Would you like to know how to remove solder?
Circuit boards require care when mounting and removing components from them.
But, while attaching electronic components on a PCB using a soldering iron is effortless, stripping off molten solder is quite challenging.
Nonetheless, that shouldn’t be the case anymore, as, with this guide, you can confidently take up a desoldering job and do it perfectly.
Now let’s get right into it immediately and explore the details of removing unwanted solder.
What is Desoldering?
It is a simple process that entails dislodging the formerly connected electronic parts and molten solder from the surface of a PCB.
Also, it is a heat-intensive process, primarily dealing with solder joints firmly attached to the surface.
However, it is easier with the right tools and skills than you think. Below, we’ll look at it in detail while highlighting the best tool to use in different scenarios.
What Are the Tools Required for Desoldering?
Before embarking on a desoldering process, assemble the tools below, and everything else will be a breeze.
- Desoldering braid/ Actual solder wick
- Removal alloys
- Desoldering bulb
- Soldering Tweezers
- A heat gun
- A vacuum desoldering tool
- Removal flux
- Soldering stations/ power desoldering station
Ways to Remove Solder
Let’s explore the eight major precise techniques to remove solder from PCBs.
Braid Desoldering Method
- First, you need a soldering braid wider than the joint you want to dislodge. Also, you need a clean soldering iron, so ensure it is thoroughly clean from the deposits from the previous soldering job.
- Next, lay the desoldering braid on top of a perforated solder joint (you must make the hole earlier) and ensure it covers its entire surface.
- Finally, place a hot soldering iron at the point of contact of the joint with the soldering braid. This will heat the joint, rendering it molten. Wipe it off once it is well hot, and take on the next joint you want to remove.
- The soldering iron and desoldering braid must be removed simultaneously lest the latter cool, causing the molten solder to solidify again.
Desoldering Pump Method
A desoldering pump.
Are you having challenges accessing a desoldering braid? Worry no more; as with this technique, you don’t require it as long as you have a desoldering pump. How?
- Adjust your solder pump’s spring to the proper positioning, warm your solder iron to a high temperature, and place it on the joint to melt it rapidly.
- Next, lay the cheap desoldering pump on the molten solder and click the sucking button, and with one thrust, it will be sucked away.
- Once done, do the same to the other joints you want to remove.
Iron Desoldering Technique
The procedure is the same as for the desoldering pump methods. Here, you’ll have a desoldering iron with a built-in pump that works like the above.
Hence, to use it, heat the iron to melt the solder then its inbuilt suction pump will suck it away.
Heat Gun Desoldering Method
A man with a heat gun.
A heat gun can do wonders in removing solder. Clean up the circuit board section where you want to remove the solder.
Next, switch on the heat gun and direct its tip onto the solder surface to induce melting.
Molten solder is easy to remove; you simply need a tweezer or a pair of pliers to peel it off.
Hot Air Rework Desoldering Technique
Desoldering a PCB.
The principle of a hot air soldering station is similar to that of the methods we have discussed above. Nonetheless, this one has good precision, given that it primarily allows you to choose the appropriate nozzle depending on the solder joint size.
- Allow the decent-quality soldering station to warm up after switching it on. Next, set the airflow and temperature above the solder joint’s melting point to rapid melting.
- Before placing the nozzle on the joint, apply paste flux. Next, run the nozzle above the joint, and the solder will melt after some time.
- Finally, remove the molten solder with pliers or lab tweezers.
Compressed air desoldering Technique
We advise you to do safety gear, especially goggles because this technique is explosive and causes the solder joint parts to fly all around the area.
To use it, apply a hot soldering iron on the joint for melting. Next, place the compressed air pump on the molten solder, and it will expel it from the surface.
Tweezers Desoldering
Desoldering tweezers are specialized as they feature a soldering station. You can still use ordinary tweezers, but in this case, you will need a soldering iron.
- Place the hot tweezers on the solder joint and melt the solder, then pick it up from the surface using their tips.
- The desoldering tweezers technique is most suitable for removing delicate components from the circuit board. Also, they are effective when dealing with Heat-Sensitive Components or when you don’t want the heat to affect the adjacent components on the PCB.
Hot Plate Desoldering
A hot plate.
Finally, you can use the conventional hot plate to remove breadboard components and solder bridges from a PCB. However, recovering the parts is challenging as the apparatus heats the entire surface.
- First, heat the heat plate to a temperature high enough to melt the solder joints. Next, plate a metal surface on the hot plate to act as the heat transfer medium between the hot plate and the circuit board.
- Once the solder melts and you remove the parts, use a desoldering braid and iron to remove the solder bridges.
How to Remove Solder from Circuit Boards?
Flex-printed circuit board with the copper layer.
Here are other methods to desolder circuit boards.
Grinding and Scraping
It is a simple and easy-to-execute technique, but it requires patience as you will take a lot of time before scraping off the solder from the entire circuit board surface.
The method involves using a scraping tool such as a kitchen knife to grind on the solder joint and remove it carefully. While time-consuming, this is arguably the best technique for desoldering novices.
Also, you can use it to remove just a few joints, and you don’t have any of the desoldering attire we listed above.
Machining and Milling
The method will save you time over grinding, but it takes work to execute for desoldering beginners.
Also, it may prompt you to use a microscope to get the details right, meaning it will take a significant chunk of your time.
Chemical Stripping
Removing solder from copper plates via the chemical method is easy owing to the unreactive nature of the metal element.
Nonetheless, there’s a chance that it may damage the components meaning that you need to apply a protective layer on the board before the striping process.
Micro Blasting
If you want to do large-scale desoldering, this is the ideal technique.
The blasting tool relays the explosive material on the PCB surface, which vehemently expels solder from the surface.
How to Remove Solder from Circuit Board Holes?
A printed wiring board for surface mount technology.
Removing the Soldier from PCB holes requires more tact than the above methods, specifically expelling protruding solder joints. The following are some ideal techniques for dealing with circuit board holes solder.
- First, as explained in the previous section above, you can use a desoldering pump or wick technique.
- Alternatively, apply a drill to gorge out the solder from the holes. Preferably the diameter of the bit should be smaller than that of the hole you’re drilling so that it can fit in.
- Finally, you can combine the methods discussed in this section for a clean job.
How to Remove Old Solder?
Failed solder joints.
Removing old solder from a circuit board is quite challenging because one of its properties is that it hardens over time.
Therefore, the conventional basic desoldering techniques will not work.
But still, there is a way around it. First, apply fresh solder on the surface of the old solder layer.
Next, place a hot soldering iron on the joint to prompt the merging of the two solder layers.
As they try to merge, both will melt, and you can now remove the solder using the techniques we have already discussed.
How To Remove Solder Without Wick?
The solder wick or desoldering braid.
What can you do if you cannot access a commercial desoldering wick? There are three main ways to approach this.
- First, the role of the wick is to transfer the heat from the iron to the solder bridge or joint, so anything with its properties will do the job. For instance, you can twist the strands of an electric wire to make a simple wick that works as efficiently as the commercial one.
- Alternatively, dip the conventional lamp wick in solder flux to create a desoldering wick.
- If you can access neither of the materials, you can use a rod or any material, such as a graphite pencil, that is a great heat conductor but unlikely to merge with the solder joint.
How To Remove Solder Without a Soldering Iron?
Soldering Iron.
Take a case whereby you don’t have access to a soldering iron. What are some of the viable alternatives you can use to desolder?
- You will need a propane torch and an old screwdriver that you don’t mind tarnishing its steel bit.
- Place heat the bit to a melting temp above the solder’s melting point using the propane torch.
- Next, you must carefully apply the hot screwdriver on the solder joint’s tip to melt it down. If you don’t take caution, you risk damaging the Surface-Mounted Components adjacent to the joint you’re removing.
- Quickly remove the screwdriver from the melted solder, and it will come off with a bit of the solder that attaches to its surface.
- Next, heat the screwdriver to remove it from the bit and repeat the process.
How to Remove Solder Flux?
Electric soldering iron, solder, and flux.
There is no outright flux-removing technique, as everything depends on the type of flux you want to clear from the circuit board.
We recommend isopropyl alcohol if you’re dealing with no clean flux.
Alternatively, you can apply a chemical solvent to dissolve the material, such as the typical cleaning agent.
After application, gently scrub off the flux coating, preferably using a soft brush, then dry the surface with cotton wool.
Tips for Successful Solder Removal
Cleaning a circuit board.
- Always operate on clean circuit board surfaces, as working on such an area is easy. Also, you retain the integrity of your materials, flux, and desoldering chemicals.
- The size of the soldering iron tip matters. We recommend using small-size bits as they are excellent for heat transfer and don’t heat the adjacent areas.
- Don’t heat an area rapidly. Rather, it would be best to gently place the heating surface and then move the tip slowly around the area to melt the solder uniformly.
- Finally, we also recommend using liquid flux when desoldering as it is critical in preventing oxidation of the area. You’ll also experience improved heat transfer in its presence, which hastens the desoldering process.
Summary
We have got you covered in all your desoldering needs and depending on the tools you have at your disposal.
If you have had qualms about approaching a desoldering job, calm your nerves and take it up.
It is a seamless experience you can undertake even if you don’t have prior experience as long as you follow the insights we have covered in this guide.