china pcb manufacturer and Desoldering Basics - Why and How

Desoldering Basics - Why and How Soldering is the process of joining two or more parts together with a fusible alloy, such as tin or lead, using a heated instrument called a soldering iron.

Soldered joints, if improperly done, may need to have the solder removed in order to re-solder them. A poor joint may result in complete failure of the electrical connection over a period of time. Poor quality of solder, improper cleaning of the surface before soldering, lack of correct technique, corrosion of the joint due to leftover flux, movement (shake) of the joint before the solder has cooled may all cause a poor soldered joint.

Re-soldering may also be required in order to replace a defective electronic component or to troubleshoot an electronics problem.

The process of removing solder and components is called desoldering.

There are a few common methods of desoldering. The two most commons techniques are described below. What they have in common is that both require the use of a soldering iron to complete the task.

A common method of desoldering is to use a desoldering pump that is a vacuum pump similar in operation to a bicycle pump, but in reverse. It has a spring-loaded plunger that breaks the solder and is sucked away by the pump. Repeated operation of the pump may be required in order to completely desolder a joint. The pump has to be operated carefully in order not to damage the PCB or the electronic component.

A solder wick or braid is an alternative to desoldering pumps. Here the copper wick is placed over the joint and the solder is melted by means of a soldering iron. The solder gradually flows into the wick and hence gets removed. The wick must be removed from the PCB before it cools down as otherwise it may damage the board.

Something you might want to take into consideration is that solder wick is the more expensive alternative so if you need to do a lot of desoldering, you may want to use the solder pump as your primary method, then use the solder wick to complete the task.

It is recommended that a soldering iron in the 15W to 30W range be used. Soldering irons with higher wattage may result in damage to the board or components, however some heavier connections (like a chassis) may require a higher wattage iron to properly remove all the solder.

Take precautions when working with solder. Do your work in a well-ventilated area as fumes from the resin can get into your lungs or eyes. Be careful not to let the hot solder splash you. You could get severely burned. Lastly, consider using eye protection such as work goggles when working with solder.

Desoldering is not as difficult as you might think. Take heed of the precautions and follow the suggested methods for an easy desoldering experience.

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