Welding copper.

[motolife313]

Lol. That is a nice looking weld. When I was playing with 1/16 copper and about .080 brass back to back, the copper took a increadble 116 Amps or so to puddle a flat piece of 1/16. And the brass took about 70 amps on AC and smoked a bunch. I bet you got a good size puddle going instantly with that many amps

[piggled]

That brass welded above don't take jack for amps to weld! Half as much as copper. The op is probably so lost with all these Coments saying you need a army to weld copper. Just rent a machine and see for yourself. That's the only way to get something done in this world. 250 amp machine and preheat. You will want to start on the outside edge of your miter cut. That way it will take the least amps to get a puddle started. The inside of the miter will take the most but when it gets red hot you wont need much over 200 amps

Thank you! That's the advice I was looking for. I appreciate it!

[motolife313]

It wouldn't hurt too go even more to 300 amps that way you can get the puddle going right away almost. But you would not need it red hot then 300 amps. 300 to start it then back off as needed. Your problem way be getting the right torch tho. Maybe xmt 304 welder.

[xryan]

I'll just leave this here for you so you won't make the same mistake.

Simple Definition of constructive

: helping to develop or improve something : helpful to someone instead of upsetting and negative

Good enough. I'll man up and apologize. I truly do not mean to be critical or condescending. I guess after hearing hundreds of times from those who "yeah I can weld" gets old when they ask you to fix the pile of poo they made and polish it into a diamond, after you told them how to do it right. That is much less than the things I've seen where someone who doesn't belong even putting a helmet on welding things that cause harm to others. I'm sure you can see the comment "don't think it needs weld depth" etc, leads where it does. You asked for pointers on welding copper: my advise from years of experience is LOTS of preheat, more amps than a hobby TIG provides and PRACTICE. It's totally different than steel and more difficult than aluminum. I hope your project turns out well. Good luck.

[DSW]

Part of the comments has to do with the complexity of tig welding. With Mig welding, I can take pretty much any new student and have them sticking two pieces of metal together 1st night of class, and by the end of the 48 hours of a semester, they can be a pretty fair mig welder if they apply themselves. Same does not go for tig.

It can often take them 15-20 hours just to get the basics down and adding filler semi consistently. By the end of class many can do basic lap joints in the flat position. That is on steel where the puddle is easy to control. Even with all my years teaching basic tig I doubt I'd want to dive head 1st into a project on copper and expect to make furniture quality welds right away. It might not be too bad if I had plenty of cheap scrap to play with 1st, but at the cost of materials you are talking, I'd balk just at what practice alone would cost me to get to the point I'd be comfortable taking on the job.

I think I'd rather take a stab at flying the 747 mentioned earlier with no experience. At least with the newer ones I bet I could read enough in a few hours to let the electronics fly the plane from A to B.

[Silicon-based]

I have been working with some scrap #2 solid copper wire, splitting it, annealing it and hammering it into shapes like crosses. Have not tried to solder anything yet although I have done a fair amount of welding mild steel with O/A. I have also sweated a ton of copper pipe but I don't guess that counts.

At the risk of hijacking this thread, for what you're doing I use Harris Stay-silv 15 aka Sil-phos. It is meant for fillets and larger gaps, and has a darker color than most silver solders, meaning a better color match for copper. Mainly used for soldering copper tubes in refrigeration equipment, but also very useful for metal sculpture. Use standard white flux for copper.

To the OP, while I like the look of copper as much as anyone, I don't think it's the right material for the stand you are trying to make. It has a low strength-to-weight ratio as well as the welding difficulties being discussed here. I hope you can convince your client to go with another material, but I wish you best of luck however you decide to proceed.

John

[Insaneride]

At the risk of hijacking this thread, for what you're doing I use Harris Stay-silv 15 aka Sil-phos. It is meant for fillets and larger gaps, and has a darker color than most silver solders, meaning a better color match for copper. Mainly used for soldering copper tubes in refrigeration equipment, but also very useful for metal sculpture. Use standard white flux for copper.

To the OP, while I like the look of copper as much as anyone, I don't think it's the right material for the stand you are trying to make. It has a low strength-to-weight ratio as well as the welding difficulties being discussed here. I hope you can convince your client to go with another material, but I wish you best of luck however you decide to proceed.

John

Makes good sense. I can braze silver solder with MAPP/white flux and Pb:Sn with acid flux or rosin and propane but I dont see the structual benefit.

[92dlxman]

At the risk of hijacking this thread, for what you're doing I use Harris Stay-silv 15 aka Sil-phos. It is meant for fillets and larger gaps, and has a darker color than most silver solders, meaning a better color match for copper. Mainly used for soldering copper tubes in refrigeration equipment, but also very useful for metal sculpture. Use standard white flux for copper.

To the OP, while I like the look of copper as much as anyone, I don't think it's the right material for the stand you are trying to make. It has a low strength-to-weight ratio as well as the welding difficulties being discussed here. I hope you can convince your client to go with another material, but I wish you best of luck however you decide to proceed. John

i use nothing but harris 15 when brazing, and it will leave a very dark finish unless you "rainbow" the joint with post-heat. it does not require flux. there is no better brazing rod, but, it will not color match well.

i have tig-brazed with "blockade" with decent results, but still no color match.

an old mentor of mine went through the color match problem building high dollar gates (the guy makes roses out of copper sheet), and found nothing better than welding with copper rod.

harris 15 will hold, and be easy to work with, but, it will always be visible unless you hide it with the "rainbow" finish.

[Maximo]

Honestly, I think you should just do it in steel, then cooper plate it. Copper plating at home is relatively easy. You can find several videos on Youtube explaining how to do it. You need a solution of distilled water with Copper Sulfide (you can buy online), or table salt with muriatic acid, a piece of copper wire/tube, and a car battery charger, as well as a container large enough to submerge the piece you want to plate.

Make sure you grind it nice and have no oils and impurities on it. After you start the process in 10 minutes you have a copper plated piece without the complexities of tig welding with an industrial machine.

[thegary]

I would drill holes and use steel dowels that are hidden on the finished product then silver braze the joints. It would be similar to working with wood and glueing. Get some silver braze flux and coat everything including the steel dowels with it put it together put clamps on it to pull the joint together and use oxy acetylene to heat. Practice a few loints before you try the real thing. When you are done you will see a braze line thinner than a pencil line at each joint.The line would be very hard to see unless you got right down by the joint with your eye. From 2-3 ft away it would be invisible. Any over flow can be polished off .
They make sliver braze ribbon that is 3/4 wide and .010 thick that you could sandwitch in the joint and when heated it will melt and flow and the clamps would pull it together as the ribbon melted. With silver braze the tighter the joint the stronger it is. The dowl will make the joint srong if some kid were to stand on the horizontal bar. Be ware that copper is soft and will not take a lot to bend that bar.
No matter how you do it do not quench the joints when done or the copper will anneal and really get soft.

[Tim9]

Oh yeah!
Plug in the numbers.
https://www.millerwelds.com/resource...ing-calculator

Wow...The calc only goes up to 1/2" copper....And Cep is right about the amps.

Tungsten Electrode Diameter:
3/16" (4.8 mm) or 1/4" (6.4 mm)

Historically, 2% thoriated tungsten (red band) prepared with a pointed end has been used. Today more people are switching to 2% ceriated or 1.5% lanthanum (gold band) due to their superior performance in most applications

Torch Cup Orifice Diameter:
1/2 - 5/8" (12.7 - 15.9 mm)

Use ceramic cup when welding with less than 250 amps. Use water-cooled torch when welding with more than 200 amps.

Filler Metal Diameter:
1/4" (6.4 mm)

Polarity:
DCEN (straight polarity)

Amperage Range:
375-525


Gas:
Helium

Gas Flow Rate:
40 cfh or 15 psi


Welding Speed:
Requires 3 passes, preheat 500� F. (Welding speed for multiple passes cannot be accurately predicted.)

[teh603]

Some of those calcs give weird results when you're doing multiple passes. They seem to be coded for a "one and done" approach." In this case, however, it's probably bang on. If nothing else you have a starting point.

For something that hot, though, wouldn't dual tungsten start to be attractive if you can get the necessary rig?

Part of the comments has to do with the complexity of tig welding. With Mig welding, I can take pretty much any new student and have them sticking two pieces of metal together 1st night of class, and by the end of the 48 hours of a semester, they can be a pretty fair mig welder if they apply themselves. Same does not go for tig.

It can often take them 15-20 hours just to get the basics down and adding filler semi consistently. By the end of class many can do basic lap joints in the flat position. That is on steel where the puddle is easy to control. Even with all my years teaching basic tig I doubt I'd want to dive head 1st into a project on copper and expect to make furniture quality welds right away. It might not be too bad if I had plenty of cheap scrap to play with 1st, but at the cost of materials you are talking, I'd balk just at what practice alone would cost me to get to the point I'd be comfortable taking on the job.

Having to agree with you hurts. It really does. I love TIG, but I always have to remind myself that I'm just one of those guys who "gets" it. There were only four of us in the TIG class who were even halfway on track, out of twenty or so.

[storeman]

I thought about that. And it's a lot a lot cheaper. I personally like the look and feel of solid.

Looks like you brought this onto yourself. Now to reorient yourself in light of "enlightenment". Then, to resell her on an alternative you might stand a chance of handling successfully.

[MetalMan23]

I remember welding a box out of 1/4" copper plate using a sychrowave 300 (or was it a 250?) And I was amazed at how much heat it took.

As far as learning TIG welding, I was stacking dimes on aluminum a couple days after picking up a TIG torch for the first time. I got better than my boss after a couple weeks. It came naturally to me I guess .

[storeman]

I remember welding a box out of 1/4" copper plate using a sychrowave 300 (or was it a 250?) And I was amazed at how much heat it took.

As far as learning TIG welding, I was stacking dimes on aluminum a couple days after picking up a TIG torch for the first time. I got better than my boss after a couple weeks. It came naturally to me I guess .

M/Man, I wish it would come to me that easily. I shake too much I guess.
Jerry

[okayenergy]

Have you tried to use oxyhydrogen for copper joints brazing? i go through a web and discussion about how to use oxyhydrogen for copper tube brazing?

[TheBFA]

Thanks! I was planning on practicing until it was something I was happy with and who knows how long that would take. And for the sanding, I was just going to lightly sand with 400 just to get some scratches to produce a brushed effect, stopping at 45's where all the joints are to make the joints appear to be three way miters.

If you don't already know a good trick for that use some masking tape to mask the angles when you sand. I've done lots of grinding down, polishing, and putting a brush finish on miter joints and it works great. But you want to pull away from the tape when you sand, and not into it.

[grumpycricket]

Contact pro for this job. I've tig'd & mig'd a lot of copper, professionally. For most people, this is well above the diy knowledge & skill set.