What's the best way to weld copper?

[subzero]

I have a few projects planned where I will need to weld copper to copper. Some copper pipe, and some copper sheet metal. These projects will need strong welds, I also dont want a brass look where the weld joints are, like sweating in plumbing. I am looking into patina or burnt copper finish when I am done, so it has to look good, I can grind down a weld with no problems if the process doesn't add another metal type that will show through and ruin the look I am going for. I appreciate any and all comments!

[Fat-Fab.com]

GTAW and lots of amps and for filler use the same material as the parent material

[fun4now]

yep TIG it, just remember it sucks up the heat so you will need big amps for any thing thick. how thick is the copper you intend to do?? if its realythick you might need to go to plasma welding it.

[subzero]

One project is sheet metal, haven't bought it yet so don't have the thickness. The other is copper plumbing pipe.

I have access to a Miller 175 Mig. Is there any way to use that for this project?
I saw on mw.com where this welder is capable of copper welding. Someone told me that I could weld copper w/ the 175, but would need a spool gun to do it.

Thanks for the input!

[Aerometalworker]

Originally Posted by subzero

One project is sheet metal, haven't bought it yet so don't have the thickness. The other is copper plumbing pipe.

I have access to a Miller 175 Mig. Is there any way to use that for this project?
I saw on mw.com where this welder is capable of copper welding. Someone told me that I could weld copper w/ the 175, but would need a spool gun to do it.

Thanks for the input!

I doubt the cabability of the 175 for what your needing.
If you dont have a TIG, gas weld it using copper filler and flux, its used a lot for ornamental copper work and copper pressure vessels.
www.tinmantech.com is a good source for materials and further information.
-Aaron

[MAC702]

GTAW with a piece of the actual parent metal to use for filler is the best way to achieve the perfect finish you are looking for.

[phila.renewal]

TIG it DCEN with deoxidized copper filler. Don't use bare electrical wire or plain copper -- the welds will come out like crap. Deoxidized copper filler is not hard to find.

I confess that I have never done it . . . at least successfully . . . but I have seen it done and it works.

Also, copper needs lots of heat. Don't be shy with the amps.

Good luck with it and post pics.

[dabeldesign]

I like silica-bronze filler to Tig weld copper. It's easy, gives you a clean finish, and it's strong. I'm not sure about patina finishes on it though.
But then again, it sounds like you don't have a tig welder. O/A torch would be my next choice...

[TS-Off-Road]

Originally Posted by subzero

One project is sheet metal, haven't bought it yet so don't have the thickness. The other is copper plumbing pipe.

I have access to a Miller 175 Mig. Is there any way to use that for this project?
I saw on mw.com where this welder is capable of copper welding. Someone told me that I could weld copper w/ the 175, but would need a spool gun to do it.

Thanks for the input!

You can get silicon-bronze mig wire and with 100% argon you can mig braze it. Daytona Mig has 2lb spools of .030 s/b wire for around $30, 10lbs for $140.
Not sure if you need a spool gun to use it like you do with Al.

[MAC702]

Originally Posted by TS-Off-Road

You can get silicon-bronze mig wire and with 100% argon you can mig braze it. Daytona Mig has 2lb spools of .030 s/b wire for around $30, 10lbs for $140.
Not sure if you need a spool gun to use it like you do with Al.

How will the final finish turn out compared to the properties of the parent weldment?

You shouldn't need a spoolgun. Silicon Bronze wire is much stiffer than aluminum.