Broke radiator overflow line...........

[Tom Wesenberg]

It shouldn't be too hard to solder in a complete new tube.

If you want to repair this tube, and looks are important, then you could buy a short piece of thin brass tube from a hobby store and solder it to the inside of the pipe and solder the splice seam smooth. You'd have to clean the inside of both pieces very well so the solder sticks to them as well as the brass splice.