Trying to apply some solder to the pinhole leak in the tubing on my Bosch water heater heat exchanger and it beads and rolls right off. Yes, I cleaned it, buffed with emery cloth and fluxed. It looks like copper, cleaned up and sanded like copper, but no go on the solder. No problem at all getting the solder to adhere beautifully to the jacket and of course to any of my copper fittings other jobs.
What could be going on with this material that looks like it’s copper?
What could be going on with this material that looks like it’s copper?