welding copper?

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Old 06-21-05, 09:37 AM
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Question welding copper?

was wanting to know how to weld copper to copper? besides sodering or braising. can copper be welded with a tig and copper filler rod?
i am looking to do some small art type projects with copper and didnt want the soder to show when joining .is this able to be done?
 
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Old 06-21-05, 12:00 PM
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http://www.brazing.com/techguide/pro...er_welding.asp

Google search for "copper welding"

Which copper alloy are you attempting to join?
 
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Old 06-22-05, 05:55 AM
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have not got that far as to know what alloy i am planning on doing art craft type stuff using thin copper sheet metal
 
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Old 06-30-05, 06:09 AM
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The alloy is not really that important. You can weld Cu to Cu or practically any other metal you want, so long as it does not undergo its own exothermic joining(which will completely deform your pieces). The setback is, that if you pick alloys or metals that form intermetallics for that atomic/weight percent, or have a vast difference in solid to liquid at the composition/temp, it will form a very brittle weld. however it requires a special kind of TIG. You could do it with regular tig, provided you set the gas flow really high and your post flow to 5 or so seconds, and weld tiny little area's (that the gas covers) each time. The issue here, is the oxidation by atmosphere your Cu will undergo with heating, all while keeping in mind that Cu is a great thermal conductor. So... you have to apply a lot of heat, really fast, else the heat will just move to everywhere else, negating your protective field of gas, and the piece will turn black.

There is a special kind of TIG that involves working in an inert gas, with any old arc welder w/ stinger (or a power supply with HF start) and thoriated tungsten rod. While you can make these systems pretty cheaply when you know what your doing, they are often more hassle than they are worth, and expensive to maintain.
 
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Old 06-30-05, 01:31 PM
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thanks for the reply but all sounds to complicated i think i will stick to soder and clean up what i dont want to show or try and get really good so i dont get any where i dont want it.
 
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Old 07-11-05, 12:06 AM
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Copper sulfate may be used to change solder to a copper colour. Comes in crystal or liquid form, available at jeweller's suppliers (or unexpected sources - probably cheaper) very toxic, brush it on.

Alternately - and this isn't so difficult as it may sound - the entire piece may be electroplated with copper on the kitchen counter.
 
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Old 07-13-05, 08:25 AM
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ok now you have peeked my intrest?how do you copper plate in the kitchen?
 
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Old 07-13-05, 12:25 PM
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You can buy a brush plating kit like this one, or a deluxe immersion kit like this. That second kit includes a lot of things you don't really need for immersion electrical deposition, though, and is bulked up with everyday items like plastic tubs and hunks of sacrificial copper. Yet it doesn't include a power supply?!

You may already have all the equipment and chemicals necessary for bath or brush electroplating, around the house and garage, and you certainly have most of them.

About electroplating.

Classroom electroplating experiment.

Note the "substitutions":
1. Copper(II) sulfate pentahydrate is available from garden supply stores as root eater.
2. Sulfuric acid is available from auto supply stores as battery acid.
3. A battery charger or 9-V battery may be substituted for the power supply.

I use an old computer power supply, but any transformer that came with an answering machine, etc. is fine so long as it gives you something like 6-12 volts DC.

Obviously the chemicals involved are nasty ones, but since you're OK with TIG welding I needn't warn you.

There are also chemical deposition touch-up pens, used mainly by jewellers. The plating isn't so thick.
 
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Old 07-14-05, 07:34 AM
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Talking

wow this is great i looked over the links you gave and think the brush would be perfect for what i am doing and very reasonable.have you ever used this?
i was thinking about brazing instead of sodering might be stronger will the elecro plate work for that also?thanks agin for all your help.
Dave.
 

Last edited by dbblackburn; 07-14-05 at 07:35 AM. Reason: spelling
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Old 07-14-05, 12:59 PM
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I've just tried the bath electroplating, and only as a curiosity. I guess it would work on brazed joints, since the plating metal deposits on anything electrically conductive. You can even plate plant leaves, with some preparation.

The brush looks simpler, but it's really the same setup as a bath. Only difference is the solution is contained in a sponge or "bandage", not a tub. You can "dip" just certain areas in solution. You may grow tired of sitting there working the brush around - I really don't know how long it takes to get an adequate plate this way, and hope it's quicker than the bath method. You might also see a faint colour difference between the plated and non-plated areas. Just my guess.

Personally, I would use full immersion in a bath, plate everything. Leave overnight if necessary. If your pieces are very large, and you've making just a few, that would be impractical.

The deposition will be thicker where the current path is strongest through the electrolyte solution. It won't go around corners much, and anything pointing out at the anode will steal a lot of metal (short circuit). The good news is, an anode can be any shape whatsoever; you can use convoluted forms of solid copper wire poking into nooks, for example.

I adjust current simply by tweaking the gaps between anode and cathode, no gadgets. You can tell by streams of bubbles rising off the cathode how quickly deposition is taking place, and where.
 
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