Common Soldering Problems
The ideal solder joint for through-hole components should have a wetting angle between 40 and 70 degrees from horizontal, and a smooth, shiny and concave surface. However, it’s really not easy to do. And we always face the following soldering problems.
Overheated joint: Sometimes we may have an overheated joint, and that is because the solder has not yet flowed well and the residue of burnt flux cause troubles in fixing this joint. Actually, we can prevent this issue by properly prepared, such as a clean and hot soldering iron, and clean joint timely.
Too much solder: This might be a perfectly good joint, but it is entirely possible that a blob of solder wets neither the pin nor the pad and is not a reliable electrical connection. If it happens, to draw off some of the excess solder with the tip of a hot iron is a good method. In extreme cases, a solder-sucker or some solder wick can be helpful as well.
Untrimmed leads: Leads that are too long easily cause short circuits. It would not take much force to bend that lead over to touch an adjacent trace. However, it is not difficult to tackle this issue, just to trim all leads at the top of the solder joint.