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What's the best way to weld copper?

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  • subzero
    started a topic What's the best way to weld copper?

    What's the best way to weld copper?

    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!

  • Pat
    replied
    I have joined thicker copper using my MM210 with silicon bronze wire and 100 percent Argon. I am not all that familiar with the 304, but taking a quick look at the Miller info on it, I would say you should not have any problems. I think your machine has a lot more kick than the MM210. What are you joining the copper for? I have used the silicon bronze to join some #2 solid copper together for ground conductors. When used for this purpose, you eliminate any bad connections. One thing though, the electrician I did this for cleaned the weld area, and coated the joint with something to prevent corrosion. I have pieces of copper I joined about 6 years ago that does not show any corrosion.

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  • oldbazooka2
    replied
    Welding copper

    I want to weld 1/8 or 3/16 in copper bars. Will a Miller XMT 304 CC have enough amps?

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  • Demonknight
    replied
    welding copper

    You mentioned that it has to be strong, so i would go with the silicon-bronze filler rod. Parent metal does give the best color match but has very little strength. Also, the heat affected zone will become considerably softer due to the intense heat input required to weld the copper. I wouldn`t recommend trying to preheat either as it would be dissipated so quickly all your material would be annealed before it actually did you any good. Use a tig welder set to DC- just like you would for steel or s. steel but pay attention to detail when grinding the point on your tungsten. Most of us learned the proper way but usually just quickly spin a point back on it the quickest way we can. Make sure your grinding lines run longitudinal to the point, then grind yourself a generous flat spot to the point itself. This will get your heat into the copper quickly and concentrated. Stand on the pedal and work yourself a little circle till you get a wet puddle and go. If you back out of the heat too quickly anywhere along the weld you`ll loose your puddle and have too start it again which will just anneal more area than you want too. When you get it right the welds will look just like beautiful aluminum welds and almost as quickly. If you can get your hands on it, 75%He/25%Ar gas will make all this happen a lot quicker.
    Good luck and enjoy your project.............Dave.

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  • pavlov99
    replied
    If you are looking to use lesser amps, you can tig weld using grade III silver. It melts at way less temperature than copper. It won't be a perfect color match but it will be strong. Make sure you don't melt the base material before you start to add the Grade III. Start the arc, keep dabbing with the Grade III until it begins to flow. You'll get the hang of it in no time. If you do it right, it can look similar to an aluminum tig joint.

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  • Don52
    replied
    I was able to TIG weld 1/16" copper with my Dynasty 200 DX. I agree that a larger machine would handle larger or thicker pieces. Here is a link to my original post:

    http://www.millerwelds.com/resources...68&postcount=1

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  • bmwsid
    replied
    copper TIG

    When I was in the automotive industry, I welded over a million welds. Mostly aluminum. I tried experimenting with lots of stuff.
    Copper water pipe welds fine with a 350 miller, only had AC, as the place I worked didn't want to spend the extra $ for DC machines......I used #14 electrical wire, and it welded just like aluminum. Never needed over 200 amps.
    I also repaired a copper sink with a different machine, same wire, but with DC, and it sucked. I got it done, but it was much more difficult. I was tempted to switch to AC, but was told by someone who was supposed to know, that DC was best, and I didn't want to make it look different as it was about a $5,000 sink.

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  • lanceman73
    replied
    Copper

    Why not use silver solder and braze it? I use it all the time for copper to copper, copper to steel, and copper to brass. It's strong on withstands temperature changes. It won't be good for sheet metal. My friend works for a flashing manufacturer and they use plumbing solder or tig with copper or brass rod.
    Lance
    Last edited by lanceman73; 09-16-2008, 09:30 PM.

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  • Bodybagger
    replied
    I've done this

    When I got my first TIG welder I did exactly what you are inquiring about. I was just experimenting, welding razorblades together and such. I thought I'd try welding 1/2" copper pipes. I melted the first one down, but then I got the hang of it. It needs to get very hot, nearly to the point of melting the copper, then you hit for a second and it welds. The puddle doesn't last long enough to really see it. The whole tube just oops out before that happens.

    That welder was a $200 (on sale) Harbor Freight 130A scratch start inverter tig welder. It doesn't take a lot of heat to weld 1/2" type L copper pipe.

    Yes, you need a lot of heat to weld copper sheet because every inch the heat travels, it gets an inch further away from the arc... but on small diameter pipe, when the heat travels an inch - well, it's almost right back where it started. Or in more thermodynamic terms, it cant utilize it's thermal mass as efficiently as a sheet because it can only move up and down the axis of the pipe instead of radiating outward in all directions on a sheet.

    I found the best way to do it was to make an autogenous weld by melting the edge of the fittings over and onto the pipe. I held the torch with the right hand and used my left hand to rotate the amperage control like a "poor man's pulse".

    The results were very aesthetically pleasing. The welds were virtually indistinguishable from the rest of the pipe. I showed my sister the completed fittings and she seemed to think they'd make excellent drug paraphernalia. I didn't set out to make a dope pipe, so I broke it and chucked it in the scrap pile, otherwise I'd show you pictures.

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  • kelbualy
    replied
    [QUOTE= only certian grades of copper are weldable, although most are able to be brazed, soldered etc.... You would be prety limited on the thikness. We push our sync. 350's at work nearly to the breaking point on the copper/nickle stuff we do.

    How can you find out what grade is weldable? I never had any problems with a torch, why with a TIG?

    Also I am interested in buying a Tig for welding copper on copper. What about the Dynasty 300 DX. I think the 200 DX just doesn't have enough amp power to puddle it. Unless you go to Helium/Argon mix??

    Any imput would be great, thanks,

    Kim

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  • weldress
    replied
    welding copper to copper

    If it is decorative, Oxy-acetylene does the job...parent metal as filler....I do it all the time....practice makes perfect....weldress

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  • Aerometalworker
    replied
    Originally posted by subzero View Post
    Looks like I will for sure start out with OA and deoxidized copper welding rod. I will keep one eye open for a TIG while I'm at it (depending on my results).
    From my research, the copper sheet metal shouldnt be a problem with OA. What about plumbing pipes? Just looking at the 1/2" & 3/4" rigid copper pipe at Home Depot.

    Are there any good sources of info online for welding copper with OA?

    Once again, I want to thank everyone for their input! Lots of good info.
    SZ,
    The plumbing type pipe welds just fine, in fact we buy ours from home depot for engineering projects. Kent White has some copper info at his site in the technical area, He has a good booklet on the subject as well. Otherwise the guys at www.metalmeet.com in the forums talk of welding copper as well.
    Good Luck!
    -Aaron

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  • subzero
    replied
    Originally posted by Anti-GMAW View Post
    Keep in mind that only certian grades of copper are weldable, although most are able to be brazed, soldered etc.... The econo tig and the 200 wont have the power for any real welding on copper. You would be prety limited on the thikness. We push our sync. 350's at work nearly to the breaking point on the copper/nickle stuff we do.
    Looks like I will for sure start out with OA and deoxidized copper welding rod. I will keep one eye open for a TIG while I'm at it (depending on my results).
    From my research, the copper sheet metal shouldnt be a problem with OA. What about plumbing pipes? Just looking at the 1/2" & 3/4" rigid copper pipe at Home Depot.

    Are there any good sources of info online for welding copper with OA?

    Once again, I want to thank everyone for their input! Lots of good info.

    Leave a comment:


  • fun4now
    replied
    cool that would be verry helpfull.
    like i said i think O/A and most likely brazing is going to be the best fit.

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  • Fat-Fab.com
    replied
    Originally posted by fun4now View Post
    you have to keep in mind he is not doing structural weld but rather art work requireing only that it atach for decoration, not to hold a load. so wile all the advice is good it dose not all fit his need.
    I doubt that any power source hooked into a 1 phase 220 outlet would eaven get a puddle going on standard copper pipe say 1/2" id.

    Ill give it a try tomorrow on my dynasty 200 and let you know how I do.

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