Best process for joining copper ?

[tom in nh]

Looking for a capable process / machine to join thin copper sheet / tubing together.

Soldering, fusion welding, brazing, or ?

Copper is 16oz / .023" thick. Also have .010" thick copper sheet. Varying tube wall thicknesses too.

Neatness of joints in the end product is important (an elaborate copper weathervane), as is the need to hold together for the next 100 years.

I am used to working with steel - copper is new territory for me.

220 single phase power is available.

What would you use for equipment?
Required book reading, etc. ?

Any other suggestions would be appreciated.

Thank you.

 

[seber]

Spot welding would be my choice.

 

[Firebrick43]

Are you making one, a hundred, a thousand?

Silver brazing will give you very neat joints if you fit them up correctly one offs can be done by hand with a small torch. The flux if washed of with hot water isn’t corrosive.

If doing more quality small premade rings and ribbon can be purchased that are put in place and heated either by torch or furnace. This is how ac coils many times are made.

Solder can be used as well but joints need to have more over lap as the solder doesn’t have the tensile strength. There are a lot of copper roofs and eaves out there soldered with lifespans between 60-100 years.

Spot welder certainly work as well but you would need to be careful as especially horizontal lap joints will hold water and the corrosion will tend to jack the seam apart.

 

[lilredex]

Silver soldering would be my choice. Plumber's (acetylene) or O/A will do to give solid and neat joints. Practice is in order if it's new to you.

 

[Beerhippie]

If you want a deep dive, there are plenty of YouTube videos on TIG welding copper.

I'd go with silver brazing.

 

[tom in nh]

Quantity is for two weathervanes.
Agreed about the need for weather tight connections. Maybe spot welding is not practical in this instance.
Silver soldering vs silver brazing? Please elaborate.
Keep the ideas flowing.
Thanks.

 

[Firebrick43]

Quantity is for two weathervanes.
Agreed about the need for weather tight connections. Maybe spot welding is not practical in this instance.
Silver soldering vs silver brazing? Please elaborate.
Keep the ideas flowing.
Thanks.

So its technically silver brazing because of the temperature (over 800 degrees). But historically for what ever reason it was called silver solder. To confuse things there is silver bearing solder which due to the temp is a true solder

 

[Firebrick43]

Silver Brazing

Video shows silver brazing techniques demonstrated on a bicycle lug frame

www.weldingtipsandtricks.com

 

[RoninB4]

-Another vote for silver brazing/soldering but that depends upon the function of the component. If it's circular/tubular does the ID or OD need to be a bearing surface, continuous, or single layer? I've done a fair bit of silver brazing and liked using it for various applications where I needed greater strength than common solder, cleaner joinery than brazing, and "wicked" into small openings quite well. For different "brazed" carbide tooling (many different types) what held the carbide attached to the steel body was silver solder, it held the carbide better than brass (according to the department as Spiral Step Tool).

 

[The Bean]

Yep. Silver solder.

 

[dscheidt]

So its technically silver brazing because of the temperature (over 800 degrees). But historically for what ever reason it was called silver solder. To confuse things there is silver bearing solder which due to the temp is a true solder

In the argot I learned, silver solder has tightly fitted joints, and the filler is pulled in by capillary action, like lap joints. silver brazing is used for joints where the filler is built up on the surface, like for **** or fillet joints, or filling cracks. same materials get used for both, but different joint types.

 

[1320stang]

I don't see folding or folded seam as an option for the sheet goods....

 

[Firebrick43]

In the argot I learned, silver solder has tightly fitted joints, and the filler is pulled in by capillary action, like lap joints. silver brazing is used for joints where the filler is built up on the surface, like for **** or fillet joints, or filling cracks. same materials get used for both, but different joint types.

Argot?

Possibly that is where it from? It certainly has enough historical backing of people calling it silver soldering that I wouldn’t question someone using it other than to insure that they were not actually talking about low temp silver bearing solder.

I have never really been able to do large silver brazing fillets/beads like I can with careful heat control of bronze brazing.

 

[ronkz650]

Any solder works good on copper. It's probably the easiest metal to solder to.

 

[ArcIndWeld]

I'm a big fan of tig welding copper myself but it is a challenge to get the hang of. I would most likely silver solder them.

 

[Beerhippie]

Any solder works good on copper. It's probably the easiest metal to solder to.

Not knowing what kind of joints the OP wants to make, hard to say what would be best....

 

[Death Row Dave]

I like the newer crimp copper fitting

 

[Beerhippie]

I like the newer crimp copper fitting

????

 

[tom in nh]

I will attach a photo later on this evening.
What kind of tig machine will work with thin copper sheet and tubing?

 

[PCustoms]

I like the newer crimp copper fitting

????

He read the thread title only...

Any reason to not just use straight lead solder, like old-school gutters? I'm pretty sure I've seen a weathervane or two made that way

 

[NHtoolguy]

He read the thread title only...

Any reason to not just use straight lead solder, like old-school gutters? I'm pretty sure I've seen a weathervane or two made that way

I agree that lead solder is an option to consider. It has good weather resistance and is easy to apply to clean, tight joints. But, as has been mentioned, it has low tensile strength so it's not appropriate for highly-stressed joints. For those areas, I would use silver solder.

 

[dr_clyde]

Joint design plays a HUGE role here.

Soldering/brazing works best with some sort of seam or joint to allow capillary action to wick solder into the joint, providing strength. It doesn't work as well as a substitute for a fillet weld. If the joints allow it, silver braze is how I would want to do it. I wouldn't want to try to solder/braze a tube to a sheet without some sort of flange or seam. Just a fillet would warp pretty bad and not have much strength.

Spot welding is out, that would take an extraordinary amount of amperage to spot weld copper. The electrodes of the machine are made from copper, remember? Laser welding would be the "best" way, but not even close to affordable for making 2 weather vanes.

TIG is an option, but it takes some practice and skill to weld copper. I've done it, works best on thinner sections. Thicker stuff takes mega amps or a lot of pre-heat. You can buy de-oxidized copper filler wire, but most of the guys I know just strip back some romex. For a weathervane, this would work fine. Welded joints are also very strong, but keep in mind the annealing effect the welding heat has on the base metal.

 

[dscheidt]

Argot?

Possibly that is where it from? It certainly has enough historical backing of people calling it silver soldering that I wouldn’t question someone using it other than to insure that they were not actually talking about low temp silver bearing solder.

I have never really been able to do large silver brazing fillets/beads like I can with careful heat control of bronze brazing.

An argot is the specialized language of a group. The original meaning was the cant thieves used to be able to talk about criminal activity in a way that someone overhearing couldn't understand, but modern usage is broader.

 

[bwringer]

Silver solder can be ridiculously strong; it's what is used to make steam pressure vessels for model steam engines.

However, it can also be... messy. And it takes huge amounts of heat.

Here's a good overview from the Blondihacks YouTube channel:

Note that even after careful cleaning and proof testing to double working pressure, the appearance of this copper boiler is really messy.


For the OP's question, where aesthetics matter and it's not carrying drinking water, I'd guess that leaded solder (careful about the fumes) will be easier to work with, doesn't require nearly as much heat, and overall will be less "messy". The copper will weather to a nice green verdigris, and the leaded solder will become an unobtrusive dull gray. Something like stained glass.


Then again, we know absolutely nothing about the design, so the question is along the lines of "how long is a piece of string?". Heck, maybe riveted joints would be practical, easy, and could look really cool. At many points, Blondihacks holds parts together with tiny brass screws that end up being soldered then filed flat and pretty much disappear. Or maybe there are places where a crimp or seam to hold sheets together would make sense.

 

[danski0224]

Hard copper rivets, sometimes called "tinners rivets". They come in different diameters (pretty sure that the original spec is by weight of a quantity of them).

Properly installed, they aren't coming apart. There's pneumatic aircraft rivet setters that can be used to "cheat" vs using a Pexto setting tool and a hammer.

Almost all of the old hand made copper stuff was done with 50/50 lead solder. It doesn't stick (well) where the copper isn't fluxed. You can tin the 2 pieces and then put them together and heat it to join them.

Excess solder can be mechanically removed. There is skill in planning the joints so it looks good when it's done.

Open flame torches are not used. A soldering iron with a copper head (varying shapes and weights) is heated in an oven or by a flame. This heated chunk of copper heats the parts being joined.

The copper irons are shaped as necessary for the job. The faces that will attract the solder are treated (tinned) with sal-ammoniac. The solder won't stick to the untreated faces.

You'll be heating a huge area with an air-acetylene torch, discoloring and warping the copper.

Pretty sure that air-acetylene torches didn't exist 150 years ago (I didn't Google it), and certainly TIG welders didn't.

 

[housewolf]

I would probably use 50/50. I’m a (retired) plumber so I’m no stranger to soldering tube. I’ve done a few ornamental gadgets with copper too. The stuff I’ve done, I want to it tarnish/oxidize so I don’t really care about discoloring the copper so I used 15% silver solder. If you use 50/50 you should be able to immediately wipe off access with a paintbrush then go back with a dremel to get it bright again, making a really neat joint.

All I’ve ever made was out of scrap tubing, I’d like to see the OPs weathervane.

I’ve made several of these crosses, they’re really easy.


And this hummingbird feeder holder-

 

[LopezBart]

Copper can also be brazed with a low silver alloy called Sil-Fos. This is what refrigeration folks use for connections; it's much stronger than lead-tin solders and capable of withstanding much higher temps (not an issue in your case, of course).
This is much cheaper than higher percentage silver solders, and doesn't require as tight a joint. No flux is required when brazing copper:

SIL-FOS 15

www.lucasmilhaupt.com

 

[Beerhippie]

Copper can also be brazed with a low silver alloy called Sil-Fos. This is what refrigeration folks use for connections; it's much stronger than lead-tin solders and capable of withstanding much higher temps (not an issue in your case, of course).
This is much cheaper than higher percentage silver solders, and doesn't require as tight a joint. No flux is required when brazing copper:

SIL-FOS 15

www.lucasmilhaupt.com

Sil-Fos is also compatible with TIG brazing. Using the TIG for brazing should allow for a smaller heat-affected zone--maybe. Copper is so conductive of heat it's hard to say.

I've used Sil-Fos to TIG braze cracked cast iron pump volutes. It does a great job of it--with the usual pre-heat/anneal.

 

[Jim greengo]

Stay brite8 and a turbo torch.

 

[tom in nh]

OK, this is what I am looking to build.
Might take me awhile though....

 

[PCustoms]

Solder

 

[Beerhippie]

OK, this is what I am looking to build.
Might take me awhile though....

Really?

 

[The Bean]

3D printer would make quick work.

 

[LopezBart]

3D print in plastic, do "lost foam" casting in plaster using Zamak or similar zinc-aluminum alloy. Tricky with so many small sections.

If you want to build it up from discrete pieces, consider reading Kozo Hirakwa's books or watch Blondihacks on You Tube; she's using his techniques to build Kozo's A3 switcher.

 

[rancherbill]

I would suggest some of the exotic stuff I see like laser welding.

Learn a new process and get some great equipment.

(It's the GJ Way)

 

[Death Row Dave]

Furnace Brazing

 

[gte718p]

I would suggest some of the exotic stuff is see like laser welding.

Learn a new process and get some great equipment.

(It's the GJ Way)

In true GJ style, I'll see your laser and raise you an ultrasonic welder. Functionally it is just spot welding with a different process. However, it is awesome on copper.

 

[neophyte]

Do you want to anneal the copper while joining it ?
Brazing, high temp “silver soldering”, and welding all has the potential to anneal the copper, which will then require more “work hardening”, unless a lot of forming is done after the joining operation, or unless you use a heat treatable copper alloy, and have the equipment to heat treat the item afterward.
Basic 50/50 lead tin solder used to be used for basic plumbing, and can likely last 100 years when subjected to minimal strain.
This is likely the low hear solder used for copper roofs, or was the standard alloy.
Reinforcement with small copper rivets would prevent major issues if the solder somehow fails.
There are alternative lead free solders used fir plumbing nowadays that would be an alternative.
This plus a large electric soldering (200watt-500watt), iron should be able to join relatively this copper sheet quickly.
The large soldering irons can be found on eBay at way better than new prices usually.
Hexacon and American Beauty, are teo of the brands that make giant soldering irons, and are still in business if you want to make it easier to get soldering iron tips.
Remember to clean and flux properly, and to make sure to thoroughly clean off the flux after the soldering is done.
There are still sections of soldered copper pipe from the Roman empire around.

 

[ArcIndWeld]

I will attach a photo later on this evening.
What kind of tig machine will work with thin copper sheet and tubing?

You weld copper on DC so any dc tig would work but I personally would want HF start atleast. That being said its certainly not easy and requires very good gas coverage and heat sinks. Helium helps alot as a mix into the shielding gas that being said having seen the project it's doable but frustration is going to be through the roof. I vote for lost wax casting or soldering

 

[LopezBart]

Thinking about it, this is likely best made using a variety of techniques. The figures could be cast, but are likely to be quite heavy in copper alloys; extra credit is available for hollow casting . The boiler, wheels, etc. could readily be fabricated from sheet, rod, etc; initial assemblies would done w/ higher temperature solders; these can be joined w/ lower temp solders w/o the risk of trouble w/ previous joints.

There is enough stuff here to spend years learning....