How to weld copper?

k0ua

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I don't have much brazing experience, but I have some TIG experience with copper. I would TIG it. Copper TIG's nice.
 

k0ua

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You can do that job in several different ways.
You could use low temp solder like a plumber does... -under 800 deg. F melting - with a mild acid flux. That can be done with any heat source from propane/air on up to Mapp or oxy/acetylene. You can use either old fashioned lead/tin soft solder or one of the newer lead free tin/cadmium types. Downside is that it is difficult to control just exactly where the solder will go and how much to use. Soldering is dependent on clean metal, good flux, and not getting things too hot. Just hot enough to flow.
And the joint won't be very strong. Basically it is just a little bit stronger than the solder itself.

If you are handy with an oxy/acetylene torch you can do that job in several other different ways.
For nicer control you can step up to an oxy/acetylene welding&brazing torch. The copper doesn't have to be as clean, the flux is often a boxax powder rather than a paste, and the filler rod can be any of a dozen types of brass (copper and zinc) , bronze (copper and tin), or either one with enough nickel or silver to make a very hard nickel-brazed joint. The jointing work can be done with beautiful control - it's what jewelers use for tiny work. And a nickel-brazed joint is stong enough to withstand hammering the finished product into shape. All a matter of practice, and you can get the rod for a couple of bucks/lb at the local welding supply shop.

Here are some examples of free-hand welding - there's some brass, bronze, and nickel brazing in these pieces, but not a drop of solder.
rScotty

That is some mighty nice work there.
 

tjkubota93

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To silver solder or braze like an ac line, you got to heat it until it glows, just hot enough to melt the rod. It will draw in on it's own. The melting point of the silver solder is just below that of the pipe.
 
  
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EddieWalker

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Appearance is critical, it has to look flawless. I'm not familiar with TIG, so to get it right, I think I will take it to a welder in town and have them do it if the client accepts my bid.

Thank you.
 

ddbackhoe

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I might have a job that will include welding, or maybe brazing, some copper. I will fold it over one inch and I need to connect the bent over part. This will be a cover that will go over a cabinet. It will be 22 mil thick, or 24 gauge. Its pure copper.

What would you do?

I might just take it to a welder and have them do it, but for such a small project, I think I can do this myself.

Thank you.

Are you covering a wooden cabinet with copper sheet?
 

Langanobob

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There are welders and there are welders. Not all are good with a torch anymore. Since appearance is important I would make sure they know what they are doing and I think I would look for someone who does artisan type welding rather than a commercial welder who does things like repair trailers. Maybe bring them a sample test piece first. Just my two cents worth since welding is such a broad field.
 

yomax4

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I'd Tig it with De-ox Copper filler rod. ( Deoxidized Copper ) Very clean and pleasant to use .
 

kenmac

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If I wasn't going to have it done with tig. I would use stay bright 8. It is stronger than regular solder.
It flows well and doesn't require as much heat as using brazing with a rod with a high silver content.
 
  
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EddieWalker

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I mailed off the bid and if I hear back from them, then I'll update the thread. It's not uncommon for people to call me to do something a little outside the norm, but rarely do I get to do them. My guess is that they have no idea what it will cost and when they see what my bid is, they change their mind and do something else.
 

crazyal

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Isn't that always the case? Usually the wife sees something and thinks it would look great. Then when she's informed that gold is $1000 an ounce she changes her mind. Too bad. I've seen a few custom copper vents over stoves that look very nice. But the people putting them in just said do it, not how much. To me copper in a kitchen looks so much nicer than stainless.
 
 
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