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Ultrasonic cleaning

This topic has 27 replies, 16 voices, and was last updated 3 October 2016 at 10:57 by Russell Eberhardt.

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30 September 2016 at 15:47 #258603
Russell Eberhardt
Participant
@russelleberhardt48058
The recent article describing the Allendale ultrasonic cleaner gave me food for thought. I have used a little 50 W Aldi model for some time for cleaning my wife's jewellery and have not been very impressed.

I ended up buying a 120 W 3 litre model from Ebay for just under €80 delivered from here

My first test was to clean a couple of watches with expanding stainless steel straps. For the cleaning fluid I just filled the tank with de-ionised water and added 20 ml of general purpose detergent and 10 ml of household ammonia solution. Both watches had been recently cleaned in the Aldi unit and I was horrified to see how black the cleaning fluid became! Obviously the Aldi unit wasn't working very well. A few odd parts with engrained grease were tried after removing the worst with a solvent and came up very nicely.

I have ordered some citric acid to make up a rust removing solution and hope that the results are as good. There are loads of recipes online for suitable cleaning fluids but they don't seem to be critical and making them up is much cheaper than having the supplies shipped from the UK.

Any one else have any good tips?

Russell.
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30 September 2016 at 15:47 #38372
Russell Eberhardt
Participant
@russelleberhardt48058
30 September 2016 at 16:33 #258607
Martin King 2
Participant
@martinking2
Hi Russell.

I have a 6 litre heated unit from Allendale and use it on an almost daily basis for old lathe parts and anything that is greasy and dirty prior to refinishing.

I use water and a large dash of Fairy liquid. Results are excellent, particularly for getting old paint off, couple of hours on hot and it just scrapes off easily.

Periodically i empty out the 2" of crud in the bottom, wipe out with kitchen roll and run round the tank with a cloth soaked in acetone, comes up like new! Get the basket, really usefull. For small parts I use one of those tiny tea ketle like tea holders and just chuck it in.

If I need to use another solvent I put the in a jam jar with the parts and drop the jar in the water, has the same cleaning effect.

Great bit of kit, I am thinking of getting a bigger size one soon.

Cheers,

Martin
30 September 2016 at 16:45 #258610
Neil Wyatt
Moderator
@neilwyatt
I must admit, I really was taken aback by just how well the Allendale tank cleaned up the castings. the photos really don't do justice to how well it worked.

Neil
1 October 2016 at 09:22 #258689
Robbo
Participant
@robbo
I have used a 2.5 litre heated model from Allendale for a long while, and it gets used every time parts are removed from machines.

Good for removing that awful grease that the Chinese smear on all their tooling.
1 October 2016 at 10:23 #258694
Clive Hartland
Participant
@clivehartland94829
A very good aqueous solution is, 'Micro 90'. Using only a 2% solution it is quite economical. A free 8oz sample can be obtained from the supplier. tel. 0500 345 300. I have used it for many years in an industrial situation and recommend it.

Check the internet for micro 90 to see it in action.

Clive
1 October 2016 at 12:23 #258705
David Colwill
Participant
@davidcolwill19261
These are worth looking at if you want something good.

**LINK**

Notice the power input on the quality ones is much higher. The 3 litre Sonorex is listed as 480 watts of ultrasonic power. This is more than some of the 25 litre tanks on ebay so be careful when choosing one.

Frequency also plays a part. The lower the frequency the more aggressive the cleaning 40 Khz seems to be good for general purpose.

One tip as regards cleaning fluid is to us a smaller glass container with the correct fluid in it placed in the main tank filled with plain water. This saves filling the whole tank with expensive fluid.

Also you can test the action of the ultrasonic by using strips of kitchen foil placed at different locations in the tank. The foil should show holes and pitting after 30 seconds or so. All strips should show equal damage.

Regards.

David.
1 October 2016 at 12:57 #258707
Ed Duffner
Participant
@edduffner79357
Is it possible to make an ultrasonic cleaner?

Ed.
1 October 2016 at 13:07 #258708
Russ B
Participant
@russb
David Colwill, and Russell

I have a "cheap" aldi/lidl cleaner (I don't remember which one it came from)

If I put tin foil in there, they'd whizz all over the place – it gets quite a buzz going in there, even larger heavier items like keys will buzz and move slightly. I can see bubbles hovering in there too where the water is presumably shearing from the internal forces.

I use (very) hot tap water with a dash of fairy liquid – I've had very good results.

Russell, is your cheap Aldi unit as noiticeably active as this – I'm wondering if yours is a bit of a dud, or if I could achieve even better results with a proper unit.

Regards,

Russ
1 October 2016 at 13:56 #258715
V8Eng
Participant
@v8eng
Posted by Ed Duffner on 01/10/2016 12:57:24:

Is it possible to make an ultrasonic cleaner?

Ed.

Well the Transducers and boards are quite readily available, I suspect that producing a successful machine might be more involved than initial impressions would indicate.

The other critical factor might be the overall build costs relative to buying a ready made unit.

I have a small Aldi (I think) Ultrasonic Cleaner, it seems to work well for Jewellery etc.

Edited By V8Eng on 01/10/2016 14:02:54
1 October 2016 at 14:19 #258718
Phil P
Participant
@philp
I work for a company that manufactures ultrasonic cleaning tanks ranging in size from 1 litre to around 500 litres.

The problem you will have is the bonding of the tranducers onto a tank, it is the most critical process in the whole build and uses special adhesives that are oven cured, so I would say to you "don't try this at home"

Phil
1 October 2016 at 17:41 #258741
Enough!
Participant
@enough
Posted by Ed Duffner on 01/10/2016 12:57:24:

Is it possible to make an ultrasonic cleaner?

Sure – the manufacturers do it the time

Back in the day, Heathkit had a kit for one. I still have mine. They ran into some trouble in Canada (or perhaps North America) with the insulation provided by a power transistor washer and issued an update kit consisting of a beryllium washer replacement (which thought was pushing it a bit).
1 October 2016 at 19:05 #258747
Michael Cox 1
Participant
@michaelcox1
Many years ago I bought an ultrasonic fog maker in Maplins. At the time I think I paid around £10 for it. They no longer seem to stock this type of equipment but they are still available on ebay. Here is one example priced at £3.99:

http://www.ebay.co.uk/itm/Ultrasonic-Mist-Maker-EU-Plug-Fogger-Water-Fountain-Atomizer-Air-Humidifier-24V-/322118701179?hash=item4affc5507b:g:ljYAAOSwNsdXQsyT

I have used mine on many occasions to clean my wife's jewelry. I just put the fogger in a deep contained with the jewelry and then fill with water containing some detergent. It is amazing how much muck comes out of an expanding metal watch bracelet.

It could be useful for cleaning small parts. I am not sure how resistant it would be to non aqueous solution such as kerosine.

Mike
1 October 2016 at 21:14 #258765
V8Eng
Participant
@v8eng
I think the Maplin type of units are used to make steam effect systems for electrically powered steam locos.

We used to use ultrasonic mist generation units mounted in the AHU as part of the humidity systems in close control environment rooms.

Edited By V8Eng on 01/10/2016 21:16:13

Edited By V8Eng on 01/10/2016 21:22:27
1 October 2016 at 21:30 #258767
Bikepete
Participant
@bikepete
This thread reminded me to dig out an ebay purchase from some time ago, a Walker Ultrasonics unit (110W, about 2 litres I think) which the seller said came out of a dentist's surgery. It had been in a cupboard for a while as I wasn't that impressed when I first got it but never got round to digging into it.

Just tried it again with some hot tap water and washing up liquid. It buzzes away all right but there's little evidence of cleaning beyond what hot water and soap would do anyway. Tried some kitchen foil and it was unaffected after 10 minutes…

Took the bottom off it for a look and the transducer is still stuck to the bottom of the tank. Could that joint nonetheless have failed, explaining the buzz yet lack of cleaning? Or were dental units like this always designed to be rather more gentle than we need for cleaning bits of metal?

Grateful for any ideas to fix/otherwise make it more effective…
1 October 2016 at 22:00 #258771
Phil P
Participant
@philp
You should see a lot of disturbance on the surface of the fluid above each transducer.

A lot of people have un-realistic expectations of what these machines actually do, they seem to expect a grubby old casting to come out nice and shiny. This is not going to happen.

They are very good at loosening engrained dirt from a surface though, if you are cleaning brass parts you can get good results using one of the ammonia based clock cleaning solutions, this will brighten the brass as well as removing dirt (It will do this in any tank, but the ultrasonics speed up the process).

Phil
1 October 2016 at 23:29 #258776
Enough!
Participant
@enough
Posted by Bikepete on 01/10/2016 21:30:37:

Tried some kitchen foil and it was unaffected after 10 minutes…

How do you mean, "unaffected". If you hold it up to the light you should see tiny pinholes (may need a magnifier).
2 October 2016 at 11:21 #258823
Bikepete
Participant
@bikepete
Mmm, after a bit more experimentation all seems well and perhaps indeed some expectation adjustment was in order

Think the main thing confusing me was that with the basket in place the agitation of the water pretty much disappears – just some smooth ripples left. With basket out and less water in the tub then the vigorous agitation of the water as described above is very obvious. Doing the kitchen foil test and holding to the light shows pinholes (mainly on creases) after 30 seconds both with and without basket, so it doesn't seem to change the effectiveness much. Not sure why I didn't see the holes last night.

Just cleaned some oddments and it does indeed work – not quite blasting away rust etc as might have been hoped but it does loosen dirt and grime. Used fairly hot water from the kettle with washing up liquid again – might try some of the other recipes in future. Also, some gentle brushing/poking with an old toothbrush during the cleaning process to remove loose crud seemed to help.

Would probably go for one with a heater if buying again – as well as any cleaning benefit, having the item hot means water evaporates off pretty fast once removed, so less chance of rust.
2 October 2016 at 11:46 #258825
Ian S C
Participant
@iansc
I'v got a couple of small units, one was used by a beauty and nail therapist for finger nails(? removing artificial nails), the instructions say it must be used with the lid open( from what I can see, the person being treated would have difficulty if it were closed). Both of these little units just seem to buzz at 50Hz.

Ian S C
2 October 2016 at 11:52 #258826
Michael Gilligan
Participant
@michaelgilligan61133
Posted by Bikepete on 02/10/2016 11:21:01:

Would probably go for one with a heater if buying again – as well as any cleaning benefit, having the item hot means water evaporates off pretty fast once removed, so less chance of rust.

.

If you're thinking of trading-up … Please let me know what you want for this one.

MichaelG.
2 October 2016 at 12:16 #258832
Clive Hartland
Participant
@clivehartland94829
Lets be clear here, the Ultra Sonic cleaning action is by cavitation from the transducer and frequency, the medium is important. Water alone is OK but additional chemicals help lift the detritus and emulsify it ( Hold it in suspension)

Some are degreasing such as watch fluid cleaners and others are detergent. Small parts as said can be put in a glass jar with a small amount of volatile liquid, ie paraffin, white spirit for really dirty parts. Do not contaminate the main liquid by spills.

A lot of cleaning fluids are ammonia based with detergent additions.

Final cleaning is under hot water flow and a warm air drying. Printed circuits can be cleaned but only a short immersion ie. 1 minute whereas in normal materiels 3 to 5 mins. is adequate. careful drying of circuit boards is desired.

Optics can also be cleaned but again a short immersion time. Normal cleaning after with Ether and chamios cleaning sticks.

Clive
2 October 2016 at 12:24 #258834
Phil P
Participant
@philp
Just be careful if your wife asks you to clean her rings !!

Some precious stones have been know to be damaged by ultrasonics so I am led to believe.

Phil
2 October 2016 at 12:41 #258835
Bikepete
Participant
@bikepete
Thanks Michael, I'll be keeping it for now…

Just found the manufacturer's website BTW – seems new ones are expensive! There's also a downloads page which includes a PDF on periodic testing of ultrasonic cleaners. Sadly the pages are not in order, but it does describe the 'foil ablation test' in some detail, with some pictures of what to expect, alongside some other tests more relevant to medical use.
2 October 2016 at 16:30 #258854
Russell Eberhardt
Participant
@russelleberhardt48058
A few comments on recent posts:

"Russell, is your cheap Aldi unit as noiticeably active as this – I'm wondering if yours is a bit of a dud, or if I could achieve even better results with a proper unit."

I think my Aldi unit may have deteriorated with age. It is supposed to produce 50 W of ultrasonic power yet I have measured it's power input and it only consumes 40 W so I doubt if it would be producing mre than 20 W. Small items put in it do jiggle about a bit.

"A lot of people have un-realistic expectations of what these machines actually do, they seem to expect a grubby old casting to come out nice and shiny. This is not going to happen."

It depends very much on what cleaning fluid you use. The castings shown in Neil's article were cleaned using Allendale's Oxidation and Rust Removal solution. That is a 10 to 20% solution of citric acid so 1 or 2% after dilution – a rather expensive way to buy citric acid but effective.

"if you are cleaning brass parts you can get good results using one of the ammonia based clock cleaning solutions, this will brighten the brass as well as removing dirt"

Agreed, I have used Horoclean in the past, a mixture of ammonia solution with various organic solvents. For some reason it can't be exported.

"Optics can also be cleaned but again a short immersion time."

I would be a bit concerned about coated lenses having seen paint removed from metals. Have you tried it Clive?

"Some precious stones have been know to be damaged by ultrasonics so I am led to believe."

Yes, don't put pearls or opals in the bath. Any stones with cracks are liable to be damaged, especially emeralds. There should be no problem with other gemstones.

As an aside, I have found that washing up liquid isn't very good as it foams too much. Many American sites recommend using Simple Green whatever that is but I have a 5 litre container of detergent sold by Lidl for use with pressure washers and that works very well – add a dash of ammonia for use with brass.

Russell.
2 October 2016 at 17:46 #258868
Clive Hartland
Participant
@clivehartland94829
My use of the ultrasonic with optics is where there is oil that has gone into a prism mount and the prism is glued in place. A few seconds in the ultrasonic does clean out the oil. We in the instrument trade use Ether on small stick that have Chamois leather glued to the ends. This allows delicate cleaning into corners and close into edges of lens. Do not flood with ether as it will attack balsam and optical cements,. I have not seen it attack optical coatings though i am sure prolonged immersion would affect it. Fungus is the optical coating killer. For that we use Hydrogen Peroxide at 6 to 9 % rubbed on with a cotton bud.

We always did a degrease bath and scrub in white spirit first and a wash off in detergent and then into the ultrasonic. Do not let the white spirit into the ultrasonic fluid.

Clive
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