Ditto with Rodney. Rosin core electrical solder is what I use. Plenty strong. What is nice about the electrical solder is that it is available in small diameters, which makes it much easier to control and apply IMO. I believe the stuff I have is under or around 1mm, got it at radio shack. Much nicer than working with the plumber solder. The large acid core stuff is so big it tends to push parts out of alignment during application. Cheers