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merf23
08-07-2003, 06:46 PM
Can copper be TIG welded? If not, what is the best way to attach two pieces?
I am thinking of making a hood over the frot of the fireplace and want it to look nice.

Evan
08-07-2003, 07:03 PM
I built a large copper hood (6' tall) for a resturant fireplace once. I used copper pan head rivets and it looked very nice. Rub a little liver of sulfer on the rivets and then polish it off to get an antique effect around the rivets. A bit of hammer work looks good too.

Oh yeah, anneal the rivets first if you use them.

[This message has been edited by Evan (edited 08-07-2003).]

Cass
08-07-2003, 07:13 PM
You can TIG weld copper sheet with no special technique except that you will be surprised at how much current it takes because of the extraordinary thermal conductivity of copper. Thin sheet is pretty easy. I once built some fender decorations for a giant old car someone wanted to restore the original part was made of copper which was nickel and chrome plated. The copper was about 0.040" thick and it was straight forward to weld it with TIG and copper wire. Another time I experimented with welding 1/2" thick copper buss bars and we found that small pieces could be welded ok with a copper stick rod from Eutectic company and with the mother of all TIG torches. When we went to big pieces, even at 800 amps of weld current we couldn't put enough heat in to not have a cold joint. We silver soldered using the big TIG torch as a heat source. Days of running 800 amps while living under a lot of leather and with a big fan on your back. Sheet copper no problem.

wierdscience
08-07-2003, 08:13 PM
Cass,I have heard of welding copper with TIG but never tried it,do you use straight dc and argon?or is a special setup required?

Cass
08-07-2003, 09:15 PM
DC and Argon, nothing special, very similar to aluminum but without the problem of refractory oxide that you have with aluminum.

Randolph
08-07-2003, 09:16 PM
I have welded copper with TIG (GTAW) and Cass is correct. It takes a LOT of heat to weld anything except small or thin sections. Recommended procedure is DCEN for current settings. 100% Argon or a 75% Helium/25%Argon mix for shielding gas and 1 or 2% Thoriated tungsten. I was welding 3/8" x 1" copper bar for a customer and welded at 400 Amps because that is all I had.

ibewgypsie
08-08-2003, 01:23 AM
Not only can you tig it, At TVA I have seen them mig it. It does take a higher power level thou.

Copper bus bar off the generators. To the liquid cooled tubing they use for bus.

Ohh yeah, make sure you have plenty of ventilation, it leaves a bad taste in your mouth.

[This message has been edited by ibewgypsie (edited 08-08-2003).]