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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: 1,954

    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.
    tractorguy, Spoggie and stillrunners like this.
  2. lostone
    Joined: Oct 13, 2013
    Posts: 1,854

    from kansas

    Wouldn't surprise me. I figured they probably ran an inert gas thru it.
  3. gnichols
    Joined: Mar 6, 2008
    Posts: 11,042

    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: 8,913

    anthony myrick

    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: 50,199


    that's what I was thinking, half way through the sentence....
    ekimneirbo and anthony myrick like this.
  7. anthony myrick
    Joined: Sep 4, 2009
    Posts: 8,913

    anthony myrick

    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.
    fauj, wfo guy, Hnstray and 1 other person like this.
  8. jaw22w
    Joined: Mar 2, 2013
    Posts: 1,407

    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: 1,000


    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
    Mark Hinds, alfin32, Spoggie and 6 others like this.
  10. iagsxr
    Joined: Aug 26, 2008
    Posts: 159


    I've seen a picture of an old dragster with a gauge on the frame.
    Spoggie likes this.
    Joined: Jun 6, 2007
    Posts: 3,880


    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: 728


    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: 1,954

    from New York

    Well I guess he was legit, learn something every day!
    ratrodrodder and lothiandon1940 like this.
  14. Lepus
    Joined: Nov 18, 2016
    Posts: 347


    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: 352


    He was only exchanging the O2 tank, not using it to test.
    Desoto291Hemi and Fordors like this.
  16. anthony myrick
    Joined: Sep 4, 2009
    Posts: 8,913

    anthony myrick

    Google friction welding
    Mimilan likes this.
  17. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,000


    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!
    Hnstray, Deuces and anthony myrick like this.
    Joined: Feb 21, 2010
    Posts: 359


    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.
    Hnstray likes this.
  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: 2,623


    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
    Blues4U, safetythird, Hnstray and 2 others like this.
  21. deathrowdave
    Joined: May 27, 2014
    Posts: 2,743

    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: 4,085


    good tech stuff here ...frame pressurization pigs...who"d of thunk it...
  23. 1952henry
    Joined: Jan 8, 2006
    Posts: 914


    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.
    Hnstray and 41 GMC K-18 like this.
  24. jaracer
    Joined: Oct 4, 2008
    Posts: 1,306


    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.
    Mark Hinds likes this.
  26. H380
    Joined: Sep 20, 2015
    Posts: 466

    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.
    Spoggie and Hnstray like this.
  27. Mike VV
    Joined: Sep 28, 2010
    Posts: 2,476

    Mike VV
    from SoCal


    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.

  28. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,232

    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.

    ekimneirbo, alanp561, fauj and 6 others like this.
  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.
    Hnstray, 427 sleeper and Deuces like this.
  30. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,232

    from Quincy, IL

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

    ekimneirbo, Blues4U, fauj and 3 others like this.

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