I have cleaned up and soldered Supergirl’s cape that was cast in a yellow brass a few days ago. I used my larger Smith acetylene-air torch that gives me 13,000 BTU to heat the two pieces, and fortunately this was sufficient to get the piece locally hot enough (760 C) for my bronze solder to flow. However, this did push the torch to it’s heat capacity or limit.
Once the joint was fully soldered I had to flip the piece over and re-heat to fill the other side. The solder is essentially acting as a filler for any spaces or cavities in the joint.
The final picture shows the cape cleaned and semi-polished. It’s now waiting for coloring with my red transparent cold enamel. I’ll do this at final assembly when Supergirl is complete. This cape weighs 367 grams.