How to clean PCBs of conformal coating

Thread Starter

Malatesh Patil

Joined Dec 2, 2016
3
Could anybody help us on how to clean the PCBs with Conformal coating. We are using IPA in Ultrasonic Dip for cleaning the PCBs for after repair quality. Can we use Acetone in Ultrasonic Dip, Thanks in Advance, reg
 

jpanhalt

Joined Jan 18, 2008
11,087
I have used acetone, MEK, and lacquer thinner in ultrasonic cleaners with no problems. There is, of course, the fire danger. There is also a chance of accelerating a chemical reaction that you would not normally see without such mixing. I would not suggest using some halogenated compounds (e.g., methylene chloride or chloroform) in an ultrasonic cleaner to increase the solvent power. Perchloro-cleaning agents may be OK, if you can get them, but have a greater health risk associated with them.

As for whether any of those solvents will remove the conformal coating you have, that depends on the coating. Many are acrylic lacquer-based, and those solvents should work. Some may be epoxy or other chemistry and would not be very easily removed.

John
 

Thread Starter

Malatesh Patil

Joined Dec 2, 2016
3
I have used acetone, MEK, and lacquer thinner in ultrasonic cleaners with no problems. There is, of course, the fire danger. There is also a chance of accelerating a chemical reaction that you would not normally see without such mixing. I would not suggest using some halogenated compounds (e.g., methylene chloride or chloroform) in an ultrasonic cleaner to increase the solvent power. Perchloro-cleaning agents may be OK, if you can get them, but have a greater health risk associated with them.

As for whether any of those solvents will remove the conformal coating you have, that depends on the coating. Many are acrylic lacquer-based, and those solvents should work. Some may be epoxy or other chemistry and would not be very easily removed.

John
Thanks Jpanhalt, Thanks, What is lacquer thinner, what is the Chemical Name & Commercial Name?
 

jpanhalt

Joined Jan 18, 2008
11,087
Lacquer (https://en.wikipedia.org/wiki/Lacquer ) is a type of finish. It was commonly used on cars until better finishes were developed. Today it is used mostly on wood and in art. Acrylic conformal coatings can be classified as lacquers, as they harden by solvent evaporation.

For some applications, lacquer needs to have its viscosity reduced with a thinner that is usually composed of organic solvents which may include acetone, ethyl acetate, MEK, butyl acetate, some alicyclic and aromatic hydrocarbons and so forth. In other words, it is a moderately strong solvent with a higher boiling point than acetone alone. That solvent mixture can be used to removed hardened lacquer as well as other finishes. Reducers for automotive synthetic enamels are similar, but can easily be confused with another type of thinner for enamels that will not work. The term"paint thinner," which is commonly used to describe thinners for household enamels, is mostly aliphatic hydrocarbons (e.g., mineral spirits or VM&P Naptha). It's solvent strength is inadequate to dissolve and cleanly remove any conformal coating I have seen.

John
 

ComortleD

Joined Jul 6, 2017
2
Hi
I feel like I can help you in this matter. Using acetone is good , but it should be mixed with some agents , in order to make the cleaning process better. I faced a difficulty when i tried to clean the pcb with conformal coating in one of my project works.

Some types of plastic dissolve in acetone and some electronic components are partially made of plastic. Therefore washing boards with these components on them in acetone can cause damage to them.

There are good companies in Toronto which offer solutions for Conformal coating issues. I had taken help from such a company and that was very useful. They will suggest you some better solutions to clean the pcb, if you specifically mention the components used. Hope your issue is resolved soon.
 
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