What is PCB flux and how to remove PCB flux after soldering

What is PCB flux and how to remove PCB flux after soldering

Table of Contents

What is PCB flux?

PCB flux is a chemical cleaning agent that helps to remove oxidation from the surfaces of the metal parts being joined. It’s applied to the metal parts before they are joined, and provides a protective layer between them, preventing corrosion.

PCB flux comes in several forms: liquid or paste, depending on your preference; however, it can be difficult to remove both types of flux once they’ve been applied, (its best not to use too much at once). 

If you’re experiencing trouble removing, solder residue after soldering two pieces together, try soaking one side of one piece in alcohol-based hand sanitizer first before applying flux onto both sides again. This should help clean off any residual solder without having to use harsh chemicals like baking soda or chlorine bleach which may damage other components nearby!

Types of PCB flux

PCB fluxes come in a variety of different types.
The three main types of PCB flux: are rosin flux, water-soluble flux, and inorganic flux.

1. Rosin flux
Rosin flux is a rosin-based flux that works best in removing foreign particles from the metal going through the PCB soldering process. It is usually used with tin and lead – it will not work well with other metals, such as aluminium. This type of flux will be water-soluble, which means that it can be applied to both wet and dry surfaces without causing damage. This can prove useful for soldering through different materials such as plastic or glass, but it also makes it more likely that you’ll have oxides in your soldered joints.

2. Water soluble flux
Water soluble flux is quicker and stronger than rosin flux; it’s also good for soldering outcomes because of its ability to remove oxides and create a clean surface for the soldering process. Water soluble flux can be extra aggressive compared to rosin flux, so you should use caution when working with it around flammable materials (like plastics). Be careful when using a soldering iron on any surface containing water-soluble flux; it could cause uneven heating or cause a flare if too much heat is applied at once!

3. Inorganic flux


Inorganic flux works well with strong acidic and alkaline soldering fluxes. It’s usually used with copper and aluminium, which are both good conductors of electricity. Inorganic flux is often used in industry because it can withstand high temperatures without breaking down.

The application of PCB flux in different types of PCB production

PCB flux is a chemical compound that helps the solder adheres to the surface of your PCB. It can be applied manually using a solder pen, or it can be used in some automated processes.

● Manual hand-soldering

It simply heats the wire onto the surface with a soldering iron. Once it is hot enough, apply a small amount of flux on top and allow cooling. This will help prevent any oxidation of the board; it’s even better if you pre-clean your board before applying flux.

● Wave soldering

Spray the flux onto your PCB before soldering any components. Once they are all soldered, remove any oxide layers from between each component and clean the board again with soap and water before applying additional flux.

● Reflow soldering

Use solder paste instead of just plain old PCB flux. Solder paste is a combination of powder made up of metal particles and sticky liquid flux that has a consistency like putty or clay-like substance. The solder paste will fill in all the gaps between the components and the PCB, thereby creating a strong bond.

How to use PCB flux?

PCB flux is the most important thing you need to solder electronic components. It’s a substance that reduces smoke and makes your work easier.

solder electronic components
Here are some steps to follow:

1. PCB cleaning is a process when clean the metal contact with a good solvent such as alcohol or acetone. This will remove any grease or other residue from the surface, which can interfere with your solder job.

2. Apply an even coat of the flux to the surfaces of each component you’re soldering, making sure not to cover any of its edges or base.

3. Place the components on top of each other so that their tips touch, and heat them until they become molten (about 20 seconds for small parts, about half a minute for larger ones).

4. Remove them from the board using tweezers or your fingers, then add new solder paste on top of each one before putting it back on top of your board (this will ensure that they stay connected).

5. Repeat steps 3-4 until all components have been soldered.

Why PCB flux has been used in soldering?

Soldering is a process that involves placing a lead or wire onto another surface, heating it to melt the solder and then placing the component onto this molten metal. For this to happen, there has to be an electrical connection between the two components.

PCB flux is a type of cleaner that is applied to the surface of a PCB. It helps remove oxides and impurities, which are then cleaned away. PCB flux also tends to wet the surface of the PCB, making it easier for solder joints to connect. This makes it an excellent choice for soldering or wetting circuits before soldering them together.

Fluxes are also good for de-oxidizing metals and removing oxide from their surfaces. As long as there are no impurities on the surface being cleaned, flux can be used safely and effectively.

Why it is necessary to remove PCB flux?



PCB flux is a cleaning agent that helps remove oxidation from the surface of a board. It also has other functions, like preventing corrosion and corrosion-related defects in electronic devices.

However, PCB flux can be harmful to the environment as it contains chemicals that are not suitable for use in landfills or other environmentally sensitive areas like oceans and rivers. There can be residue left behind after removing the solder from each component before soldering them together again.

This residue could eventually cause issues such as corrosion when exposed again later on down the line because these types of materials aren’t easily cleaned up by hand washing methods like soap would do – instead, they require specialist equipment which costs money just so we don’t accidentally ruin our creations when trying something new here at home too quickly after finishing up one project before moving onto another project within only minutes!

How to remove PCB flux after soldering?

The most common method of removing PCB flux is to use a solvent in a well- ventilated working space.

1. Remove PCB flux by using isopropyl alcohol
If you want to remove PCB flux, use isopropyl alcohol. It is used to remove the solder and other materials from surfaces and can be used as a flux replacement when needed.

2. Remove PCB flux without using alcohol
There are many ways to remove PCB flux without using any type of liquid solvent or cleaning product. You can use a dry brush or chisel tip soldering iron to clean up the area where the copper pads are located, or you can use a hair dryer on high heat for 2 minutes to heat the surface so that it will remove any solder residues from the board itself.

solder residues from the board itself

3. Remove water-soluble PCB flux
With water-soluble flux, you can simply use warm water to remove it from your PCB. Just soak the board in a bowl of warm water for about 30 minutes, and then gently scrub off any residue using a soft-bristled toothbrush or an abrasive pad.


PCB flux is a chemical compound used for soldering. It’s important to remove it after soldering because it can cause oxidation, which will damage your board.

PCB flux is a special kind of chemical based on the tin. It is used in soldering to clean the solder and remove oxidation. When the PCB board has been soldered, it is necessary to remove the flux so that you can release the power of your circuit board and make sure that your product works properly when you use it.

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