Silicon Bronze Brazing

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Hi all,I'm a novice welder trying to mig braze some copper sheet metal together for an art project. I'm using .023 silicon bronze wire on a Lincoln 140HD with Argon gas. The problem is that the braze doesn't stick to the copper and creates little globules that fall right off. I've tried varying power and speed and don't notice much difference in the outcome. Anybody have any ideas why this might be happening? Thank you!
Reply:What has are you using?Last edited by tapwelder; 9 Hours Ago at 06:15 PM.
Reply:I'm using Argon
Reply:100 percent?https://www.millerwelds.com/resource...brazing-basics
Reply:Yes, 100%
Reply:Is your copper clean? No coating?  Actually copper sheet? Thickness?
Reply:Yes, it's copper sheet and I've sanded the areas to be brazed. It's 24 gauge, fairly thin.
Reply:Polarity? What wire was in your machine previously?  Ground connection solid?
Reply:Polarity is DCEP. I had stainless steel in there previously. As far as the ground connection, I clamped right onto the sheet so I think it was pretty solid.
Reply:It seems like you are not getting enough heat for  capillary  suction.  I have a spool of  030  silicon  bronze  wire.I haven't tried it yet  But I'm  sure it is  recommended   130 to  140 amps  that is probably  more than your 140 can  handleLast edited by Josey; 7 Hours Ago at 08:39 PM.
Reply:I was afraid it could be something like that.
Reply:Try preheat.
Reply:

Originally Posted by tapwelder

Try preheat.