Fascinating technology!
     
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  18. WOODEYE
    Joined: Feb 21, 2010
    Posts: 358

    WOODEYE
    Member

    I had a tank fabricator that built 10,000 gallon tanks for me for several years . When the welding was complete on the cylinder and heads he would spray the welds lightly with diesel fuel from the inside. If there was any leak of any size the diesel fuel would then migrate through to the outside of the shell. Never had one single tank leak once installed out on the job site.
     
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  19. Natural gas pipelines, welded joints are all 100% X-Rayed. As a final test the line is filled with water then air pumped to 2000 Lbs. pressure to check the integrity of the welds and pipe. That is for a 1000 Lb. working pressure of the completed line. with higher working pressures comes higher testing pressures. Usually twice the working pressure of the line. Then after the water is drained off cleaning pigs are blown through to clean the interior. Periodically a "Smart Pig" will be used and can check for interior corrosion and pipe integrity. A pig catcher is placed over the exposed end of the pipe and is like a big net in a hole in the ground due to the extreme pressures pushing them through.
     
  20. gene-koning
    Joined: Oct 28, 2016
    Posts: 2,560

    gene-koning
    Member

    People in the commercial refrigeration (cooler & freezer repair) use nitrogen to pressure test for leaks. Its cheap, non-corrosive, non- explosive, and is not a limited resource gas (like helium is). After the pressure test, they can vent it off into the atmosphere without issues. A 90c.f. cylinder costs around $50 and can pressure test 4-5 large systems and can easily be carried onto the job site. Gene
     
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  21. deathrowdave
    Joined: May 27, 2014
    Posts: 2,698

    deathrowdave
    ALLIANCE MEMBER
    from NKy

    Warhorseracing , we must of been in the same business . This was my mode of operations for over 30 plus years
     
  22. choptop40
    Joined: Dec 23, 2009
    Posts: 4,018

    choptop40
    ALLIANCE MEMBER

    good tech stuff here ...frame pressurization ...cleaning pigs...who"d of thunk it...
     
  23. 1952henry
    Joined: Jan 8, 2006
    Posts: 893

    1952henry
    Member

    Believe I have read some states are considering its use in gas chambers.

    Some parts of dragline booms are pressurized. Gauge reads empty=crack. Bad crack/failed boom=very bad day.
     
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  24. jaracer
    Joined: Oct 4, 2008
    Posts: 1,224

    jaracer
    Member

    I've heard of guys doing this on sprint car and midget frames.
     
  25. Porsche did it on their racecars in the 1970's to show up any cracks that developed in the tube chassis.
     
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  26. H380
    Joined: Sep 20, 2015
    Posts: 463

    H380
    Member
    from Louisiana

    I see a boat trailer often at work that tilts the boat vertical so you do not need a wide load permit. The frame stays pressurized with 2 or 3 PSI at all times. Has a gauge up front. Lets you know instantly if you have a crack in the frame.
     
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  27. Mike VV
    Joined: Sep 28, 2010
    Posts: 2,441

    Mike VV
    Member
    from SoCal

    Depends...

    On one hand, I've worked in the Aerospace (one, world wide company) world for over 30 years in a coupla different companies.
    Have never seen that done. Even in aluminum, high pressure coolant pressure tubes for spacecraft.


    I also did some work early on for the oil field industry.
    Also, no testing in that manor.

    But, companies are different. Different restrictions.

    Mike
     
  28. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,171

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    The OP was exchanging HIS oxygen tank. The OP only said the “guy in front of him” told the story….the OP DID NOT say what transaction the storyteller was conducting.

    Reading is fundamental. So is listening, for that matter.

    Ray
     
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  29. Yes. I worked Union pipeline jobs in the 1970's into the 80's, IUOE 66. Worked as a Highway Superintendent prior to retirement working as a liaison between the State and gas companies. I was able to maintain a good working relationship due to the fact that I was able to relate to their procedures and the State requirements.
     
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  30. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,171

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Yep, nitrogen is plentiful and safe to ‘vent’……Earth’s atmosphere is 78% nitrogen…..

    Ray
     
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