Tig welding of copper tubing

[chub380]

I have used pure argon with good results on copper. 300Dynasty

I set out to weld up some copper fish. I'm using .024 copper sheet and copper tubing - the soft stuff. The Miller Econotig I started with just was just too hot, it doesn't have a low enough amperage setting.

The same is true of the 175 wire feed machine. The wire feed actually worked pretty good running deoxidized copper wire, but the lowest setting just won't quite go low enough to avoid blowing through and if the feed was cranked up the wire would just pile up.

I ended up with (buying) a Dynasty 200 DX tig machine (what a jewel it is!), using #12 copper wire (scrap electrical wire) as the filler and the standard CO2/Argon gas mix. No flux, no real cleaning or prep. The gas mix makes for sort of a black carbon coating or film on the copper, but that washes right off. The straight argon is the recommended gas, but the cheaper mix seems to work just fine.

I find the copper tubing more difficult to weld than the much thinner copper sheet. About the time the copper is to welding temperature the tubing wants to collapse. Much control is needed.

I'm not sure there is a suitable wirefeed machine on the market for something like this. If there is, I'd sure like to hear which one it is.

[Nunzio1]

My neightbor has asked me if I can create a new rose trellis for them fabricated out of copper tubing. I was wondering if anyone has tried tig welding 1 inch diameter copper tubing together. I know that I can solder it- but if I could tig it this would give me better design options. I have a brand new Miller Tig Runner 250, Millermatic 251 mig, a Millermatic 130 mig and a Miller Spectrum 375 plasma torch. I asked my local welding supply house, but they could not recommend a proper filler rod other than a brazing type material. It would be cool if I could use a copper filler rod to keep the color consistant throughout the piece. Anyone have any experience with this?