PCB Cleaning Solutions: Tips on Removing PCB Soldering Flux

Need for "Printed Circuit Boards" in any and every electronic goods is invariably present. To better understand PCBs you can open Television panel from back and get a glance.

These are boards which are made of-

1. Laminates
2. Copper-Clad Laminates
3. Resin impregnated cloth
4. Copper foil

They primarily become physical support for various electronic components like, capacitors, diodes, resistors etc. They also are medium of electrically connecting these components in the required circuit to make the product function.

PCBs can come in various sizes and thickness and are holed. The different components which are interconnected in circuit are placed in these holes and connected to the circuit via- Solder.

Solder is a metal, with low melting point, used to connect two metals permanently without melting them. The process is termed as Soldering. Depending on the objective and place of joining components solder properties might vary. For example, if solder is used to connect circuit of electronic parts then it must have certain specific electrical characteristics and should be corrosion and oxidative resistant.

Soldering process usually leaves unwanted melted solder on the board, as the PCBs are very small in shape and size. These unwanted solders are termed as – Soldering Flux. Solder Flux removal from the PCB is must, to avoid any damage, corrosion and contamination. They are usually not water-soluble and need special treatment for removal.

Find below tips for removing PCB soldering flux-

1. Use of Brush: You may use paint brush dipped in isopropyl alcohol as Solder Flux remover and simply wipe them off the PCB. But not all can be removed by this method; hence you need various other things to perform flux removal.
2. Solder Flux Cleaner: There are various chemical solutions which can loosen the flux on the board and can then be rinsed out with distilled water.
3. Paint Thinner: You may even try paint thinners as Solder Flux Remover and soak the PCB in them. After some time take them out and rinse with water to remove the flux. You may need some brushing as well to clean.
4. Keep the board Dry: Always remember after rinsing with distilled water or with any solution you must completely dry the PCB to avoid any damage to the circuit or board.
5. Residual Sludge removal: Even after flux removal there are chances of "residual sludge". This can be due to the solution used. Therefore you must clean or rinse the board with water and use slight brushing.
6. Ultrasonic Cleaners: You may also use ultrasonic cleaners, primarily for PCB manufacturers, which are water based. While using one you must carefully read the product manual for proper and safe usage.

It is always advised to use solutions or remover which do not react with the components or corrode the PCB. Always use non-inflammable solvent-based solutions to remove water-insoluble solder flux.

Therefore before using you must thorough read the manuals of such solutions. Cleaning Solder flux can be simple and fast only when you act smartly and use correct methods and materials for cleaning.

Rohit Jain is well qualified and trained electronic Engineer, he has good knowladge and experience about electronic tools and equipments industry.