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  1. #1
    Join Date
    Feb 2010
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    Newnan Ga,
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    181

    Nitrogen or No Nitrogen?

    I'm trying to convince one of my guys that Nitrogen is not used for every single weld.if we pump down a system to swap a solenoid or a txv you don't have to flow nitrogen thru it. How many old schoolers out there even use nitrogen to weld?

  2. #2
    Join Date
    Jul 2007
    Location
    Virginia
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    5,916
    Quote Originally Posted by Grayline View Post
    I'm trying to convince one of my guys that Nitrogen is not used for every single weld.if we pump down a system to swap a solenoid or a txv you don't have to flow nitrogen thru it. How many old schoolers out there even use nitrogen to weld?
    I do - I do.

    Easy to hook up and cheap insurance.

    It takes very little nitrogen (especially with a flow meter- see attachment) to ensure you have no debris inside the line.
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    Instead of learning the tricks of the trade, learn the trade.

  3. #3
    Join Date
    May 2009
    Location
    Cummins, GA
    Posts
    1,561

    Nitrogen or No Nitrogen?

    Why wouldn't you flow nitrogen?

    The nitrogen displaces oxygen and prevents oxidation of the inside piping.

    I use nitrogen for any and all brazing I perform. TXV's, Reversing Valves, etc all have small mechanical parts that can easily clog or fail due to particulate from oxidation in the system.

    Back to my first question, Why wouldn't you flow nitrogen?

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    Flow nitrogen during every braze, every time.
    If more government is the answer, then it's a really stupid question.

  5. #5
    Join Date
    May 2004
    Location
    Salt Lake City/Tooele
    Posts
    2,721
    Need to hook it up anyways very soon after the fact to leak test the new connections. Why not spend a few moments and hook it up just before you the brazing starts.

  6. #6
    Join Date
    Feb 2010
    Location
    Calgary, Alberta
    Posts
    1,151
    I'm currently on a project where I'm brazing lots of 1-5/8 and 3-1/8 pipe.
    If I didn't use nitrogen on even of of those 3" fittings I'd have a fistful of oxide, and a plugged dryer on startup.

    We've gone through 8 nitro tanks, but it must be done!

    Braze a couple joints and then cut them open, you'll see why!

  7. #7
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,037
    Quote Originally Posted by Grayline View Post
    How many old schoolers out there even use nitrogen to weld?
    The same "old schoolers" that don't bother carrying a vacuum pump or don't believe or understand what a micron gauge is. These same old schoolers usually have a good tech following behind them cleaning up their messes when their "hurry up and get it done" work fails.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  8. #8
    Join Date
    Feb 2010
    Location
    Newnan Ga,
    Posts
    181
    Quote Originally Posted by Brent Ridley View Post
    Why wouldn't you flow nitrogen?

    The nitrogen displaces oxygen and prevents oxidation of the inside piping.

    I use nitrogen for any and all brazing I perform. TXV's, Reversing Valves, etc all have small mechanical parts that can easily clog or fail due to particulate from oxidation in the system.

    Back to my first question, Why wouldn't you flow nitrogen?
    Maybe I didn't explain my Situation ,We do use nitrogen on all welds major installs,swaps,piping,etc just when I do a pumpdown and quick swap of a solonoid or weld over a rub leak.
    if you only have an inch of welded surface its not gonna hurt to miss the hookup.. All others.... Compressor installs,Pipe-ins,major repairs etc.

  9. #9
    Join Date
    May 2009
    Location
    Cummins, GA
    Posts
    1,561
    Quote Originally Posted by Grayline View Post
    Maybe I didn't explain my Situation ,We do use nitrogen on all welds major installs,swaps,piping,etc just when I do a pumpdown and quick swap of a solonoid or weld over a rub leak.
    if you only have an inch of welded surface its not gonna hurt to miss the hookup.. All others.... Compressor installs,Pipe-ins,major repairs etc.
    Yes, it will hurt. Even a small braze (not weld) will create oxidation.

  10. #10
    Join Date
    Apr 2011
    Location
    SE Washington
    Posts
    559
    Always, even after 25 years
    Total Energy Management, inc

  11. #11
    Join Date
    Dec 2001
    Location
    Phoenix, Az
    Posts
    1,250
    Always. It only gets worse (oxidation) with POE oil.

  12. #12
    Join Date
    Jul 2012
    Location
    Western KY
    Posts
    1,221
    Do a test to see who is correct. Make up a couple small copper loops and braze one with nitro flowing and the other with out. Then cut them open and see what you see.

  13. #13
    Join Date
    Jan 2011
    Posts
    1,223
    Quote Originally Posted by firecontrol View Post
    The same "old schoolers" that don't bother carrying a vacuum pump or don't believe or understand what a micron gauge is. These same old schoolers usually have a good tech following behind them cleaning up their messes when their "hurry up and get it done" work fails.
    Now that is just a pile of steaming BS. To label an entire generation of hard working "do it by the book" mechanics in such a fashion proves one thing to me. You have no idea what you are talking about. Are there hack mechanics? Sure there are and they come in ALL ages.

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