Miller Electric

Welding Discussion Forums

Home » Resources » Communities » Welding Discussion Forums
 
Miller Welding Discussion Forums - Powered by vBulletin

Results 1 to 5 of 5

Thread: Copper Project

  1. #1
    Join Date
    Feb 2014
    Posts
    2

    Default Copper Project

    Hey everyone,

    Long story short I have this project going for a client who owns a large sugar house. We are building Copper manifolds that hold 14, 3/4" pipes and will have about 50psi of steam going through them to heat the sap up. The project is going very well so far but I've ran into a couple snags. To paint the picture for everyone I have bought new copper plate that I have waterjetted and bent to assemble the manifold the copper pipe we are using is older pipe from the early 90's I'm guessing. I have cut the pipe off the old manifolds that were Brazed together and have been using them in the new style manifold being built currently. I'm using a machine with plenty of AMP's so heat isn't an issue. The shielding gas is pure 100% argon, The filler material is deoxidized copper rod I bought from AirGas. the tungsten is E3 (Purple band). This issue is its not becoming air tight for some reason. The welds looks good and the penetration is great. some of the pipes will weld 90% great but then I hit a spot were I get lots of bubbling and it doesn't seem to want to melt together it almost makes an near impossible hold to fill for some reason?? Can anyone help me out with this? I've read some pipe contains oxygen that isn't meant to be welded. Maybe that's the issue?

    Thanks
    Rodney

  2. #2
    Join Date
    Mar 2011
    Location
    La
    Posts
    242

    Default

    Possible outgasing once pipe is almost completely sealed because the pipe is heating up. Blows away sheilding and molten metal. That's what came to mind. Weld up 90%, allow to completely cool then quickly weld up other 10%. Good luck, hope this helps.

    Ja
    Last edited by ja baudin; 02-02-2014 at 12:29 PM.


    Dynasty 200 DX
    Diversion 180 (FOR SALE)
    Millermatic 350P, XR-Aluma-Pro
    30A Spoolgun
    Lincoln Pro Mig 140
    Hypertherm Powermax 30
    14" Rage Evolution 360
    40 ton press brake
    Shop full of tools

  3. #3
    Join Date
    Sep 2009
    Location
    Colorado
    Posts
    202

    Default Old pipes?

    I wonder if the old pipes are part of the problem. Perhaps there is oxide in there.

    I don't typically backpurge copper, but this case might be a good application.

    I have not tried to make watertight welds in copper in years. Many years ago I had trouble with it, but I am a better welder now, with better equipment.

    For welding, you are theoretically supposed to use 102 alloy, not the common 110 alloy. The 102 has less oxygen. Not sure about pipe alloys, but that could be part of the problem.

    The Copper Deveolopment Association says:

    Seamless Copper Pipe

    Copper pipe is almost pure copper manufactured to the requirements of ASTM B 42 - Standard Specification for Seamless Copper Pipe, Standard Sizes. It may be manufactured from any of five (5) copper alloys (C10200, C10300, C10800, C12000, C12200) that all conform to the chemical composition requirements of alloys containing a minimum of 99.9% Copper (Cu) and a maximum of 0.04% Phosphorous (P).


    Richard

  4. #4
    Join Date
    Feb 2014
    Posts
    2

    Default

    To avoid warping I only weld about 1/4 of each pipe at a time to reduce the amount of heat put into the front plate of the manifold. So the heat shouldn't be the issue I wouldn't think since I let everything almost completely cool before doing the next 1/4 of each pipe.
    As for backing gas I also thought of this but not really sure how I would seal something off to add a backer. Maybe over the years some of the acids they use to clean the pan each season has affected the pipes. Weird thing is that I had this same problem yesterday when welding a 3/4" elbow to a new pipe even without using filler rod I ran into some problems with bubbling and not being able to melt the material in certain spots even at 270amps which is very hot for K copper pipe.
    I'm really thinking it is the oxygen content in the pipes/fittings.

  5. #5
    Join Date
    Apr 2013
    Posts
    13

    Default Copper Project

    It would be easier to make it out of black pipe fittings

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Warning: Non-static method PhpQuickProfiler::getMicroTime() should not be called statically in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/pqp/classes/Console.php on line 77

Warning: Non-static method PhpQuickProfiler::getMicroTime() should not be called statically in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/pqp/classes/Console.php on line 77

Warning: Non-static method PhpQuickProfiler::getMicroTime() should not be called statically in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/pqp/classes/Console.php on line 77

Warning: Non-static method PhpQuickProfiler::getMicroTime() should not be called statically in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/pqp/classes/Console.php on line 77

Warning: Non-static method PhpQuickProfiler::getMicroTime() should not be called statically in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/pqp/classes/Console.php on line 77

Warning: Non-static method PhpQuickProfiler::getMicroTime() should not be called statically in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/pqp/classes/Console.php on line 77

Warning: Non-static method PhpQuickProfiler::getMicroTime() should not be called statically in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/pqp/classes/Console.php on line 77

Warning: Function split() is deprecated in /mnt/stor3-wc1-dfw1/357822/357839/www.millerwelds.com/web/content/lib/footer.inc.php on line 82

Welding Projects

Special Offers: See the latest Miller deals and promotions.