I have small leak on a soldered 90 degree joint I cant get the copper joint to take solder can I fix that or doI have start all over, the solder just rolls off, can I braze over the solder with something else that will stick. seems like there should be a little trick that I dont know about.
You might be better off redoing the joint. If the solder did not flow into the joint properly, then anything you do on the surface will not improve the integrity of the joint and you could have additional leakage some time in the future. Possibly when the joint blows apart. I have seen joints last for 15 years and then separate when someone dropped a can of peas on it.