PC board defluxing and washing

[calexanian]

I have been looking for a solution for years. Perhaps somebody out there already has it. We need a way to deflux, and also clean boards that some back in for service. As it is now we just use flux off, or other such chemicals but it is rather wasteful. Years ago we could use vapor units but California no longer allows them. I have been trying to think of some contraption that would wash the boards, then I could distill the dirty solvent back out. Perhaps under vacuum to reuse the cleaner. Any thoughts? We still use RA flux in most of out products, and have for 34 years...

[gbyleveldt]

This:
http://www.electrolube.com/products/cleaning/detail.html?pid=26&section=1
and 3 minutes in an Ultrasonic cleaner. Rinse, dry, done.

And after 80 boards over a one month period it still seems rather effective, although there's a fair amount of gunk forming at the bottom of the cleaner

[calexanian]

Thanks for trying but that product is not available in the U.S.and dose not meet our local environmental requirements (The most stringent in the entire world to be exact here in the San Joaquin valley.)

[nctnico]

Bio-ethanol works OK for removing flux. Simple Green works great for cleaning dirty boards.

[mazurov]

Hot IPA combined with ultrasonic bath. If your rosin is badly burnt, like after lead-free rework, some mechanical cleaning with old toothbrush may be necessary on fine-pitch parts. I use two 30 min. runs in 60-70C ultrasonic - first using 70% USP grade grocery store IPA (which can be used several times), second with 99% IPA (which can also be used several times depending on what you're making). Compresses air cleaning and toothbrush between 1st and 2nd runs. Works very well. You can recover IPA with simple distillation setup using very little electricity; this is also a way not to drain lead into the sewer, if you're still using lead in your process.

[Napalm2002]

I know a guy who works for NASA that says that they clean their boards with straight everclear. Ie pure grain alcohol. I was also told that a big company used to put their boards in a dish washer...

[calexanian]

The hard part will be reusing the fluid. Some kind of distillation method will be required every now and then.