I was so sick of the rosin silver solder I almost wanted to throw it away. Doesn't matter. I had so many problems getting the solder to sharpen the copper plating on the circuit boards. I can't remember ever being in so much trouble. Even with this solder, it sometimes takes a long time to sharpen the connection. I think copper siding should not be copper but an alloy. By using the smaller .031 diameter and smaller tip I was able to get good connections most of the time. I end up using 392โฆ