Ultrasonic cleaner size: 10L vs 6L

[tooki]

The frequently observed "white residue" probably requires a saponifier (alkaline) remover in water.

Were you secretly thinking of dish soap when you typed this? If so, whisper it in my ear and I'll add it to my solution next time.

As I already told you: dish soap is NOT a saponifier! Stop fixating on dish liquid, no matter what you've seen "everyone" do.

Automatic dishwasher detergent is likely alkaline enough to do the job, but at the expense of possibly being too corrosive. Aqueous, saponifier-based flux removers/PCB cleaners are designed to include corrosion inhibiters and generally be suited for electronics.

[tooki]

As noted above,yes, hand soap.  And the brass brush has to be very soft, like camel hair almost.

For cleaning watches perhaps. But the question is about cleaning PCBs, and for that, hand soap or dish liquid is pointless -- at least if flux is to be removed.

[CaptainBucko]

FYI Attached is the datasheet and SDS of ChemTools Kleanium Printed Circuit Board & Electronic Parts Cleaning Solution which I have been using with success in my UltraSonic cleaner.

[jpanhalt]

There are lots of similar water-based flux removers with saponifier.  The ChemTools product has the same basic formula of a glycol ether and ethanol amine or other strong base.  2-butoxyethanol (and others) is used in other removers and goes by a trademark class name of cellosolve.  The later is used at a final concentration of about 10% .  I didn't see at first glance whether the ChemTools product is used neat or diluted.

[CaptainBucko]

I didn't see at first glance whether the ChemTools product is used neat or diluted.

They say to use it neat and that is all that I have done. I only put a small amount inside a plastic zip lock bag with the item I want to clean, and then place the sealed bag in normal tap water in the cleaner.

[SolderOcelot]

Flux is not my problem by the way. I solely use the ultrasonic cleaner for liquid damage (as in tap water touching electronics while they're powered on) and so to clean the white (iron?) and green oxidation (copper). I don't know if that makes a difference in the recipe. I guess water + saponifier + surfactant is still the way to go?

[jpanhalt]

If it's oxidative damage to a metal, alcohols are not very good solvents for that.  Water + surfactant/detergent is better.  I wouldn't try to get too deeply into the chemistry.  There are basically two choices water-based and non-aqueous.  IPA and ethanol will both have some water, unless you use absolute versions or something like E85, which I do not recommended, but I would consider those alcohols as non-aqueous.  Glycol ethers that are in all of the aqueous flux removers have special solvent properties.  Using an aqueous flux remover is generally safe and a good cleaner even if flux residue isn't the issue.

There is nothing wrong with starting with IPA, though.

[SolderOcelot]

@jpanhalt:
Interesting, for so long I believed in IPA being undisputed solution for this use case and it was possibly not true.

Out of curiosity.. Where did you gain this knowledge around solvents and cleaning? Was it something you picked up in hobbies or was it essential to your work?

[jpanhalt]

@jpanhalt:
Out of curiosity.. Where did you gain this knowledge around solvents and cleaning? Was it something you picked up in hobbies or was it essential to your work?

Grad school plus decades of experience.  It wasn't necessary to my work, but as they say, you can take a chemist out of the lab but you can't take the lab out of a chemist.

[SolderOcelot]

but as they say, you can take a chemist out of the lab but you can't take the lab out of a chemist.

Of course not, that would be reverse entropy