Welding Tips and Tricks

I've been asked to weld some copper bus bars together to lengthen them. The bars are about 1/4" thick and apparently pure copper.

Either way, I can find out what exactly they are made of.

Can I TIG weld copper just like aluminum? If I can, what rod, anything particular I need to be aware of? Pure Argon? Argon mix? Pre-heat, etc.?

If I can't TIG weld copper, how would I go about joining two 1/4" x 3" copper bus bars together?

Thanks!

Jon

Sure can just use like 12 gauge solid wire with the insulation striped off for filler takes forever to heat up then get going

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don't know what machine you're using, but you can preheat to speed up the process

Certainly is weldable.

If you still got your PT185 then a preheat is more than likely required....But you mind find the pieces are so small it doesnt take long for the whole bar to get hot.

Like others have said a piece of Romex house wire works well or better yet a piece of the parent material for filler to get a exact match on the metallurgy.

More than likely Romex house wire is the same copper they use on the Bus Bars, but I'm just guessing.


If welding doesn't work out you could always silver solder them but a but joint might be a little weak depending on the application. If possible use a band or coupler if going the silver solder route.

I’ve used dc and pure Argon. Then I used stripped wire for filler. But it was just for a copper wear bar.
BEWARE someone will be liable if any electrical problem or damage happens. weather it was lightning or an actual fault of the weld. You may want to request that the company the work is for have an engineered document drawn up. It sounds like someone is cutting corners that probably shouldn’t be cut.

I've worked in a large motor rewinding factory. Joining thick bars together back to back happened every day with tig and argon to increase the thickness of the bars. They used high current and silver solder for deep penetration of the silver and sometimes just autogenous.

Having said that I've done tig welding of copper too. High current needed for sure. Works good.

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For the 1/4 inch bars probably set the machine for 200 amps ?? Then control with the pedal dcen pure argon acts a little like aluminum unless you can set the whole thing on a hot plate Ive used tarnex then acetone seems the more polished it is the easier it is to get clean sandable welds it can get away from you once it heat soaks welds autogenous great too similar to brass 1/4 inch is a great size to learn copper thin 1/2 inch pipes are rough !

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ekbmuts wrote:I've been asked to weld some copper bus bars together to lengthen them. The bars are about 1/4" thick and apparently pure copper.

Either way, I can find out what exactly they are made of.

Can I TIG weld copper just like aluminum? If I can, what rod, anything particular I need to be aware of? Pure Argon? Argon mix? Pre-heat, etc.?

If I can't TIG weld copper, how would I go about joining two 1/4" x 3" copper bus bars together?

Thanks!

Jon

You’ll want 250+ Amps, DCEN preferably with 75Ar/He25 mix. You should also v-groove (60deg) your joint and include a land for a PJP butt weld. PreHeating the Cu is a less desirable alternative than having the “on-demand” power being supplied from a high amperage source.

Even 1/8” Cu typically requires 180-200A when welding a fillet joint. Cu’s thermal conductivity is ~50% greater than Al’s.

Well, thanks everyone for all that! Very helpful.

I do still have that PT185, but I'm thinking that if I cut a groove and not bite off more than I can chew I might be just fine.

I don't have any AR/He mix. Only pure Ar in my shop but it sounds like the He is just to get more heat transfer into the weld.

Either way, I'm going to give this a shot tomorrow and see what happens.

And thanks for the advice on getting a drawing or at least something in writing so that my rear is covered in the event of a flap later on. Will do!

Jon

Post some pics!

This is ½" copper tubing:
I have tig'd 1" copper fittings, like they said, takes a lot of heat!

(Thermal Arc Arcmaster 185) (only one I ever used, love it!!)

Yeah - I'll post some pics of the welds once I finish them.

Hey, Cornmuse, sounds like you have a 185 amps max machine, just like I do. Did you weld that copper pipe with pure Argon or a mix or pure Helium (as I'm told some folks will to minimize heat loss/maximize heat transfer)???

JOn

Just argon, never tried anything else, I was an equipment operator - actually a grade-checker, not a welder, except in my garage.

-corne-