Following up on our recent soldering tip, Sweetwater Sales Engineer, Clay Stahlka provides more instruction for beginners.
Maintaining the proper temperature at the tip is imperative to making good clean connections, especially when working with printed circuit boards. Short of purchasing an expensive variable temperature soldering station, this can be accomplished by using a dimmer switch. You know, one of the rotary wall dimmer switches like the kind you might use to dim the lights in your house (Ed – Please, put it into an enclosure so you don’t electrocute yourself). This will allow you to obtain a temperature just hot enough to melt the solder but not so hot as to damage traces on a circuit board. Also, since overheating solder will cause the possibility of “cold” solder joints, this will prevent bad connections on any type of solder joint. Also, make a note that when soldering stranded wire you should lightly tin the wire up to 1/64″ below the insulation so that each strand is tinned with solder but is still visible individually. You should also tin the receptacle with solder so that the amount of heat needed to make the connection is minimized. Place the tinned wire in the receptacle and apply only enough heat to see the solder flow from the receptacle to the stranded wire and immediately remove the iron. This insures a good electrical connection and minimizes the chance of a “cold” solder joint. Application of too much solder has no electrical value, does not add any strength to the connection and looks sloppy and wastes money. Application of too much heat will cause “wicking” up the stranded cable, under the insulation, making the wire brittle and opening you up to the possibility that the wire may break if it is flexed repeatedly where the solder has flowed.