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?