Desoldering is a process used to separate items that have been soldered together.
Desoldering describes the process of removing solder to separate electrical components. Someone may need to desolder to replace a component or some wiring, or just to remove excess solder from a joint. Desoldering requires a desoldering pump, sometimes called a “soldering iron”, or a solder wick or braid.
To desolder a joint, a person must use a soldering iron as well as one of the desoldering tools. The soldering iron melts the solder so it can be easily removed from the circuit. A 15 to 30 watt soldering iron is usually best for electronics and circuit boards. However, soldering irons should not be used as they can damage circuit boards and electrical components.
Preparation for desoldering is the same regardless of the tool used. The soldering iron must be heated to approximately 770°F (about 400°C) to desolder the electrical components. Its tip should be tinned, that is, coated with new solder and then cleaned with a damp sponge.
The hot soldering iron is held on the joint long enough to melt the solder if a desoldering pump is used. The pump is primed or primed by pushing the plunger down. It is then held against the joint with molten solder, and when the trigger is pulled, the solder is sucked up by the pump. If the pump does not remove all of the solder the first time, it is sometimes necessary to add new molten solder to the joint to loosen the old solder so that it comes out with the new one.
In one method of using a solder wick or braid, the soldering iron can be used to heat the joint like a solder cup, then the wick is placed into the molten solder. Capillary action sucks the solder into the roving material. Alternatively, the solder wick can be placed against the joint without heating, then the soldering iron is pressed against the wick, and the solder is sucked into the wick material as it melts. This method generally works best for small joints. For either method, the used wick is cut after filling it with solder.
A good desoldering job should remove all of the old solder so that the component can be replaced or the joint re-soldered. After removing the solder, a component can easily fall out or may need the help of pliers. Re-soldering must be done carefully to avoid having to de-solder again.