How To Desolder a Circuit Board

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Dec 29, 2020|PCB Maintenance, Repair and Troubleshooting

Printed circuit boards (PCBs) contain various electronic pieces bonded together through a process called soldering. Solder is the process that joins metals and components together to produce an electrical current. But how do you remove solder from a circuit board? 

Desoldering involves separating components of a PCB from the solder so you can recycle, dispose of, repair, or replace the pieces. To take apart a circuit board, you need to know to desolder it. 

When is Desoldering Needed? 

Desoldering is a crucial process required for a variety of reasons: 

• To replace a defective piece of the motherboard. 
• To modify an existing circuit. 
• To salvage components for reuse in another PCB or recycling. 

Since desoldering is a critical process to know, how do you desolder a motherboard? While there are several ways to remove solder, there are two methods commonly used to desolder. 

Desolder Wick/Braid Method

The desoldering wick method is an easy way to remove excess solder and easily replace or recycle parts of a circuit board. It involves the use of a soldering iron and thin, braided copper wires. The wires are coated with flux, a chemical purifying agent. You can make wick or purchase braids on rolls in varying widths. 

How Do You Use a Desolder Wick? 

As you place a solder wick over the bonded joint, heat it with a soldering iron. The braid’s flux will activate, while the solder melts, which attracts the solder up into the braided wires. You can desolder a circuit board with a wick in a few simple steps. 

1. Unroll some wick and add some flux (if it’s not already on there or if you want more). 
2. Put the end of the wick on the solder joint. 
3. Press the hot iron on top of the wick. Hold it in place while the wick and solder heat up.
4. Lift the wick and the iron while the solder is still melted. 
5. Cut off the used wick as soon as you’re done. 
6. Repeat until you’ve desoldered all the joints of the electronic component. 
7. Using pliers, remove the part from the motherboard. 

Pros and Cons of the Desolder Wick Method

The desolder wick method is one of the easiest ways to desolder, and you don’t need to be a PCB expert in using it. It’s affordable and only requires a few tools. However, the desolder wick method isn’t without drawbacks. 

Pros

The best advantages to a desoldering braid are its ease of use and affordability. You don’t have to maintain the braid because you throw it out once you’re done. These are the desolder wick method’s most significant advantages: 

• Affordable
• Easy to Use
• Does Not Require Maintenance
• Disposable

Cons

Desolder wicks are a great way to remove solder from a PCB, but it still comes with drawbacks. Firstly, it’s not reusable. If you plan on desoldering many electronic components, you’ll go through a lot of wicks, and the cost will go up as you have to purchase more. Also, if you don’t desolder correctly, you risk damaging the entire circuit board. Desolder wick method cons include: 

• One-Time Use
• Risk of Damaging Circuit Board
• Need to Use Correct Width to Avoid Issues

Solder Sucker/Solder Pump Method

A soldering pump is exactly what it sounds like. Also known as a solder sucker, you suction – or suck – melted solder using a handheld pump tool. The solder pump method is a little more involved than the wick method but is more effective at removing a lot of solder at once. 

How to Use a Solder Sucker or Desolder Pump

Before you can use a solder pump, you need to prime it. All you need to do is press the plunger down until you hear it lock. Press the release button to test the plunger. It should move backward and create a suction effect. Once your pump is primed and prepped, you can desolder your circuit board in a few steps: 

1. Use a soldering iron or another heated air source to melt the solder. 
2. Placing the solder pump’s tip as close to the solder as possible, press the release button. Ensure you keep the pump’s tip steady and in place as the pump suctions the melted solder. 
3. Repeat until all solder is removed from the component and circuit board. 
4. Using pliers, remove the part from the motherboard. 

Pros and Cons of the Solder Sucker Method

Solder pumps are cheap and easy to use. When used correctly, it leaves a smooth area for you to install a new component. There aren’t many steps, but you may need to repeat the process to remove all of the solder effectively. As with any desoldering method, there are pros and cons to using a solder sucker. 

Pros

Solder suckers are cheap and easy to use. It only requires two tools: the pump and a soldering iron. It’s the best method for removing a lot of solder at once, particularly on large components. These are the top advantages to using a solder sucker: 

• Affordable
• Ideal for Large Amounts of Solder
• Suitable for Desoldering Through-Hole Pieces
• Leaves Smooth, Empty Areas for New Components

Cons

While the pump’s tip is relatively small, its body is large, making it challenging to desolder small components. Also, this method doesn’t always desolder all that you’re trying to remove. You may have to repeat the process on the same piece of solder before you remove all of it. These are the most significant drawbacks to the solder sucker: 

• Not Ideal for Hard-to-Reach Solder or Small Components
• Risk of Damaging the Circuit Board
• Doesn’t Always Remove All Solder

Conclusion

For experts who work a lot with circuit boards or need to replace, repair, or recycle pieces, it’s essential to know how to desolder a PCB. There are numerous ways to desolder, but the most common methods PCB manufacturing companies use are using a desoldering braid or a solder pump. 

Both methods are easy and affordable. However, the solder pump is more effective on larger amounts of solder while a wick is better for smaller components. Whichever method you decide to use, both will effectively desolder your motherboard.