If you are looking to use lesser amps, you can tig weld using grade III silver. It melts at way less temperature than copper. It won't be a perfect color match but it will be strong. Make sure you don't melt the base material before you start to add the Grade III. Start the arc, keep dabbing with the Grade III until it begins to flow. You'll get the hang of it in no time. If you do it right, it can look similar to an aluminum tig joint.