Copper Welding

[Nidgodh]

Hey guys,

like I mentioned today in another post, I tried again to do some copper welding using TIG /141/ method. Base material was Copper 99.5% thickness 2 mm, filler material was CuSn diameter 2 mm. Welding was done using 4T settings (no pedal) and argon only was used. Two joints were produced, first was fillet weld in welding position PB and second was ''I'' joint in welding position PA. Fillet joint was welded using 150A, ''I'' joint using 135A. Because I didn't use pedal I was forced to stop, let cool the piece and restart on filled joint in welding position PB 3 times (there are visible two small tie-ins on pictures). I also tried to polish that copper PA joint for first time, I achieved mirror finish (I could see myself on that plate nicely). Of course there are some little scratches (I'm far from perfect on copper, those scratches just didn't wanted to go away!), but you can get the picture. Anyway, ''I'' joint in welding position PA, was fully penetrated in full length (will add photo on Monday). The front site of ''I'' joint was polished only, backside is without polish finish. If anybody did copper welding, please share, it's quite hard and unpredictable, welding pool flows like water and it can make hole just like that...

 

[doubleboost]

Welding copper is used on some commercially produced miniature steam boilers.
I think I have some images .
Your welds look very good

 

[Brad93]

Never done it but keep meaning to give it a try.

 

[Maker]

Very impressive, especially on small test coupons. I've had a very quick go at tigging copper, it almost looked like it was working then suddenly everything melted into about an inch wide hole.

 

[imagedude]

Copper is an element not an alloy so it has a melting point rather than a melting range which is why one second it's a solid, the next it's a liquid...

 

[Barking Mat]

Very pretty.

 

[James1979]

Who did a copper cake stand with TIG recently? I think @Munkul? They may be able to shed some light??

That looks really good, I've never tried so I'm no help!!

 

[Turbo]

Where I worked the copper pipes on the steam boilers were joined with something similar to that. It was called copper tek welding using square bronze coloured rods & done with oxy acetylene or a mapp gas torch on smaller stuff, it left a copper coloured rippled finish as if it was tigged.

A few of us tried to do it but couldn't get a nice consistent bead so we always got a heating engineer in do do the welding, he made it look easy.

 

[chris pruteanu]

I weld many alambics to distill alcohol in either stainless steel or copper, I welded many... Your welds look good and consistent !

 

[Brad93]

Where I worked the copper pipes on the steam boilers were joined with something similar to that. It was called copper tek welding using square bronze coloured rods & done with oxy acetylene or a mapp gas torch on smaller stuff, it left a copper coloured rippled finish as if it was tigged.

A few of us tried to do it but couldn't get a nice consistent bead so we always got a heating engineer in do do the welding, he made it look easy.

That’s phosphorous copper rod. Used on lines where you don’t want any flux inside from brazing or soldering.

 

[Kram]

This is something I wanted to play with, I am still a complete beginner It did sag a bit, had amps too high.

It was good practise anyway

 

[AndersK]

They look awesome

Not done much copper but two things I learned hit it with lots of amps to heat saturate then back off to just a fraction. Use a long filler rod. Short ones absorb a lot of heat that quickly travel to fingers

 

[Barking Mat]

I did some autogenous , (no filler rod), copper bits, when I first got my tig, just for fun, nothing like the opening post.

 

[Munkul]

They look awesome

Not done much copper but two things I learned hit it with lots of amps to heat saturate then back off to just a fraction. Use a long filler rod. Short ones absorb a lot of heat that quickly travel to fingers

Top tips I found exactly the same making my cake stand. Long steady runs are easy to saturate and get the heat just right, it's as easy as steel, just a lot hotter. Short runs and awkward shapes are trickier to manage heat.

 

[Munkul]

Really nice work!

 

[Liquid Metal]

Have never tried welding copper, always fancied giving it a go but never got around to it.
May be miles out, but one thing im sure I remember from college though, was that for materials like aluminium and especially copper, which conduct heat as quickly as they do, using helium (or a helium mix) rather than straight argon, gives a better result due to a much higher temperature of the plasma within the arc.
It allows you to travel at a much higher rate, lessening the heat saturation and makes it less likely to blow a hole.

Maybe think of it like welding two pieces of stainless that are 2mm thick. Either weld it with 1.6mm filler at 120 amps and fast travel speed. Nice fluid puddle, flows nicely, penetrates easily.
Or weld it at 60 amps moving slowly. Have to keep waiting, puddle ambles it's way along, always on the verge of blowing a hole after an inch or two along the joint.
Then look at the oxidation colours around the weld and the width of the HAZ.