Ultrasonic cleaner size: 10L vs 6L

[coppercone2]

I think bigger is better with more isotropic behavior without fringe focusing effect from edge reflection (rounded edges parabola like) that can lead to spot damage

[tooki]

I’ve seen Rolex watches in shop windows though!

I think Rolex are seriously over-rated.  People in the know buy Zenith. 

Like the old TVs?

Just kidding. But I honestly know nothing about watches beyond a few brands I’ve heard of. (Omega, Tissot, Jaeger, and Rolex come to mind.) As impressive as I consider the micro-machining required to make them, I have no use for the product!

[jpanhalt]

I use non-aqueous fluid for small steel components like watch parts, in order to avoid any risk of rusting.

Jewelers in America used a cyanide containing aqueous cleaner for watches and other jewelry.  An uncle was a jeweler from the early twenties for over 30 years.  In the 1950's, he  was till using the same type of solution.  After agitation in the sodium/potassium cyanide solution (probably some other stuff was there too), the basket of parts was rinsed and dried in fine sawdust.  He told me a story that when the stock market crashed, some heavily leveraged jewelers drank the solution to commit suicide.  That was his way to warn me it was dangerous if not used properly.  Apparently, that solution was still available and used  in the 21st century: https://www.researchgate.net/publication/281743306_Acute_Cyanide_Poisoning_from_Jewelry_Cleaning_Solutions

There are some steel parts in watches, such as stems and mainsprings, but using that wash did not cause rusting.  The advantage of aqueous solutions is they are far better than any non-aqueous solution at removing inorganic salts, dirt, dust, etc., and rinse solutions are as cheap as water.

EDIT: I am not recommending that solution of ultrasonic cleaning.  The degassing effect could increase the danger a lot.

[mendip_discovery]

I had the transducers on mine fall apart. I fitted new ones using arledite to glue them on. Works great now. I use it for cleaning motorcycle parts, mostly carburettor and stuff.

Go big or go home. You will find it easier to use than a small one.

I never worried about the bubbles as I thought that was part of the idea of these cleaners as the cavitation is what is doing the cleaning. Then again I don't put boards in mine.

[coppercone2]

I really think people need to look into electro cleaning. It takes some research but brush and dip electrocleaning are powerful techniques that don't require anything too dangerous (just wear goggles).

I electro cleaned my HP RF impedance analyzer test fixture gold parts and they came out looking better, the solution got a little dirty and it took me only a minute with house hold chemicals and the lowest power and cheapest DC power supply

I am telling you these methods are powerful, it just requires some things that most people find way too hard (alligator clips and getting the polarity right).

I think its because people think that its way more sensitive to the options that you have like partial AC, Pulse, frequency, etc. Really, the parts are not going to get easily messed up

Same for the weld cleaning industry, they made up a paper tiger out of all the god damn options that you have. What current, if its AC or DC or what brush... jesus.. it might have a bit of use if you wanna get the settings right for the first time for grumpy ass welders that refuse to put down the grinder... but its like the most insensitive god damn thing there is. You tune it with a current knob while your working to get the correct results like finding a radio station... but if you read the literature they make you feel like your part is gonna fucking disintegrate if you get it wrong LOL. I think alot of people shy away from the process because they have some ridiculous idea about how it actually ends up working in practice. The reality is kind of like deciding how hard you need to rub a brillo pad. The impression from literature is that its working with a overloaded Romulan Disruptor.

[SteveThackery]

I never worried about the bubbles as I thought that was part of the idea of these cleaners as the cavitation is what is doing the cleaning. Then again I don't put boards in mine.

It is the cavitation, but not of those visible bubbles.  The bubbles that do the cleaning are microscopic.

I've just checked my supplier: most watch cleaning solutions are waterless, but there are a few that come as a concentrate which you dilute with water. They claim to have an anti-rusting additive.

[watchmaker]

I agree with the electro cleaning, although I use ultrasonics.  The reason watchmakers use ultrasonic is because of the requirements for getting a parts account.  But every jeweler is familiar with elector cleaning.

The disadvantage of ultrasonic is its very reason for use; cavitation.  I have seen the plating of Omega mvts removed and the bimetallic balances of high grade vintage watches destroyed by either too much power (this was adjustable on older machines) or being left in too long.  The brass on the balance becomes very friable and it's action is destroyed.

As for Rolex vs Omega, this is a religious argument.  And we all know how well that worked in Switz before the Federation.

[SteveThackery]

Thanks for that information, Dewey.

There is something I don't understand. How can electrocleaning remove contaminants such as grease and oil from a surface? These are waterproof and non-conductive, so I don't understand how current can flow to or from such surfaces.

https://www.sharrettsplating.com/blog/what-is-electrocleaning/

This webpage seems like a good overview of the subject, but it says that the bubbles are formed "under" the contaminants, but that doesn't make sense to me for the reason given.

[SteveThackery]

The brass on the balance becomes very friable and it's action is destroyed.

It's also worth pointing out that ammoniated cleaners are popular for (especially) clock repairs, but prolonged immersion of brass in ammonia destroys its integrity.  I've read that it dissolves the zinc from the brass, but I don't know if that bit is true or not.

[coppercone2]

Thanks for that information, Dewey.

There is something I don't understand. How can electrocleaning remove contaminants such as grease and oil from a surface? These are waterproof and non-conductive, so I don't understand how current can flow to or from such surfaces.

https://www.sharrettsplating.com/blog/what-is-electrocleaning/

This webpage seems like a good overview of the subject, but it says that the bubbles are formed "under" the contaminants, but that doesn't make sense to me for the reason given.

well its not quite that simple. You require a degreasing step, and the most common electrocleaners use a base, or mixture of bases. TSP, hydroxides, carbonates, which will dissolve grease.

I don't think it will get something like a drop of tar off your cleaning work. I thinks its more along the lines of at the exposed area, super active 'stuff' is formed by electricity, and the bubble, that kind of undermines and pulls the grease adjacent to the clean spot off.


And if you ever play with paint stripper you will notice what it does to grease or paint. It swells up and wrinkles and seems to absorb the chemicals. I would not be suprised if the thinner areas of grease turned into electrically conductive 'gels' after being exposed to the solution. This effect is present, but you need much less concentration of it for electrolytic cleaning to start doing work for you. If you wanna just scrub it off, you pretty much need severely caustic mixtures (i.e. 50% NaOH)

It does not just uniformly dissolve, you start seeing like... crap being lifted from the surface and floating around (big "chunks" that can be filtered out of the solution later). To me, this implies that the electrocleaning is disturbing a base level bond near the surface of the metal with the contaminant. It very much reminds me of what happens to a frying pan thats caked and soaking in soap for a day after you first start to agitate it with a brush, but without the brush.

The only thing I don't like is the smell of it. Its very faint but I just find it very disagreeable.

[SteveThackery]

Go big or go home. You will find it easier to use than a small one.

Except in this case the bigger cleaner has a lower power-per-litre than the 6L one. I do agree that a larger tank is more useful though.

[watchmaker]

The brass on the balance becomes very friable and it's action is destroyed.

It's also worth pointing out that ammoniated cleaners are popular for (especially) clock repairs, but prolonged immersion of brass in ammonia destroys its integrity.  I've read that it dissolves the zinc from the brass, but I don't know if that bit is true or not.

Steve,

Two things about ammonia in cleaning solutions.  It is waste. Excess ammonia means the proportions for making the soap are wrong.  How do I know?  I hold the tradmark to "Historic TImekeepers Ultrasonic Cleaner" as sold by Timesavers and others for two decades.  It was a low ammonia alternative to L&R which forced them to reformulate.

Secondly, ammonia only degrades items like stamped brass.  It was uncovered as a result of brass cartridge failures in the imperial UK army.  The myth about it attacking brass clock parts was created by a guy back in the days of the Syracuse Clocks listserv (1994 to about 2002).  This guy said he had thousands of photomicrographs of SCC failures but when we started calculating man hours and dollars, we pinned him down and he had to admit it was all a thought experiment a al "Sir"Cyril Burt (nature vs nurture twin studies).

But when a lie is repeated often enough....

Look up research on Stress Corrosion Cracking.  Last I looked it all involved drawn or stamped brass in high pressure ammonia environments.

It is really like "personal magnetism" used to explain why a watch performs poorly.

Cavitation is the concern for timepieces.  In fact,for ancient items, I will use ivory soap in very hot water lathered up on a very soft brass bristle brush (feels like a dust brush almost). With this, I can remove fingerprint stains on chronometer plates without harming the spotting (decoration).  But if the prints are acid etched into the brass, that remains.

Gold gilding comes up like new.

[SteveThackery]

Thanks, Dewey, that's all really interesting.

One of my British Horological Institute tutors said the same thing about the types of brass affected by ammonia. I have actually damaged one clock part in this way - I accidentally left it immersed in ammoniated clock cleaner for three whole days. The result was to give it a fine frosted look rather than its original shine. I don't know if there were any structural effects - no way of knowing.

As a rule I use aqueous ammoniated L&R on clocks; on watches I use petroleum ether followed by isopropanol - the two different solvents seem to clean up the old lube pretty well. Let me know if you think this is the wrong approach. 

[jpanhalt]

As a rule I use aqueous ammoniated L&R on clocks; on watches I use petroleum ether followed by isopropanol - the two different solvents seem to clean up the old lube pretty well. Let me know if you think this is the wrong approach. 

I don't do clocks or watches anymore, but I still enjoy working with mechanical parts.  To me, petroleum ether means short chain, non-aromatic hydrocarbons, like hexane.  It is hard to get in the US.  Mineral spirits/paint thinner is similar but much higher boiling.  I use VM&P Naphtha, which is widely available, for fine cleaning in the house and Stoddard or similar for heavy grease in the barn shop (e.g., my parts washer).*   I like them as the increased aromatic content helps with grease and sticky labels.  I sometime wash with an alcohol, acetone, or MEK.   

I came across a reference that may help clear up all of the confusion about names for hydrocarbon solvents: https://cool.culturalheritage.org/waac/wn/wn29/wn29-2/wn29-204.pdf

John

*"Parts Washer" labeled solvents are expensive near me.  That is, compared to the days when when you could go to a a local Mobile station and pump it like gasoline.  Fortunately, there's a well  known dragstrip nearby (Norwalk Speedway).  It's supplier is quite cheap and is willing to sell to me in 5 to 10 gallon amounts.  It is basically Stoddard.   

[coppercone2]

oh no not hexane petroleum ether is a very low boiling point solvent designed to boil at the same point as diethyl ether when colliqually refereed to in the USA by most places. It plumes. hexane is a good 30 degrees higher boiling point. I think mine was 30-35C boiling point from Sigma.

Petroleum ether is not known to be nearly as toxic as hexane. Some people might call it zippo fluid, but its available in very high purity as a lab reagent. Hexane has a bad rep. Heptane has a better reputation. Petroleum ether has a much lower point then benzene, which is the most harmful organic solvent in common use, so its safer in that regard since if it won't have benzene in it because of a very big boiling point difference.

The benefit over ether is that it does not absorb water, so it can be stored easier( PE is very non polar). ethyl ether is probobly biologically safer, but possibly more explosive and has strict storage requirements with moisture absorbers and also stabilizers to prevent peroxides from forming (which can explode), but its usually not a problem for cleaning, more like if you distill a bunch of ether out of something and are left with a big glob of ether peroxides in a flask for organic extractions.



Keep in mind though, plumey solvents can accumulate vapors in low spots. You gotta be well ventilated to work with that in large quantities. You could end up with a plume of vapor on the floor that can ignite easily because of its low flash point... i.e. a switch clicking on in a fridge.


Its hard to work with if you wanna wipe something down because it really evaporates fast


This is what I would expect in a USA lab
https://lab.honeywell.com/shop/petroleum-ether-77399

[jpanhalt]

I don't know what your link is selling at that outrageous price.  What we called petroleum ether light boils at 60° to 70°C.  Hexane boils at the higher end of that range; however, it is a mixture.  When I was in school, we did not have UV grade hexane.  We started with technical grade 60-70 and purified it to get a UV cutoff of about 220 nm, which was sufficient for our needs.  Its volatility is hardly like diethyl ether (or methylene chloride).   

[coppercone2]

I don;'t see the point of calling it ether, its usually used when you would wanna use ether for its volatile properties but without moisture restrictions without going to butane

I would call that naphta. The beauty of the PE is that it evaporates your sample really quick (i.e. dirt oil extraction for testing for pollutants), which is very useful for a analytical lab that is tasked with testing a sample. It is extremely non polar.

If it has a high BP then its not very ether like 


Often used if you find oil on dirt and it needs to be tested for environmental reasons.

That one i linked is 30-40C, ethyl ether is 35c, its real close, the lab procedures behave largely the same for extractions with greater safety margin and no moisture controls!

And since the boiling point is so low, you know your not adding anything that will be hard to extract from your extracted oil before it gets tested for say PCB or other additives. A higher BP thing might linger in the tiny amount of oil you extracted then be a pain to remove later without disturbing the mixture thermally. Butane would work here too but its hard to work with for normal lab people, but if you had a special contained machine it would be better probobly.

[SteveThackery]

I bought my most recent petroleum ether from eBay, and the supplier offered it with a range of different boiling points.

I found that the lower boiling point products were not obviously any more effective as a solvent for solidified old oil than the higher boiling point versions, so I now use one rated at 100 - 120 Celsius boiling point.

The BP ranges are: 40 - 60, 60 - 80, 80 - 100 and 100 - 120 Celsius.

[jpanhalt]

100° to 120°C is the octanes range.  I utilized isooctane (bp 99°) for a tricky crystallization of an unexpected aromatic hydrocarbon (identified as tetrabenzanthracene, C30H18) from benzene.  That was in a former life.  I like the sweet smell of isooctane.  Your pet ether probably doesn't smell so good. 

Are we far enough OT yet?

[coppercone2]

the other benefits of the PE is that its a mixture of various things, usually solvent mixtures work better for unknown samples because you never know what has the best solubility, regardless of the BP range, you get a bundle of solvents

[SolderOcelot]

Well after progressing to a second page on this thread I still don't know if I should swap my 10L ultrasonic cleaner for the 6L but I have now acquired a bachelor degree in chemistry having read all these comments.

[jpanhalt]

I have 2 straightforward questions:
1) Do you think the 6L basket size is enough for most laptop motherboards?
2) Is it true that less runtime is needed for the smaller tank and thus is safer for laptop motherboards (or any other populated pcb for that matter?

My reading of the first page was that almost everyone recommends the larger unit.  For me, any advantage of the 6L would be offset by the fact you already have a 10L version.  As an aside, after a page of any thread, posts tend to wander.

Power density has been addressed.  You can increase time, if necessary, but you can't increase size or easily throttle power. 

The thread then wandered into whether your diluted IPA was the appropriate cleaner.  Water alone is sometimes called a miracle solvent.  Over time, it can dissolve solid rock and build mountains. In human terms @tooki and others suggested better cleaners depending on what you want to remove.  The frequently observed "white residue" probably requires a saponifier (alkaline) remover in water.  IPA and absolute ethanol (my personal favorite) are not very effective.

Edit: BTW, you are probably referring to a BS in chemistry, not BA/AB degree. 

[SolderOcelot]

Power density has been addressed.  You can increase time, if necessary, but you can't increase size or easily throttle power. 

You could not have worded that in a more powerful and convincing way. Almost poetic. You can increase time, but you can't increase size

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.

[jpanhalt]

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.

Not Ivory dish soap (https://en.wikipedia.org/wiki/Ivory_(soap)#:~:text=The%20soap%20has%20a%20determined%20pH%20value%20of%209.5.&text=Ivory%20dishwashing%20liquid%20contains%20water,detergent%20instead%20of%20a%20soap ).  As pointed out (@tooki), it's a soap not a saponifier.  Ivory dish detergent (loc. cit.) is different. 

It is said that Tektronix used to use an ordinary household dishwasher to clean boards sent for repair. I am not sure what it used for detergent. Dishwasher detergents are far more caustic/alkaline than Ivory soap is. This article from Kester discusses its investigation into the "white residue:"  https://www.kester.com/Portals/0/Documents/FAQs/White_Residue.pdf

It convinced me.  I had found empirically that cleaning a DIY board right away with absolute ethanol was never a problem.  Cleaning a SparkFun solderable breadboard immediately was rarely a problem, but after awhile, one would get white residue.  I did a project with a commercially made PCB that had a TQFP chip and was done with reflow (Kester leaded solder).  White residue was a problem even when cleaned immediately.  I tried a DIY water-based remover with ethanol amine as saponifier as described earlier, and the result was great.  That convinced me.

For cleaning dirt, dust, dead bugs, etc., almost anything in water with a little surfactant activity should work.  For flux, you need something different.

[watchmaker]

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

My favorite supplier closed out on them several years ago and I purchased what I hope is lifetime supply.

Cousins in the UK may have them.