Have a ultrasonic washer but not knowing what detergent for cleaning soot

[Grossel]

I have a (cheap but functional) ultrasonic cleaner.

And I have some items - small connectors having being close to a fire. Those connectors are heavily sooted and I'd like to know what detergent being effective on soot, but also without making any damage to plastic, rubber or metal.

I'm located in Scandinavia, Europe so any product being suggested must also be possible to purchase from Amazon (ebay have some hefty shipping fee for items located in usa, often much more expensive than the product itself).

 

[rjenkinsgb]

Try general purpose household cleaner / floor cleaner, in a fairly strong mix with water?

I use that (liquid flash or ajax) for such as watchstraps and jewellery etc., it is very effective.
Rinse thoroughly in clean water and give a couple of extra rinses in the ultrasonic.

For electronics, do the final rinse in the ultrasonic using deionised water & dry with warm air.

 

[jpanhalt]

I agree in part with "floor cleaner." You have to read the label. Some will be based on ionic detergents, which might leave residues or bound ionic compounds.

I switched to ZEP heavy duty floor stripper for removing flux from whole boards several years ago. It will dissolve acrylic floor wax and even softens cured enamel at higher concentrations. It's main ingredient is butyl Cellosolve (2-butoxy ethanol), which is a great solvent with a distinctive smell and is non-ionic. It's in many such cleaners. Cellosolves are a class of solvents with both a hydroxyl (from ethanol) and ether function (from butoxy). They were invented in the early 20th century, and as a class are great solvents. Most also contain ethanol amine to make them alkaline. That satisfies the need for a saponifier to remove most fluxes.

For removing flux you need about 10% butyl Cellosolve in the final dilution. That's about 1 part of floor stripper to 3 or 4 parts total volume with water. Kesters water-based flux remover, which has the same formulation, starts with a higher concentration of the Cellosolve and is used at about a 1:10 dilution. It needs to be rinsed, and I recommend deionized or distilled water for a rinse.

For removing smoke, you can probably get by with a higher dilution (e.g., 1 part to 10 total). I don't do much restoration and have not tried it. You can probably just follow the label for cleaning, not stripping.

One advantage of ZEP over Kesters is that it's usually available locally and cheap (about $14/gallon in the US). Years ago, I was told it is available in most countries, except Australia. I have not checked since. If you can't get ZEP, its formulation is not unique, and there are probably good substitutes. One thing I would avoid are cleaners with fragrances to give a "clean smell" -- whatever that means.

 

[Grossel]

Thank you guys for most helpful answers.

I found this zepeurope.com web site, so greater chances to get a appropriate product.

[edit]
I filled out the form on the web site mentioned above and asked if ZEP heavy duty floor stripper is possible to purchase from my location (I find the product on Amazon, but doesn't offer shipping).

[edit 2]
I've also asked for this in a local web forum, and got a recommendation for Simple Green all-purpose cleaner. How do you think this product compares to the ZEP heavy duty floor stripper for the purpose of mine?

 

[rjenkinsgb]

Simple green is apparently very good, though very expensive (at least in the UK).

Another good cleaner I use lot of - "Dettox" or the supermarket own brand versions; clear general purpose no-rinse kitchen surface cleaner. It's pretty much the same as industrial grade cleaning sprays, even good for machine operator panels etc. in engineering companies.

 

[ZipZapOuch]

Do not use solvents (butyl cellusolve) in a sonic bath. These are not "EP-rated" devices which means they likely create sparks when you flip the switch or when the relay engages.

Sonic baths move molecules very fast and can rapidly increase the concentration of the vapor in the air near the bath as the micro droplets emitted from the surface evaporate into the air. A nearby spark can create a vapor cloud explosion or vapor cloud flash (and you can have even more soot.

Before going with solvents, try a low-foaming detergent as used in a front-loading laundry washing machine. More detergent isn't better. Use about a tablespoon per liter of sonic bath water.

Rinse well but there should be little residue that would cause problems. Most modern detergents (e.g. Percil) are non-ionic surfactant polymers with a very soluble hydrophillic end and a poorly soluble hydrophobic end. No electrically conductive or corrosive ions.

 

[ZipZapOuch]

Do not use solvents (butyl cellusolve) in a sonic bath. These are not "EP-rated" devices which means they likely create sparks when you flip the switch or when the relay engages.

Sonic baths move molecules very fast and can rapidly increase the concentration of the vapor in the air near the bath as the micro droplets emitted from the surface evaporate into the air. A nearby spark can create a vapor cloud explosion or vapor cloud flash (and you can have even more soot.

Unfortunately, this is a minor concern. The major concern is that butyl cellusolve swells, softens, embrittles many polymers. The swelling can cause micro cracking as the solvent SLOWLY migrates out of the plastic, rubber or elastomer. As mentioned, it dissolves acrylic, enamel and more. I'm not sure what it will do with your wires or connector housings or any heat shrink tubing.

Before going with solvents, try a low-foaming detergent as used in a front-loading laundry washing machine. More detergent isn't better. Use about a tablespoon per liter of sonic bath water.

Rinse well but there should be little residue that would cause problems. Most modern detergents (e.g. percil) are non-ionic surfactant polymers with a very soluble hydrophillic end and a poorly soluble end.

 

[jpanhalt]

Do not use solvents (butyl cellusolve) in a sonic bath. These are not "EP-rated" devices which means they likely create sparks when you flip the switch or when the relay engages.

BS. I don't care about EP rating. And besides Dettox does not even have an MSDS I can find. Google converts it to Dettol, which contains:

As for effects on plastics the behavior of pure butyl cellosolve are irrelevant to dilutions in water with 10% or less. Neat, it will remove cured enamel as mentioned. You simply cannot ignore the effects of water on solvents that are miscible in it. Ethanol being another example. The difference between 100% (absolute) and 95%(its azeotrope) are striking.

 

[Grossel]

A little side step - but EP ratings as I understand it just tells if some mixture are less dangerous for humans ?

 

[ZipZapOuch]

A little side step - but EP ratings as I understand it just tells if some mixture are less dangerous for humans ?

No, sorry, it was a typo - it should have read XP ratings. Explosion proof ratings. The sparks made by the switch or relay can ignite the solvent vapors.

 

[ZipZapOuch]

The difference between 100% (absolute) and 95%(its azeotrope) are striking.

But still flammable down to 50%. And lower concentrations are still flammable as the mix is heated.

Finally, the sonic action creates cavitation in the mixture. The cavitation is typically water vapor but, when molecules with a higher vapor pressure are present, those will preferentially form the vapor to fill the cavity - just as they would boil off first during a distillation.

So, no BS.

 

[jpanhalt]

ZipZapOuch
Do you know what "flash point" means? The flash point of 2-butoxyethanol is 67°C (153°F) neat. Most people will not be heating their ultrasonic to anywhere near that temperature when cleaning PCBs.

I need only 1 minute to clean most boards and 1.5 to 2 minutes for really stubborn residues that left lots of white precipitate between the pins of small pitch devices. They barely get warm. Highly diluted in water to which it binds that flash point for the mixture is probably higher as the sum of the two vapor pressures will be close to the atmospheric pressure at the location.

Basically, you can light your cigarette without fear. (I do not smoke, but observed another grad student showing off about the ignition temperature of diethyl ether with an already lit cigarette. It didn't end well. He had done it before, but in that case, there was a spark.)

 

[rjenkinsgb]

Sonic baths move molecules very fast and can rapidly increase the concentration of the vapor in the air near the bath as the micro droplets emitted from the surface evaporate into the air. A nearby spark can create a vapor cloud explosion or vapor cloud flash (and you can have even more soot.

Using flammable solvents in ultrasonic cleaners is quite common practice.

eg. Such as the cleaner below.
(Some people use Benzine or isopropyl alcohol rather than this or the matching L&R rinsing solvent).

 

[Grossel]

Ok, wasn't aware of flammable aspect of some detergents.

I believe that detergent as suggested by rjenkinsgb should never be used within the house, at least. I mean, I'm not the only one in the house, so safety are a great concern also.

 

[ZipZapOuch]

Ok, wasn't aware of flammable aspect of some detergents.

I believe that detergent as suggested by rjenkinsgb should never be used within the house, at least. I mean, I'm not the only one in the house, so safety are a great concern also.

I'd give the laundry detergent+water a try first. Safe for fire, safe for the plastic and cables, safe for copper/tin

 

[rjenkinsgb]

Ok, wasn't aware of flammable aspect of some detergents.

I believe that detergent as suggested by rjenkinsgb should never be used within the house, at least. I mean, I'm not the only one in the house, so safety are a great concern also.

I suggested only the stuff below, for your application. (I forgot Dettox was renamed, I think at the start of the pandemic). The L&R cleaner was just to show that flammability is not a relevant point with ultrasonic cleaners.

(I do regularly use the L&R liquids in the ultrasonic cleaner which I keep in my kitchen - the smell is not bad, nowhere near as strong as with ammonia for domestic cleaning that is still in use by some people.)

 

[crutschow]

There are soot remover products listed on Amazon, which may work well for that purpose.