Ultrasonic cleaners.

[paulca]

I decided to buy one of these.  Same model more or less to the one Great Scott demoed.

I didn't buy any cleaner, not yet.  I put tap water in it, dumped in a cup full of IPA and put a PCIe M.2 card in it, I found it on the floor under a spilt bottle of "Vape juice". So it was sticky and literally covered in fluff, cat hair and all manor of things.  The label had come off the M.2 SD drive exposing the ununsed ball grids.

I am NOT putting that into a PC.  However.  10 minutes in the ~5% IPA water bath in the cleaner and ... it looks fine.  I gave it 15 minutes in the oven at 50C and then a rinse and dab with neat IPA.  I might put this in the PC later now.  I have no idea what that SD actually is.  Im curious.

So.  Tap water is probably the worst of it.  I expect my first "buy" should be deionised water, either for car batteries or clothes irons.

I did notice on 2 of my hand soldered boards that it cleaned them, but it did not restore the "shine" leaving the same slight dulling of the dried in flux.  I assume what I might be better with there i actual PCB flux cleaner for ultrasonics, from an actual suppiler not Amazon?

Also... tell me your tips.. how long.. is 50*C better then room temp?  Is the 50C oven air dry necessary?  Is the IPA bath neccessary, should I do one, not both?

EDIT:  As a post mistake safety advisory, reminder.  IPA fumes are intoxicating.  Experiencing any level of IPA intoxication should be taken extremely seriously and fresh air obtained.  Use a powerful fan and open window and avoid getting too close to drying IPA wet boards!  The seriousness if in the dose delay... IPA vapour to the lungs goes straight to the blood, straight to the brain.  You can go from 100% sober to absolutely "lashed" in seconds to dead - literally in glue sniffer solvent abuse territory.

[tszaboo]

You don't put IPA in ultrasonic cleaner as it can set your house on fire.
I haven't figured out yet what would be the optimal way of cleaning soldering flux with it yet.

[paulca]

You don't put IPA in ultrasonic cleaner as it can set your house on fire.
I haven't figured out yet what would be the optimal way of cleaning soldering flux with it yet.

Yes.  IPA fumes are also extremely flamable.  For some reason the device got located in the kitchen, either "Well it's a cleaning thing" or "Looks like it makes fire".  Either way its a hazard.

I was told (by google bot) that distilled water + 5%-25% IPA was the defacto method.  Fire hazards asides.

I checked that again and the 5% is probably at the "wiser end" of things.  The risk is the evaporated alcohol in the chamber if you put the lid on can "detonate".   The ratio dillution matters a lot.  "Pure" IPA is asking for fire from even the slightest spark anywhere and it's a cheap device.  If pure IPA is required, the recommendation is to place the thing needing cleaned inside a sealed bag with IPA and place that in the cleaner,

Still I did correctly place it on a kitchen bench with a hood and an easy reach fire blanket.

[chilternview]

Allendale ultrasonics is the place I've used in the UK.

https://www.allendale-ultrasonics.co.uk/collections/flux-removal?utm_source=Google&utm_medium=cpc&utm_campaign=LD_PMax_Sales_AllProducts&utm_id=23236618447&gad_source=1&gad_campaignid=23621039247&gbraid=0AAAAAC3h_L_owJ4Y29Dh0_hiI6wlcFk9H&gclid=Cj0KCQjw16_UBhCqARIsAIdOaXznvyWmA353Rtgbf84YkbJ5w7FzpsO9zRhoZRetHC3wpqm2QlY771EaArsGEALw_wcB

[Zucca]

You don't put IPA in ultrasonic cleaner as it can set your house on fire.
I haven't figured out yet what would be the optimal way of cleaning soldering flux with it yet.

some user, I think was @tooki , reported to put the IPA+PCB submerged in a zip (closed of course) bag.
Then it in an ultrasonic cleaner without worrying about fumes.

[paulca]

You don't put IPA in ultrasonic cleaner as it can set your house on fire.
I haven't figured out yet what would be the optimal way of cleaning soldering flux with it yet.

some user, I think was @tooki , reported to put the IPA+PCB submerged in a zip (closed of course) bag.
Then it in an ultrasonic cleaner without worrying about fumes.

I seen that in a few searches, not specificall tooki, but using a sealed bag or vile with neat IPA and put that into the cleaner bath.  The vapour is contained and the bag is a spark barrier.

EDIT:  Still though.  It makes me think it's worth doing somewhere you can just walk away if it goes on fire.  like outdoors or in the garage.

[Benta]

Use distilled water instead of tap. It's cheap and you avoid calcium (and other) problems.

[tooki]

You don't put IPA in ultrasonic cleaner as it can set your house on fire.
I haven't figured out yet what would be the optimal way of cleaning soldering flux with it yet.

some user, I think was @tooki , reported to put the IPA+PCB submerged in a zip (closed of course) bag.
Then it in an ultrasonic cleaner without worrying about fumes.

Indeed!

If at room temperature, it's also OK to put alcohol in a glass beaker (plastic works but absorbs more energy) set into the bath of water. That at least gives you a "moat" of water around the flammable liquid.

IMHO the most important reason to use a bag or beaker is simply to reduce the amount of flammable solvent being used, plus the water right there if something should go wrong. (E.g. a leaky bag or a broken beaker simply means it gets diluted to a safe concentration.)


With that said, I now do most of my ultrasonic cleaning with either aqueous cleaners, or with pure water for water-soluble flux. ChipQuik's water-washable no-clean flux is kind of the best of both worlds, in that it's noncorrosive, but still water soluble. Heck, you barely need ultrasonic for it, it washes off readily in hot water!

[paulca]

With that said, I now do most of my ultrasonic cleaning with either aqueous cleaners, or with pure water for water-soluble flux. ChipQuik's water-washable no-clean flux is kind of the best of both worlds, in that it's noncorrosive, but still water soluble. Heck, you barely need ultrasonic for it, it washes off readily in hot water!

I think the specific PCB cleaner stuff might be my best bet.  Stuff sold for removing flux that isn't flammable.

My flux is a "No clean", so non-corrosive and IPA does dissolve it, but, it's still sticky even after a few IPA baths and soaking up immiedately, removal by repeated dillution.  It still ends up leaving a sticky film on the PCB that then collects lint and fibres from ... everything really.

More annoying.  When you pick an old project off the shelf thats covered in dust, blowing the dust off, doesn't work.  It's glued on by the flux.

Does water soluabe flux have any disadvantages?

[paul cotter]

Isopropanol is not that toxic, being somewhat more potent as an intoxicant than ethanol. It has been drunk by alcoholics when no other alcohol can be sourced but this is NOT a good idea. The effects of isopropanol are longer lasting than those of ethanol and it is metabolised by the liver into acetone which will be detected on one's breath.

[tszaboo]

With that said, I now do most of my ultrasonic cleaning with either aqueous cleaners, or with pure water for water-soluble flux. ChipQuik's water-washable no-clean flux is kind of the best of both worlds, in that it's noncorrosive, but still water soluble. Heck, you barely need ultrasonic for it, it washes off readily in hot water!

I think the specific PCB cleaner stuff might be my best bet.  Stuff sold for removing flux that isn't flammable.

My flux is a "No clean", so non-corrosive and IPA does dissolve it, but, it's still sticky even after a few IPA baths and soaking up immiedately, removal by repeated dillution.  It still ends up leaving a sticky film on the PCB that then collects lint and fibres from ... everything really.

More annoying.  When you pick an old project off the shelf thats covered in dust, blowing the dust off, doesn't work.  It's glued on by the flux.

Does water soluabe flux have any disadvantages?

We use Chemtronics flux off (applied by hand) to clean some hand soldering residues from some sensitive areas. Works great. I personally don't like the smell of it.
Now after a bit of googling, they sell specific stuff for this.
https://www.eleshop.nl/pcb-schoonmaakoplossing-voor-ultrasoon-baden.html

I have to give this one a try.

[asmi]

You don't put IPA in ultrasonic cleaner as it can set your house on fire.
I haven't figured out yet what would be the optimal way of cleaning soldering flux with it yet.

I use 1:10 mix of IPA with distilled water, which means a solution with about 10% IPA.

[paulca]

Isopropanol is not that toxic, being somewhat more potent as an intoxicant than ethanol. It has been drunk by alcoholics when no other alcohol can be sourced but this is NOT a good idea. The effects of isopropanol are longer lasting than those of ethanol and it is metabolised by the liver into acetone which will be detected on one's breath.

It wouldn't mater if it was ethanol.  It's a well known activity and it holds the same risks as solvent abuse be it ethonal, iso, or glue solvents. 

When you drink it, it enters you stomach and is dilluted immediately.  It then has to take the slow journey into your intestine where it is slowly taken up into your blood.

When you inhale the rich vapours it goes straight to the blood, straight to the brain.  The "blood alcohol level" can surge RAPIDLY out of control. 

You will likely feel drunk first.  You should get a window of "I feel drunk" before you no longer give a shit.

[paulca]

With that said, I now do most of my ultrasonic cleaning with either aqueous cleaners, or with pure water for water-soluble flux. ChipQuik's water-washable no-clean flux is kind of the best of both worlds, in that it's noncorrosive, but still water soluble. Heck, you barely need ultrasonic for it, it washes off readily in hot water!

I think the specific PCB cleaner stuff might be my best bet.  Stuff sold for removing flux that isn't flammable.

My flux is a "No clean", so non-corrosive and IPA does dissolve it, but, it's still sticky even after a few IPA baths and soaking up immiedately, removal by repeated dillution.  It still ends up leaving a sticky film on the PCB that then collects lint and fibres from ... everything really.

More annoying.  When you pick an old project off the shelf thats covered in dust, blowing the dust off, doesn't work.  It's glued on by the flux.

Does water soluabe flux have any disadvantages?

We use Chemtronics flux off (applied by hand) to clean some hand soldering residues from some sensitive areas. Works great. I personally don't like the smell of it.
Now after a bit of googling, they sell specific stuff for this.
https://www.eleshop.nl/pcb-schoonmaakoplossing-voor-ultrasoon-baden.html

I have to give this one a try.

"schoonmaakoplossing" ya gotta love german.

[Zucca]

"schoonmaakoplossing" ya gotta love german. Dutch?

FFY

[David Hess]

I add a little bit of dish soap.

When you pull the board out of the bath, rinse it down with pure solvent using a squirt bottle and let it drip back into the tank.  An air compressor is good for getting solvent out from under parts.  Use an oil-less compressor to avoid contamination.

I have thought about getting a food dehydrator to bake out boards.  I suspect it will work better than a kitchen oven.

[Someone]

I add a little bit of dish soap.

I had a chemist go through some commercial non flammable board cleaning products, they said most were basically the same as dish liquid concentrate. But cheaper!

Either way, gloves and eyeglasses needed.

[Sorama]

With that said, I now do most of my ultrasonic cleaning with either aqueous cleaners, or with pure water for water-soluble flux. ChipQuik's water-washable no-clean flux is kind of the best of both worlds, in that it's noncorrosive, but still water soluble. Heck, you barely need ultrasonic for it, it washes off readily in hot water!

I think the specific PCB cleaner stuff might be my best bet.  Stuff sold for removing flux that isn't flammable.

My flux is a "No clean", so non-corrosive and IPA does dissolve it, but, it's still sticky even after a few IPA baths and soaking up immiedately, removal by repeated dillution.  It still ends up leaving a sticky film on the PCB that then collects lint and fibres from ... everything really.

More annoying.  When you pick an old project off the shelf thats covered in dust, blowing the dust off, doesn't work.  It's glued on by the flux.

Does water soluabe flux have any disadvantages?

We use Chemtronics flux off (applied by hand) to clean some hand soldering residues from some sensitive areas. Works great. I personally don't like the smell of it.
Now after a bit of googling, they sell specific stuff for this.
https://www.eleshop.nl/pcb-schoonmaakoplossing-voor-ultrasoon-baden.html

I have to give this one a try.

"schoonmaakoplossing" ya gotta love german.

German??
You mean Dutch?

[tooki]

With that said, I now do most of my ultrasonic cleaning with either aqueous cleaners, or with pure water for water-soluble flux. ChipQuik's water-washable no-clean flux is kind of the best of both worlds, in that it's noncorrosive, but still water soluble. Heck, you barely need ultrasonic for it, it washes off readily in hot water!

I think the specific PCB cleaner stuff might be my best bet.  Stuff sold for removing flux that isn't flammable.

My flux is a "No clean", so non-corrosive and IPA does dissolve it, but, it's still sticky even after a few IPA baths and soaking up immiedately, removal by repeated dillution.  It still ends up leaving a sticky film on the PCB that then collects lint and fibres from ... everything really.

So cleaning was very incomplete, then. Ultrasonic should help, indeed, but proper rinsing is still inescapable.

Does water soluabe flux have any disadvantages?

Normal water-soluble flux (i.e. the ones that are not explicitly labeled as "no-clean water-washable") is corrosive, both before and after soldering. For those, flawless cleaning is an absolute must. (The residues can be hygroscopic, too, also encouraging corrosion.) But the advantage is that cleaning is very easy, since they dissolve readily in water.

Most importantly, such flux must never be used for joints that cannot be cleaned, like when components are used that can't be washed (like many sensors and switches) or where flux wicks up into uncleanable areas, most notably in stranded wire.



No-clean water-washable fluxes, like ChipQuik's 4300 series, are essentially normal no-clean flux, but with saponifying cleaner built into the flux. They say cleaning is optional, but I do wonder if the cleaning agent could (in the long term) make it hygroscopic, or what happens if condensation occurs on a board in high humidity.

However, I will add my normal no-clean caveat: no-clean fluxes are only "no-clean" if the flux has been FULLY heated. That is guaranteed in the case of the flux core of solder wire, and when doing whole-board reflow in an oven or vapor-phase reflow device. It is NOT guaranteed when using extra flux in hand-soldering or rework, where excess flux invariably flows places you don't want, and which do not get heated completely. Such flux may be left in an active (corrosive!) state. So whenever using external no-clean flux (paste, liquid, etc) for hand-soldering or rework, consider it as "cleaning mandatory".

ChipQuik's 4300 series is very easy to clean -- it dissolves readily in hot tap water -- and that has proven to be a nice advantage. It comes off much faster than a regular no-clean in solvent or saponifying cleaner.

[paulca]

So I have had a few PCBs to clean, several times after reworks.

If I put a sticky snotty covered in flux board in with just 10% IPA at ~50C  for 15 minutes it would clean everything but the thick deposits where you flooded flood.  If I gave the board an alcohol bath and a scrub with the toothbrush first it seemed to help.  Repeatedly removing the PCB and rinsing in neat IPA before returning also seemed to improve things.

But I ordered powered PCB cleaner from a UK company, gave it a go tonight.  Made no attempt to pre-clean the board with IPA, just chucked it in for 20mins on ~50C.

Much cleaner.  Little to no sign of flux.  However, it did leave a residue.  I expect this is my error and I skipped a good water rinse to remove the detergents.  I just poured IPA over it, dabbed it dry, repeated and then put it in the oven at 60C for 10 minutes.  Next time I will add a water rinse under the tap to clear remaining detergent.

What do you think?  More wash?  Better rinse?  Prewash neat IPA?

[SteveThackery]

Does anyone have an opinion on the optimum "watts per litre"?

I've had a few ultrasonic cleaners in the past, and the cheaper ones are sometimes too gutless to work well. I suspect the "ultrasonic power" claims of certain cheap Chinese ones might be grossly exaggerated.

[paulca]

Does anyone have an opinion on the optimum "watts per litre"?

I've had a few ultrasonic cleaners in the past, and the cheaper ones are sometimes too gutless to work well. I suspect the "ultrasonic power" claims of certain cheap Chinese ones might be grossly exaggerated.

I assumed the power figure was the heater.

[SteveThackery]

Does anyone have an opinion on the optimum "watts per litre"?

I've had a few ultrasonic cleaners in the past, and the cheaper ones are sometimes too gutless to work well. I suspect the "ultrasonic power" claims of certain cheap Chinese ones might be grossly exaggerated.

I assumed the power figure was the heater.

Cleaners with heaters (ie all but the smallest ones) usually quote two separate figures. The ultrasonic power is by far the most important one.

[asmi]

Another interesting side effect of ultrasonic cleaning is that it forces bad solder joints to fail, so after a wash you need to do an inspection to check for any missing parts (or to check a tank for presence of any components which should not be there). This is of course a net positive as otherwise these parts would've likely failed during shipping, or in the customer's hands, which would've made a fix significantly more expensive because now you need to do an RMA on top of a fix, and also potentially deal with the reputational damage if this becomes public.

But beware that some parts will not survive ultrasonic cleaning. These are usually components which have some sort of open cavity that is required for it's proper operation - like a small hole in atmospheric sensors like BME2xx/BME3xx which needs to stay open for sensor to actually work, or SMD MEMS microphones - for the same reason.

[tooki]

So I have had a few PCBs to clean, several times after reworks.

If I put a sticky snotty covered in flux board in with just 10% IPA at ~50C  for 15 minutes it would clean everything but the thick deposits where you flooded flood.  If I gave the board an alcohol bath and a scrub with the toothbrush first it seemed to help.  Repeatedly removing the PCB and rinsing in neat IPA before returning also seemed to improve things.

But I ordered powered PCB cleaner from a UK company, gave it a go tonight.  Made no attempt to pre-clean the board with IPA, just chucked it in for 20mins on ~50C.

Much cleaner.  Little to no sign of flux.  However, it did leave a residue.  I expect this is my error and I skipped a good water rinse to remove the detergents.  I just poured IPA over it, dabbed it dry, repeated and then put it in the oven at 60C for 10 minutes.  Next time I will add a water rinse under the tap to clear remaining detergent.

What do you think?  More wash?  Better rinse?  Prewash neat IPA?

Do you still not understand that solvents and detergents do not destroy flux, they only dissolve it? What ever gave you the idea that you did not need to thoroughly rinse with clean water or solvent after washing? Haven’t you ever watched a clothes washer or dishwasher? They have a wash cycle and usually multiple rinse cycles.

After washing with the PCB cleaner you bought (which I assume is aqueous (water-based) since you said it was powdered (right?)), you need to rinse thoroughly with lots of tap water, then quickly shake, blot, or blow off as much of the tap water as possible and immediately give a final rinse with either distilled/deionized water or very pure solvent. (Tap water contains minerals that can be conductive and later on lead to electrolytic corrosion, so it must not be used for the final rinse.) Shake, blot, or blow off the final rinse. (I prefer using compressed air.) It’s usually not necessary to dry in an oven.