Professional PCB Manufacturer

China PCB Manufacturer

How to Remove Flux from PCB? 6 Easiest Ways

Views: 327 Author: Site Editor Publish Time: 2023-02-20 Origin: Site

What Is Flux?

Flux is a chemical cleanser that is extremely popular in the soldering of printed circuit boards globally. It assists in giving the board a spotless, corrosion-resistant surface so that the solder may successfully make a secure connection. Moreover, it stops oxidation, which can result in the failure of electrical connections.

This is important for PCB companies to learn about the ways they can remove flux PCB conveniently.

What Are the Types of Flux?

1. No-Clean Flux: This flux is only used in selective or wave soldering and does not require to be cleaned after soldering. It is frequently constructed of rosin or resin mixed with halide activators and utilized in surface mount and through-hole components.

2. Water Soluble Flux: This particular flux is used in wave soldering and after soldering, it needs to be well cleaned. It is typically composed of an organic acid chemical combined with an activator and is used in through-hole components.

3. Organic Acid Flux: This kind of flux is utilized in wave soldering and needs to be thoroughly cleaned after soldering. It is typically composed of an organic acid compound combined with an activator and is used in surface mount as well as through components.

4. High-Temperature Flux: The flux used in reflow soldering doesn't need to be cleaned up after soldering. It is typically composed of an organic acid substance combined with an activator and is used in surface mount components.

Why Is It Important to Remove Flux?

Flux residues on the printed circuit board are also fairly well washed off with isopropyl, wood alcohol, isopropanol, acetone-based nail polish remover, and an alkaline solution with a 5% surfactant content.

There are also fluxes that leave no residue after use, but they give the board some haze, making it difficult to examine the radio components in detail if necessary. Therefore, it is recommended to wash off the remains of even such a “safe” flux.

In any case, in order not to form an oxide film, first of all, organic, rosin, and synthetic fluxes should be washed off. The composition can always be found on the packaging. At the same time, remember that rosin is the most difficult to remove from the board, so it is better for novice radio amateurs to avoid their use.

7 Reasons to Remove Flux

1. Flux residue over time can corrode parts.

2. Circuit board shorts can be brought on by flux residue.

3. Electrical noise can be caused by flux.

4. Flux residue has the possibility of damaging delicate components.

5. Remaining flux might draw dust and grime.

6. Flux can result in components not sticking to the board well.

7. Subpar solder junctions may result from flux.

What Are the 6 Ways to Remove Flux Without Using Alcohol?

1. Remove the flux residue with a brush or vacuum.

2. Wipe the flux away using a moist cloth.

3. Obtain flux removal solution, such as rosin, flux remover, or cleanser with a citrus base.

4. To remove the flux, clean with a gentle toothbrush.

5. In order to get rid of the flux, use a solvent such isopropyl alcohol.

6. Heat the flux using a hot air gun to make it simpler to remove.

How to Clean Flux Residue?

Flux residue can be challenging to remove, but it is possible with the correct equipment and methods. The steps to remove flux residue are as follows:

1. Gather the important equipment. A lint-free cloth, rubbing alcohol, cotton swabs, and flux remover are all required.

2. Use the lint-free cloth to remove any extra flux residue first. In order to prevent scratching the surface, be careful to move in soft, circular motions.

3. You can also use rubbing alcohol to gently remove any remaining residue. Apply the rubbing alcohol to the affected area with a cotton swab. Using the lint-free cloth, remove the leftover material.

Explain in Detail How to Clean the Board After Soldering

1. Remove any flux residue and other pollutants from the PCB by wiping it down with a lint-free cloth and rubbing alcohol.

2. To get rid of dust and debris, use a vacuum cleaner if the PCB contains any substantial components.

3. Air-dry the PCB or dry it off with a lint-free towel.

4. Check the board for any faults or other issues and, if necessary, fix them.

5. Use conformal coating to insulate the PCB from corrosion-causing moisture, dust, and other elements.

6. Check the board's functionality one last time to ensure appropriate operation.

How to Clean Flux Without Isopropyl Alcohol?

1. you can use a soft, lint-free towel to wipe flux residue away.

2. Add some liquid dish soap or mild detergent to a pitcher of warm water.

3. Dip the towel in soapy water and clean away any leftover flux residue.

4. Remove any soap residue by rinsing the towel in fresh water.

5. To remove any leftover flux residue, wipe the area with a cotton swab dipped in isopropyl alcohol.

6. Cleanse the area with water, then dry it with a soft, lint-free towel or cloth.

Why You Should Clean the Flux Off of the PCB?

Yes, it is important to remove the flux from a PCB. Flux is a substance that aids in the solder's adhesion to the board during the soldering process. If left on the circuit board, it can function as an insulator and cause issues with the circuit. Also, it might draw dust, moisture, and other impurities that might result in corrosion or shorts.

The circuit board must be clear of pollutants that could harm it and the flux must be removed in order for the circuit to operate as intended.

How Can I Quickly Remove Flux?

Flux remover, sometimes referred to as flux cleaning, is a chemical substance developed to dissolve and clear flux, and it can help you get rid of it swiftly and safely. You can use a brush, cloth, or spray can to apply flux remover. When using the flux remover, be sure to read and abide by all safety precautions on the container.

Which Flux Remover for PCBs Is Best?

An excellent flux remover is available at Radioshack.

I have discovered that the majority of flux removers lack the abrasiveness necessary to completely remove the flux. As a result, a small layer of flux residue remains that is resistant to the majority of flux removers.

How is the Printed Circuit Board Affected by Flux?

A printed circuit board might experience harm from flux if it is not properly removed after soldering. Electrical shorts, shoddy connections, and other reliability concerns can result from flux residue corroding and harming the copper traces and other components on the board.

Flux can also make tracks and pads brittle, which can result in cracking and other types of damage.


We strongly recommend that you do not rub the board with a rag, as you can damage the leads of the radio components, which will lead to their displacement or malfunction due to signal loss.

This method is also suitable in case you went too far with the amount of flux when installing components, after soldering, and a flux spot was left at the work site. If it is not removed, the place will quickly darken, and the surface of the board may eventually lose the top layer at the point of contact.

About The Author

I am the Engineering and Sales supervisor working in Victorypcb from 2015. During the past years, I have been reponsible for all oversea exhibitions like USA(IPC Apex Expo), Europe(Munich Electronica) and Japan(Nepcon) etc. Our factory founded in 2005, now have 1521 clients all over the world and occupied very good reputation among them.


Contact Us



Company Name