As many of you have looked at an over flow bottle for your car I'm sure you thought "Hey, I just solder something out of plumbing pipe." And you did, you looked at it and said, Nope not so swell. For a while now I have pondered the thought, " Can I TIG weld copper?" Since plumbing is my life this is a question I should surely know the answer to. First, don't call me Shirley. Second, let's follow as I more or less stumble through this process. I was not entirely sure of what type of emissions I may create doing this, so I put on a remote air supply mask that I use for lead work. I you have thoughts on this pipe in. I did taste like a penny for a bit. So let's all learn together. Try to give me a bit of time to post up. I'm a tinge slowish with the whole info thread process. Thanks.
I took a length of 2" type L copper tube and measured out an 18" section of it, cleaned it, located (2) 2" caps and cleaned them as well. I drilled a pressure relief hole in one of the caps, 1/8" hole is fine.
I then took a length of regular house wire 14 gauge stripped it to make a rod and cleaned it with some scotch brite. I proceeded to TIG in the copper wire using a green electrode, a big one, electrode positive and a very hot setting. I seemed as if the copper really needs to get hot or up to temp. I sat there with this TIG head cooking on an area for a minute or longer, the work really got hot, it carburized heavily, however it soon started running a fair bead. It was always just a tickle away from a bow out though. So I tIG'd up both sides of it.
I fashioned a couple of mounting tabs, and fit the drain, a fitting for a cap and the flow tube onto it. Each time heating the bloody heck out of it.
In the end I have this as an overflow container. It still looks rather simple, yet it does command a bit more respect than one that was simply soldered, it does not have the silver solder bands on it and being TIG welded copper will present the eye that sees it with an effect they may not see every day. In the end I think the process will draw a bit of dignity. The working temperature of this piece was very high, almost had to cherry red the whole piece. I set my Miller 200 at 150 amps, a small lightning storm. Granted, I may have been doing something wrong, but I did get a result and a favorable one to me. I used a 90% argon shielding gas at 10 pounds delivered. I think I am going to play some more with preheating the work with a large propane torch to get my temp, I feel I may not need to "throw" so much current at the work and may get a better weld look. Next for this part is a finish polish of some of the areas that I had to mess with, I then want to acid dunk it in a 25% solution of Muriatic, air season it and wipe it with a rag with 10% Muriatic acid on it and rinse. I want to air dry the part so it color sets the oxide pattern deep into the copper and then high polish it. I have toyed with this treatment a bit, I may be able to get a polished patina finish with te acid colors of mild red green and orange into the final polish. And then lock them into the metal with a clear coat. Best part is that I get rid of my SS billety looking overflow, one more part towards the conversion of a street rod to a hot rod.
I TIG a fair amount of heavy aluminum, copper, and bronze. Also apply bronze as wear surfaces on steel parts. A little bit of helium goes a long ways towards helping get that high heat you need.
Please share your knowledge if you will. I just used my regular gas mix, if there is a specific mix that gives a better product that would help a lot. Also, how toxic are the emissions, I don't want anyone getting sick. Thanks.
When welding copper pipe I've found that a pure tungston electrode, straight argon shield gas, and the smallest filler wire you can get away with is what works for me. All my experience with this has been with schedule 40 or schedule 80 pipe however. Yours looks good. My welding now has to be done with a cheater lens and fairly light shade. Very little welding gives me very much head ache now. Damn whats gonna happen when I do get old?
I set my auto darkener at 10 for this, that's why I have the Dr P, I found a dose of caffeine helps me at the welder, I can see better. I work faster too.
Great job! Copper is a tough one to weld for the same reason Aluminum is difficult, the heat conductive properties of the metal whisk heat away from the area you're trying to weld and dispersing it throughout the piece. Great for a radiator, tough to weld!
First of all, anything that involves heating of copper and bronze gives off stuff you shouldn't be breathing on a regular basis. A bit of gentle ventilation is mandatory. Re: the helium. This was taught to me by a friend that welds molds. Huge molds, made from aluminum. Pre-heating for him isn't usually an option. Helium turns out to be a great option. It really ups the heat level. We have Miller 250dx tigrunner. With argon and AC it trips out pretty quickly trying to run 3/8" beads. Mix in about 15% helium with the argon and we can weld for hours. The consumption rate running pure helium is around ten times that of argon. So it gets expensive fast. But even adding only 15% really ups the heat and drops the current required significantly. I also do a lot of aluminum welding using DC, but with DC, helium is a must. As mentioned by another poster, the problem with aluminum, copper, bronze etc, is their ability to conduct heat quickly. Preheating helps, but try adding a bit of helium next time. You will be pleasantly surprised. We run a splitter valve at the gas intake port on our box. Both argon and helium are connected to it. Each bottle has a flow control that we can use to attenuate the percentages. You can buy helium mixed gases. We prefer to keep a bottle of argon and a bottle of helium. Mix to suit.
The key to a good copper weld is using de-oxygenated welding rods. I put together a couple of large stills for the son-in-law's micro-distillery using 3x5 copper sheet (which, by the way cost almost 400 bux each). Anyway, building a 70 gallon water tight vessel is a good way to get lots of practice welding copper. The HAZ marks were about 3 inches wide - an indication of how well copper conducts heat. I found it welds nice (with the above rods) somewhere between alloy and steel. Great project!
Just a thought regarding preheat. Have you considered using one of the clamp on electric heaters that are being used by plumbing & heating contractors? Nice work by the way. Mike
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