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Cleaning PCBs

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I have some hand soldered PCBs I want to clean up, I tried to remove the rasin and other sticky stuff of  the PCB using alcohol 96%, and Chemtronics Flux-Off VZ, but neither is working very well. After using the Chemtronics Flux-Off VZ, it seems now there is a sortof white filmly layer on the PCB :(

What is the best way to clean them properly. I tried using Aceton on a old board, but aside from the risk of dissolving the silkscreen, it did not seem to the work well either.



to be fair you didnt say the age / vintage of the pcb, when you get past 20 years, it always gets harder to clean, as the masking and silkscreen start degrading to a level where most cleaning products strong enough to lift flux start lifting them aswell,

i suppose if you dont end up finding anything, on some 30+ year boards, i have scrathed off the flux with a metal scribe and used some other lighter cleaner to tidy it up, but that gets into the region of how badly you want it to look nice,

Be careful getting any pre-made circuit board cleaner on your skin.
I accidentally sprayed my hand while holding a pcb and my skin turned red in that area for 2 months.

I dunno what it has in it, but it's not good for you.

You can use 96% ethanol, or methanol, or isopropyl alcohol. You need to apply the solvent liberally and use a stiff bristled brush to work the flux loose before rinsing it away. It won't just dissolve all by itself, it needs a bit of help.

Oh, and as Psi said, wear rubber gloves to protect your skin.

Is the resin that remains due to a liquid flux you are using or is it the solder's core?  You might have to switch to a different flux and/or a different solder.

I use a so-called water soluble flux which is really easy to clean.  Some of the solder I use has a rosin core which is a little tougher to clean.  When I can, I use the water soluble flux and a solder that has no core.  I can clean a board up using just water when I do this.

Just for the record, once I'm finished soldering with a rosin core solder, I use isopropyl alcohol and an old toothbrush to clean the board.  (Yes, I should be using an ESD safe, $50 brush.  blah, blah, blah...)  I dip the brush in the alcohol and scrub the board 'liberally', as Ian says.  I then rinse the board under running water (just so long as there are no components that will have an issue with that.)  A second cleaning is sometimes necessary.

After wiping off the excess water with a paper towel I then I use an old hair dryer or my hot air station to dry the board.


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