TIG welding copper

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I'm going to have a go at TIG welding some copper. The material will most likely be some 1/8" copper flat bar. Any suggestions for settings and technique such as tungsten diameter, amperage, DC or AC, cup size, gas flow, filler rod type and size, preheating, workpiece prep, etc. ?



Cheers,

Sean

 

[HoleshotHolset]

I thought we discussed this?! :-laf



1) Use DC...

2) Argon... a little more flow than mild steel... but a lot less than aluminum

3) 2% Thoriated tungsten... 3/32" should work fine for 1/8" workpieces

4) I used a piece of old Romex for filler rod...

5) No preheating necessary... . weld pool forms quite nicely on it's own without meltdown.

6) I cleaned off the oxidation with a wire brush before welding it... . I never tried welding copper without getting rid of the surface oxidation... but doubt that you'd have good results.



All in all - weld it as if you're doing mild steel for the most part.



Come on Sean!! You have the same machine as I do... you know that you don't have to worry about the settings too much at first... . just dive right in!



Matt

 

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Ahhhh, crap :-laf Just looking for any additional info that may help things out. We'll see what happens this weekend after a trip to the metal supply house



Sean

 

[HoleshotHolset]

You're lucky. I didn't have squat for metal supply places that were:



1) Relatively close to home

2) Willing to sell small quantities to a hobbyist

3) Open at hobbyist friendly hours - like Saturdays!



Let me know how it goes... . and start taking pictures of all this TIG work so that we can critique it.



Matt

 

[dresslered]

Now I've got to ask...

. . . what kind of machine are you guys using? Would you buy it again? Thanx,

 

[HoleshotHolset]

Sean and I both have Miller Syncrowave 180SD (digital readout) TIG/stick machines.



I absolutely love my machine... and I think Sean loves his just as much. I would recommend one in a heartbeat... .



Matt

 

[dresslered]

Thank you!

 

[HoleshotHolset]

No problem - let me know if/when you're in the market. I can point you in the direction of a few good sources of information and discounted welding stuff.



Matt

 

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Yah, it's nice to have all the suppliers I need closeby and open on Saturdays Hopefully I'll soon have some pictures. If the TIG on copper works out well, then I've got some ideas for a really cool looking piece. Only drawback is that copper stock is $$$$



dresslered, I'm really liking my machine so far. Would definitely buy it again.



Sean

 

[HoleshotHolset]

TIGging copper is like buttah! You'll love it... .



Matt

 

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Soooo... ... I had a rip at TIGing some copper today. I was able to run a couple of decent beads. However, it was by no means anywhere near as easy as steel or aluminum. The stock I was working on was some 3 x 1 1/2 x 1/8 copper bar. The main issue was the very fast thermal conductivity of copper. Example: doing a butt weld, pieces fitting nice and tight together, it takes the full output (180A) of my machine to form a pool within a few seconds. I can then travel about an inch before the entire two pieces are glowing red hot and a big hole melts ahead of the bead, even if I drastically reduce the amperage. I tried using some copper wire for filler rod and it works well and helps to pull some heat away from the weld so it doesn't burn through. Another issue is the relatively low oxidation temp of the copper. If I get the piece hot enough to form a good pool, then by the time I've made the weld, the rest of the piece has turned black. The oxidation comes off easily with a wire wheel, but that tends to scratch up the finish which I want to keep flat so I can polish it. I'm also concerned that this oxidation will contaminate and weaken the weld. It really seems that I could use some more amperage to establish a pool before the entire piece heats up.

Suggestions?



Cheers,

Sean

 

[HoleshotHolset]

Practice with soft copper tubing first... I could run good beads with that without burning through it. It's a lot cheaper than burning up a few pieces of expensive stock. You should be able to fusion weld it... . without any filler.



There must be other ways to get the black/oxidation off without using a wire brush... copper polish?



I never had to use much amperage when doing soft copper tubing...



Your copper welding experience sounds like me trying to TIG aluminum... . the workpiece is a puddle before I get a weld pool...



I don't know what to tell ya at this point besides practice, practice, practice... .



Matt

 

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I'll try some tubing and see what happens. It'll have much less mass so the thermal conductivity shouldn't be as much of an issue. Of course, there's a good chance I'll get out the oxy/acetylene torch and flux bronze rods :-laf



BTW, I got into some aluminum last night. It was 6061 flat bar 1/8 x 2. Used 3/32 pure tungsten and 3/32 5356 filler rod. Amperage about 120-150. Man, that stuff welds up SWEEEET. Gotta move quick though Oo.



Sean

 

[HoleshotHolset]

Sean: We gotta have a melding of the minds (pun intended... ) sometime on TIGging aluminum. You gave me a few pointers on PM's... . but it seems like you've got it figured out pretty well now.



Practice on the thin copper pipe and get back to us.



Matt