sorry for got to mention , already tried silver solder ,and had hard time heating the metal to the correct temp. actually the flux started burning before the solder melted, and the burned flux left a black residue which repelled the solder even more.
Most hardware stores carry pure tin solder in small rolls. It is required by code for copper pipes used for drinking water. The Zinc Chloride flux is a litle harder to find. It is used by a lot of sheet metal shops for soldering galvanized steel seams.