Hi, all,
I have some fittings I am making out of scrap 1/4 inch bronze. I am TIG welding them -- or trying to! The fittings are about 2"x14", and I just need to weld some little pieces onto them. I have found that the metal just seems to suck up heat and disperse it -- gotta crank at 200 amps (my top). Once the whole thing heats up cherry red it seems to weld OK, but by then my air-cooled torch is about ready to flop over and the heat coming off the fitting is pretty intense.
Are there any tricks to this beyond raw power and a water-cooled torch? I've never run into this problem with steel.
Thanks,
Chris
I suppose that makes sense -- perhaps that is pretty much what I'm doing with the TIG. Maybe this would be a good excuse to buy me a torch!
Far be it from me to disturb a man's excuse to buy a torch but charcoal in a hibachi should preheat them just fine.
Bill
OK, folks, I tried this again... I preheated with a propane torch and then went to work with the TIG. This stuff was VERY hard to get to temperature -- the piece was throwing off so much heat that it burned me through my TIG gloves (admittedly not heavy gloves, but still... it isn't like I was picking the piece up). Is this par for the course with copper alloys or did I happen to pick up some particularly heat resistant alloy? (This stuff came from a scrap yard -- looks very coppery, might actually be copper for all I know, though I don't know why people would have made brackets out of solid copper.) I was barely able to do two inch long bead, and then got greedy and did another two inch bead (easier now that the whole thing was glowing red) before the thing got too hot for me. And my torch threatened to melt.
Any help you guys can give would be very much appreciated -- scrap yard charged me $1.50/pound for this stuff, and I'm on the verge of throwing it away. I've always liked welding bronze in the past, but maybe the size of these parts is just too hefty for my setup (?).
Thanks,
Chris
By the way, you mention copper........if it is in fact copper you will have a b*tch of a time Tigging it. Copper requires an enormous amount of preheat compared to bronze. Wish I would have finished reading your other posts before answering but it sounds to me as though you have something with a very high copper content if its not copper.
Chris;
What are you doing with your TIG? I have welded loads and loads of bronze and found it welds absolutely beautifully with AC. That was ages ago but I never had any problems at all. Are you using any filler and, if so, what are you using?
Thanks for all your helpful replies. I suspect that I might, in fact, have a pure copper or high-copper alloy. This stuff is nothing like the silicon bronze I have welded in the past. However, I had a little better luck welding it yesterday: I preheated it as much as I could with a propane torch, then went at it with maximum heat from the TIG. Once the whole piece got super-unbelievably hot, I was able to ramp down the heat and focus on the welding bead area. Seems to work pretty well, although I have to stop frequently and let my torch cool down. And my gloves. It is like the whole piece has to be right on the edge of melting.
I have been using silicon bronze rod -- anyone know if these welds are doomed? One of them passed the hammer test last night. I have been using DC TIG -- should I use AC on bronze? I really don't think I could get enough heat into it with AC. Also, some guide I saw said one should use helium with copper rather than argon -- why would this be?
Oh yeah, one odd thing I've noticed about welding this stuff is that it tends to get this black crust on it as it is cooling which then pops off as it cools further. (You can hear it happening.) It is kindof entertaining. The remainder of the black stuff comes off pretty easily with a wire brush.
Thanks,
Chris
Chris;
I'm copying (below) an e-mail sent to me about copper welding by Niekie Jooste, a person I have great respect and admiration for. See what you think:
I have dealt with TIG welding of copper. It is definitely possible, but the high thermal conductivity of copper is a big problem. You generally need to provide high pre-heats and high currents to get the parent metal to actually melt sufficiently to perform the welding operation. (This is also very dependant on the material thickness.) For this reason, GMAW is the process of choice when conventionally welding copper. In the right circumstances thermite welding can be performed. Where the circumstances are right, this is probably the most successful process.
Regarding the weldability of the copper and the best filler to use, I can not really give you advice without knowing the actual details of the metals to be joined. When you talk about carbon or carbon-nickel material, I assume you mean carbon steel? If this is the case, then you will need to have a much more carefull look at the whole joining procedure, whatever process you use.
Another issue to keep in mind when performing repair welding, is the reason for failure in the first place. If it was due to stress corrosion cracking (which can happen to some Cu alloys) then any repair will be extremely difficult if not impossible.
Regards
Niekie Jooste
Principal Member – Fabristruct Solutions
Hello Chris,
If you're observing a black crust that seems to flake off on cooling, I'd suspect that you definitely have a high copper alloy, or perhaps just plain old copper. I've observed this as well when welding 'pure' copper, but not so much when welding brass/bronze.
If your base material is close to pure copper, I'd think twice about welding it in the first place if your parts are intended for anything structural in the end...copper usually becomes dead soft after heating it near it's melting point due to re-crystallization processes. However, if it is in fact an alloy, this might not be true.
If it were me, I'd give soldering a try. If the joints are designed well, and particular attention is given to cleanliness, proper fluxing, and uniform heating, you should get nice joints with strength to spare. Just my .02 worth. Hope this helps, and keep us posted on how it turns out.
Chris
Thanks for all the help! I'm going to give my welding a serious hammer test tonight. These brackets are to hold up a bench in a shower I'm tiling. Copper would look pretty but if the bench dumps my wife on the floor I'm not likely to hear the end of it for some time!
Chris
By p61b
Date 10-24-2003 00:00
Helium will increase your heat input quite a bit. I've run 75/25% helium (He)/Argon (Ar) on aluminum bronze. With DC+ and 100% argon I had the same problems you have. Using 75/25% He/Ar I could turn the amperage down and weld without difficulty. Of course that was aluminum bronze. I don't know what alloy you are trying to weld. I mixed AMPCO brazing flux with alchohol to a milky consistancey, painted the bare wire filler rod and let it dry. With flux my puddle would wet nicely. Too heavey a coating of flux and it would pop in the heat of the arc.
If that's not enough heat input try 100% He, but not in a breeze. Helium is extremely light.
OK, y'all, I think that these suckers are PURE COPPER. I was able to bend one last night by standing on it. And I got a sample of copper and wirebrushed both and compared colors. Very close in color.
Thanks for all your help. I have to say that this stuff is very beautiful -- especially when you heat it and it turns all these colors. I'll have to figure out some non-structural use for it.
Chris
