| Electronics > Repair |
| I*really* want to remove Kester 44 flux - what do I need to buy? |
| << < (4/6) > >> |
| jpanhalt:
--- Quote from: eetechTom on July 18, 2024, 01:52:04 pm ---I have typically used a flux remover such as MG "Flux remover for PC boards", followed by a IPA rinse. I see the MG product contains Ethanol, isopropanol, and ethyl acetate. --- End quote --- That's the difference between water-based removers and nonaqueous removers. When you get a white residue, like between the pins of a fine-pitch IC, you will appreciate what Kester has said about needing a saponifier. The chemical compositions of both versions of flux remover are quite similar across the spectrum of manufacturers. There are subtle differences in formulations and differences in naming the very same thing. |
| joeqsmith:
I use ProClean. https://www.microcare.com/en-US/Products/Alcohol-Enhanced-Flux-Remover-ProClean |
| Calambres:
Mr. Carlson swears by "Lacquer Thinner" for flux removal. The problem I find is that what it is known for that in North America is apparently not the same here in Europe, that is, I do not know *exactly*what that "lacquer thinner" is: turpentine?, white spirit? anything else? |
| tooki:
--- Quote from: macboy on July 18, 2024, 01:17:41 pm --- --- Quote from: tooki on July 18, 2024, 07:20:06 am ---For what it’s worth, despite the fact that tons of people do so, Kester itself says that “IPA will not clean the residues off the surface of the circuit board after the soldering process.” This suggests that invisible ionic contaminants or activators remain (which otherwise would have remained entombed in rosin). Probably no big deal for most circuits, but still, I think it’s wiser to use flux remover. --- End quote --- Most or all solvent based flux removers will do no better. Salts don't dissolve into alcohols or petrochemical solvents. Kester specifically recommends a saponifier, a water based cleaner that will literally convert the organic rosin into soap, and will wash away the halide salts. The ZEP floor finish stripper recommended above is supposedly such a product and is available to consumers. When using the paper towel method I described above, I don't get any visible residue left behind (especially not that white gunk commonly encountered) and for most purposes of mine, that's good enough. I absolutely agree that for sensitive precision circuits, a better cleaning is needed. --- End quote --- In my experience, mixed-solvent based flux cleaners do a far better job than straight IPA or ethanol. The fact that straight IPA in an ultrasonic bath produces far better results than when hand cleaning suggests that the salts are somewhat soluble in IPA, and that redeposition (or just adhesion) are the real issue. |
| johansen:
--- Quote from: tooki on July 18, 2024, 11:04:36 pm --- --- Quote from: macboy on July 18, 2024, 01:17:41 pm --- --- Quote from: tooki on July 18, 2024, 07:20:06 am ---For what it’s worth, despite the fact that tons of people do so, Kester itself says that “IPA will not clean the residues off the surface of the circuit board after the soldering process.” This suggests that invisible ionic contaminants or activators remain (which otherwise would have remained entombed in rosin). Probably no big deal for most circuits, but still, I think it’s wiser to use flux remover. --- End quote --- Most or all solvent based flux removers will do no better. Salts don't dissolve into alcohols or petrochemical solvents. Kester specifically recommends a saponifier, a water based cleaner that will literally convert the organic rosin into soap, and will wash away the halide salts. The ZEP floor finish stripper recommended above is supposedly such a product and is available to consumers. When using the paper towel method I described above, I don't get any visible residue left behind (especially not that white gunk commonly encountered) and for most purposes of mine, that's good enough. I absolutely agree that for sensitive precision circuits, a better cleaning is needed. --- End quote --- In my experience, mixed-solvent based flux cleaners do a far better job than straight IPA or ethanol. The fact that straight IPA in an ultrasonic bath produces far better results than when hand cleaning suggests that the salts are somewhat soluble in IPA, and that redeposition (or just adhesion) are the real issue. --- End quote --- Its just dilution, the ultrasonic works because you have to fill it with a liter or 3 of liquid. Company i work for has two ultrasonic cleaners, one for prewash and you change the ipa when it turns pink from loctite, and the final wash which gets dumped into the pre wash on a regular basis. Evaporation makes most of thr ipa disappear. Final wash gets changed when you start to notice a sheen on the boards. |
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