What's the best way to weld copper?

[TS-Off-Road]

It's bronze, so it won't match the copper, but it will stick it together. It also takes less heat to mig braze, so a MM175 should be up to the task. If he needs the welded area to match, well, like you all suggested - TIG.

[subzero]

I doubt the cabability of the 175 for what your needing.
If you dont have a TIG, gas weld it using copper filler and flux, its used a lot for ornamental copper work and copper pressure vessels.
www.tinmantech.com is a good source for materials and further information.
-Aaron

I appreciate the advice, I have checked out the site and believe I will begin by trying my projects w/ OA torch.

I never object to having too many tools, so I have another question. If you were going to be welding copper among other things, "Which TIG would be your choice, while trying to stay budget minded?".
I saw a used Miller Econotig for $1100obo, also a few Syncrowave 200's pop up from time to time. I know some of you guys say crank up the amps. What amp range is adequate?

I sincerely appreciate your help!

[Anti-GMAW]

Keep in mind that only certian grades of copper are weldable, although most are able to be brazed, soldered etc.... The econo tig and the 200 wont have the power for any real welding on copper. You would be prety limited on the thikness. We push our sync. 350's at work nearly to the breaking point on the copper/nickle stuff we do.

[WELD 15]

What wall thickness on the pipe?
Silver brazing works fine -a 45% or a 50N flow very nice, although it is expensive - sold by the ounce if that tells ya anything - or you could use a 15% sil/phos as well.

Welding copper - again thickness matters - 250 amp Miller Syncrowave would be my machine of choice. Set on AC, Hi-Freq continous, pure tungsten, sil/bronze as your filler material and 100% Argon for shielding gas.

[Aerometalworker]

I appreciate the advice, I have checked out the site and believe I will begin by trying my projects w/ OA torch.

I never object to having too many tools, so I have another question. If you were going to be welding copper among other things, "Which TIG would be your choice, while trying to stay budget minded?".
I saw a used Miller Econotig for $1100obo, also a few Syncrowave 200's pop up from time to time. I know some of you guys say crank up the amps. What amp range is adequate?

I sincerely appreciate your help!

Good luck with the copper welding, Ive used it a bit for some reproduction work. Welding with the torch really goes quite well. Having a flame temp thats hotter then a TIG arc helps as well, you will find it nice for making some beautiful welds. Also fluxing the back of the part as well makes the weld bead almost nicer on the backside, something a TIG cant without a backpurge. If you want to TIG in the futute, I find my dyn 300 is almost as capable as my small aircraft style torch.

-Aaron

[MAC702]

GTAW: typically 11000 degrees F
OFW-A: typically 6000 degrees F

Those are ballparks, and they vary with many factors, but I don't see how you can say the O/A is hotter than TIG. Or were you saying something else?

Solarflux is available for protecting the back of a TIG weld on things like stainless. Does it work for copper, too? Might be worth checking into.

[Aerometalworker]

GTAW: typically 11000 degrees F
OFW-A: typically 6000 degrees F

Those are ballparks, and they vary with many factors, but I don't see how you can say the O/A is hotter than TIG. Or were you saying something else?

Solarflux is available for protecting the back of a TIG weld on things like stainless. Does it work for copper, too? Might be worth checking into.

MAC,
your correct I should have been more specific. I should have said the average temperature of the cross section of the arc/flame. The TIG arc temp can be quite high in the center, but cools off a lot in the outer envelope of the arc. I should have said somethin likeenergy imput. Yes there is a copper flux, its been around for years before TIG. I think you can get it from allstate, as well as kent white. As far as your listed Tig arc temp, If you hold a gap of about 10mm at 100 amps ( with the tungsten as the cathode) the center of the arc at the tip of the tungsten will be about 20,000K, and about 6,000K at the work (anode). Note that this does not mean that the tungsten is getting more heat, this is where we get into cathode jets, heat flux input to annode and all sorts of things in the arc plasma. Simplified, the OA flame has a lot of energy input for its physical flame size, and works perfectly for copper, and in some ways better then TIG, just one of those things thats hard to beat no matter how many red and blue machines we throw at it.

-Aaron

[fun4now]

he is working with verry thin copper, the pipe is under 1/8" or there abouts.
i would skip the econotig but the syncro200 would be a decent TIG for your uses. a syncro180 would also work and most likely be findable at a decent price if you can find one near enough shipping dose not kill you. a new syncro 200 compleat ready to weld package is about $1900 shipping included so dont get caught up in a bidding war and go to high.
if you want to go with an inverter for lower imput power option or smaller size the TA-185's are about $2000 ready to weld, the dyn200 is about $3000 ready to weld both including shipping.
although i think O/A is still the best starting point as it should handle all your needs with a lil practis. add a TIG later when you feel the need or want if thats the case, but the O/A setup is verry versatal and lends its self to art quite well once you start to lern all its abilitys.

[Fat-Fab.com]

MAC,
your correct I should have been more specific. I should have said the average temperature of the cross section of the arc/flame. The TIG arc temp can be quite high in the center, but cools off a lot in the outer envelope of the arc. I should have said somethin likeenergy imput. Yes there is a copper flux, its been around for years before TIG. I think you can get it from allstate, as well as kent white. As far as your listed Tig arc temp, If you hold a gap of about 10mm at 100 amps ( with the tungsten as the cathode) the center of the arc at the tip of the tungsten will be about 20,000K, and about 6,000K at the work (anode). Note that this does not mean that the tungsten is getting more heat, this is where we get into cathode jets, heat flux input to annode and all sorts of things in the arc plasma. Simplified, the OA flame has a lot of energy input for its physical flame size, and works perfectly for copper, and in some ways better then TIG, just one of those things thats hard to beat no matter how many red and blue machines we throw at it.

-Aaron

This discussion is why when doing weld procedure qualification records we record the interpass temp at various points starting at the center of the weld moving to the toe and then calculate the total Joules of energy input.


Not that I can realy talk to this subject.



As to welding copper with GTAW the stuff I have welded required pushing a SW350 to the max using 1/4" tungsten and that was for .125 thick sheet copper. The filler was cut from the same sheet. I had much better result when the company sprang for a SW750and a 1000amp torch. It made welding 1"Inconel a lot easer as well.


So with out many thousands of dollars and three phase power i think you are limited to braise or silver solder and I would opt for the silver as with the right joint you could hide all the silver.

[fun4now]

you have to keep in mind he is not doing structural weld but rather art work requireing only that it atach for decoration, not to hold a load. so wile all the advice is good it dose not all fit his need.