Clean the parts well as others have mentioned and get the heat right - thats the secret. Stay-Brite is agood silver solder and is easy to use-I have used it on a lot of control systems with the gold Sullivan links. No failures with Stay Brite but have had one failure using electrical solder-the rudder joint failed after many flights on a Kaos but igot away with it! Bob Violet recommends Stay Brite for the linkages on his line of jet models-thats agood testament.
Al Watson