There is no exact answer, as it depends on many factors. For example, it’s hard to determine a universal temperature for all desoldering tasks because the needed temperature depends on the solder alloy, flux type, age, depth of immersion of your soldering iron, and amount of solder joints desolder, etc.
What is desoldering?
Desoldering is the act of removing solder from a connection or component. A soldering iron (or soldering gun) is used to apply heat to the joint, melting the solder and removing it from the target object. In addition, you can use a solder wick to soak up solder from a circuit board enabling components to be removed or exchanged.
Desoldering tools serve to remove solder from a work area without damaging components, PCBs and other delicate items. However, a wrong temperature may not provide enough heat for this purpose or damage certain electronic parts with very thin plastic casings or metal pins that fly off when heated.
Why is it important to choose the right temperature for desoldering?
As one would expect, overheating during the desoldering process can lead to permanent damage. In addition, hot components may melt and damage the solder joint and the PCB, making the device unusable.
Choosing the right heat source is not always easy. For example, if you were to use too low a temperature, the solder would take forever and won’t melt properly. But if you were to use too high of a temperature, the solder would heat up very quickly and get damaged.
How to choose the right temperature for desoldering?
You should choose the soldering iron’s temperature according to the solder you are using. The iron temperature mustn’t exceed by too much the maximum temperature. Long-term exposure can damage components, especially if they are already hot! Some manufacturers advise against desoldering with too high a temperature to preserve components.
Standard solders have a melting point between 361,4 and 368,6 °F, yet you can also come across lead-free solders which melt at a higher temperature of about 422,6 °F. When the solder has melted, it flows freely and leaves no residue on the solder pads when cooled down.
Therefore, it is necessary to adjust the soldering iron temperature (usually between 392 °F and 536 °F) to avoid damaging components or heat-sensitive parts such as electrolytic capacitors.
How can I know if my soldering iron is hot enough?
The simplest way to estimate the temperature of your soldering iron is by observing the smoke coming off the solder joint. When your soldering tip is too cold to solder, you will see a slight bluish smoke coming off the solder joint. However, when your soldering tip is hot enough, it will produce white smoke. It is the result of the melting of the solder, which has a low melting point compared to your soldering tip. You can observe when your solder tip is hot enough to desolder by observing this phenomenon.