Copper Welding

my experience with welding copper always anneals the area that is welded because of the heat involved. Laser welding might reduce the annealed area since the area is concentrated

Silver solder, or 95/5 solder may do what you need, otherwise look into electron beam welding. Companies I have worked for have used that for copper and copper alloys with great success. the applications involved the conductance of both electricity and heat, in addition to mechanical strength.

There is a cold welding process with pressure dies. I am using some machines from Huestis and they works fine.

"Cold pressure welding is a method for permanently joining nonferrous metals and their alloys without using heat, fillers or fluxes. Round wire or rod sections, dissimilar materials, and materials of different sizes can all be welded with PMW's proven cold welding technology. The cold welder produces a weld that is stronger than the parent material without sacrificing electrical integrity. Huestis Industrial distributes PWM's complete line of welders and dies"

Jaime

UPTO 8g -means max 5mm dia ?

Minimum dia -- how many mm?

Please explain"Ceramic Sleeve"-where does that come from?-can you sketch

Depending on your application, there is a system available called "Cad Weld." It is generally used for grounding purposes. It is a mixture of gunpowder and metal that you pour into a ceramic mold. (Or preformed steel molds.) You light it and it does the rest. It's fun to work with. I found this site after a quick search which may answer some questions for you. http://www.mikeholt.com/code_forum/showthread.php?t=58136

You do not need a regular Tig Welding Machine--but you can use one for the 2.0---2,5 mm dia. There are so many machine types I can refer you to.

For Dia 1.6 and below you still need a shield gas -say Argon, but butt-weld with Capacitor charged stored energy + anElectronic switch will work best. A do-it-yourself setup with a variac+rectifier+charging Capacitor---switched with aThyristor is the best. Maybe there are commercial models already. Wire trade journals should be referred to

Jaime's suggested Cold weld machines will be ideal--if you can get the drawing strength needed.

Sorry, somehow I didn't see the wire size you listed on the bottom of your question.

Years ago I worked on a copper foil mill that made strips for radiators.

To join a new roll to an old they cold "welded" the foil together with 2 pressure dies excited with an ultrasonic transducer. The foils were inseparable and looked genuinely welded.

He wants Butt Weld --to draw continuously.

I seem to have missed the issue of wanting to further draw the wire in the original post.

I was fascinated by the process of using ultrasound and pressure.

You are correct that the foils were a lap joint.

However I have often found the transfer of technology from one process to another can sometimes have interesting results. The techniques for joining non-ferrous materials with pressure, or heat , or solder etc are consistent.

With the same thought process it is interesting to note that aluminum foil is rolled to its final thickness as a double thickness and then separated onto a top and bottom rewinder. Interesting in that you can cold weld with pressure yet the process here rolls it and easily separates the foils. There are often many issues involved with making good welds, cleanliness often being essential.

Has anyone experience with cold [pressure] welding of Copper [ETP] rod, diameters in the area of 0.300"?

Specifically, am curious as to why rod from one supplier would perform worse than another's, breaking at the weld during the first few dies in the rod breakdown machine?

ETP Copper from two suppliers can be cold welded and ran with a minimum of breaks, whereas the same spec material from another supplier will experience rod breaks in the first part of the breakdown machine - no other changes are made, besides switching material.

Thanks!

This problem of yours(dia 13mm) is so different from elabd110's max 2.5mm.

You will do best with TIG+Argon buttweld.The Heating and annealing during a few minutes in flowing Argon will homogenize properties of parents' . Won't break any more.

Want machines?

______________________

"Begin with the end in mind." -- Stephen Covey

Yes, please - what machines would you then recommend? Thanks. Still curious though as to what would make rod that is basically the same material from different suppliers behave so differently. One fact that did not mention above is that the material from the one vendor who's product is failing in the cold weld process is somewhat softer than the others. How much difference would that make? Is there any other items that would cause this material to act different?

A MIG/MAG 100Amp machine***

with filler wire of OFHC copper

Just keep the gas flowing for a few more seconds after the 2mm Butt gap is filled in about 30 seconds.

The MIG filling of the Butt gap should be done in a SS U mould which you DIY from any 1mm+ SS strip in your shop.

Going back to your fundamental question ---why the same metal becomes so different in properties---well ,this takes us to the depths of Recrystallization/ Annealing/grain sizes.

We cannot solve all the atomic problems,but we can soon enough find optimum solutions /tricks in the shop floor to keep us going. That will be post MIG gas flow time setting.

Now to the machine***

Please go thru the Instruction Manual of a small MIG/MAG machine:

MIG G RAN...doc (164.7 KB)

And how do you get the 100Amp machine?

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