Welding silicon bronze -- am I doing something wrong?

Question

I'm just beginning to play around with silicon bronze. I tried TIG welding some sheet (.065") and noticed that the bronze does not behave like any other metals I have welded (steel, stainless, copper). The molten bronze seems to be much more viscous with a much higher surface tension; it doesn't flow nearly as readily as the other metals and it has a tendency to pull itself into blobs. Is this just the nature of the beast, or should I be doing something different, like using a flux, or a different shielding gas (argon), or a higher gas flow rate (15 cfh)? Any tips or tricks? Or do I just need to practice more and learn how to compensate for these characteristics? Thanks for any suggestions.

Bert

Phil · Accepted Answer

Hello Bert    I have TIG welded a fair amount of sil. bronze and most of the time it has worked out OK , almost sounds like you are either running it too cold or the steel isn't clean , I usually use the bronze on something that I would prefer not to get very hot or on thin stock to avoid warping , the SS and plain steel filler rod is designed to be mixed or melted into the base metal , bronze works more like silver solder and other no ferrous metal , it goes on by surface alloy as opposed to mixing with base metal , would make sure metal is clean and it may help to sand or scotch bright the weld wire.Good LuckPhil

Phil · Answer

10 CFH should be plenty of gas , use 100% Argon and absolutly don't use any Flux .Phil

Ipeak · Answer

As Phil says, you DO NOT MELT THE BASE METAL!  On a fillet joint,holding the rod in one hand, lay the rod in the joint and run the TIGarc along over it, melting and flowing the filler, wetting the basemetal.

Bert · Answer

Hey Phil,Sounds like you're talking about brazing with bronze -- i.e., using itto join a different base metal (steel). I'm talking about welding withit -- i.e., the base metal and filler metal are both Si bronze. Bert"Phil"  wrote:

patrick · Answer

I am working on a project with architectural bronze alloy 385. There is a national organization of copper-www.copper.org or .com, but I couldn't find relevant info on welding or brazing bronzes.

I've heard that brazing is the process to use for joining brasses or bronzes, though I think they can be welded too. Anyone know for certain?

Patrick

Eric R Snow · Answer

Greetings Patrick,Generally, when people say brass they mean a copper alloy with zinc init, and when they say bronze they mean a copper alloy without zinc init. However, this is technically wrong and many copper alloys calledbronze contain zinc. Some bronze alloys can be welded with bronzefiller rod. Silicon bronze is one that welds particularly well withsilicon bronze rod. TIG welding that is. I personally have noexperience using other methods of welding silicon bronze. TIG weldingbronzes that contain zinc is tough because the zinc boils at a lowtemperature and actually vaporises from the high temperature of theelectric arc. Bronze alloy 385 is another name for copper alloyC38500. Look at this link: 't try to TIG weld it. It is 40% zinc. However it can welded, or,if you prefer, brazed, with a torch. Brazing rod comes in manydifferent alloys. Pick one that has a lower melting temperature.Cheers,Eric

Rod Day · Answer

Hi Patrick,I have exclusively welded silicon bronze with the TIG as well and it is one of the easiest form of TIG welding I have found. The filler metals I have used were identical to the parent metal, no fluxes, get puddle of molten metal and off you go. Most of the work has been on sculptures with a large thickness.Good luck

Shadowland · Answer

Curious why someone welds brass rather than braze ? Since brass isn't used in high stress applications anyhow.

cmignacco · Answer

and i recommend ac

Ernie Leimkuhler · Answer

I prefer DCEN with a helium argon mix gas. Helium makes copper allows very happy.

Welding silicon bronze -- am I doing something wrong?

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