If I may I’d like to add this guys, Brian is correct in that pure copper is excellent for a back up with your mig or tig and small scrap pieces are readily available almost anywhere. How ever, when it comes to the copper alloys such as brass, which is alloyed with Zinc, and Bronze which is alloyed with tin, both of these alloys have a low melting point. I would not recommend using any of the copper alloys for a back up. Your almost guaranteeing that you are going to contaminate the weld puddle by using these as a back up heat sink.
Denny Graham
Sandwich, IL
