Advice on using an ultrasonic cleaner please

[MJD]

I bought a load of contact lens storage containers which are an ideal size for holding most small watch parts. I was thinking of putting a part in each with some lighter fluid, screwing on the lids then placing them in an ultrasonic cleaner containing water.

Is that a sensible way to clean them?

Mike

[rehajm]

I only use the ultrasonic for case parts so I'll defer to others on how best to support small movement parts but in general you need the free flow of liquid to develop waves and cavitation needed for optimal cleaning, hence the basket that comes with most models and not a jar or closed containers. 

[Neverenoughwatches]

1 hour ago, MJD said:

I bought a load of contact lens storage containers which are an ideal size for holding most small watch parts. I was thinking of putting a part in each with some lighter fluid, screwing on the lids then placing them in an ultrasonic cleaner containing water.

Is that a sensible way to clean them?

Mike

Hiya Mike.  Contact lens cases are great for storage of small parts but i wouldn't use them for cleaning. They may not seal tight enough to prevent water getting into the case, depending whether they float or not but even so. And the plastic of the case may react with lighter fluid. Some plastics and rubber does degrade with naptha and could leach some composition into the cleaning fluid Some use those tiny glass jam jars, personally i prefer a larger glass jar with a parts holder inside loaded with a few mesh baskets. 

[MJD]

OK understood. Many thanks.

Mike

[spectre6000]

Additionally, the energy from the ultrasonic transducers needs to be able to pass through the medium. Softer solids (like plastic) are poor transmitters of energy, and will not work very well. There was a thread recently re: a study/experiment regarding the transmissivity of various materials in US applications. You can still get where you're trying to go, it just takes longer. The worse the energy transmission, the longer you have to leave it in there.

[Malocchio]

Alex Hamilton just made a video of the subject. Turned out the thickness of the glass container really makes a difference. Lab beakers were recommended because they are a lot thinner than jam jars. 

[mikepilk]

1 hour ago, Malocchio said:

Alex Hamilton just made a video of the subject. Turned out the thickness of the glass container really makes a difference. Lab beakers were recommended because they are a lot thinner than jam jars. 

I disagree. I have used regular jam jars (they are not thick) in the ultrasonic cleaner for years, and they are absolutely fine. I used to use thin beakers, but I now use jars with lids to reduce the smell. I didn't notice any difference in cleaning when I switched to jam jars. ( 5mins cleaner, 2 x 3mins rinse)

I put the parts in small mesh containers, sat in a plastic tray to make moving them easier.

Also I have used contact lens cases to clean the balance jewels for years. The cleaning is fine for jewels, but I probably would not clean other parts in them. If you try it without a lid (the water gets in) you can see the jewels bouncing around, so the ultrasonic does get through OK.

You can label them to keep upper and lower apart. I put literally 2 drops of solution in, and the case floats on the water. I have not seen any degradation of the plastic cases due to the solutions. The containers and lids the cleaning solutions come in are of similar plastic, as are the trays I use.

An Elma think plastic pots are fine :

 

 

 

Edited August 17, 2023 by mikepilk

[rehajm]

Yes, I appreciate Alex’s experiments and I did consider switching but like mikepilk I use a thicker mason jar and haven’t yet felt the need to switch. I do spend extra time pre-cleaning and depending on the project extend my wash times. I do wonder if switching would improve my efficiency but as a hobbyist speed isn’t much of a concern for me…

[spectre6000]

@mikepilk, @rehajmThe result of the experiment wasn't that thicker glass doesn't work, it just takes longer. I also use jam jars, and have honed my cleaning process to account for the thickness of the glass, and feel no need to switch to thinner glass. There are two dimensions of sonic energy: amplitude and frequency. Glass seems to transmit the frequencies just fine, but the amplitude is reduced at a rate corresponding to the thickness of the glass.

Plastics (there are various types) are softer, and not only attenuate the amplitude, but do so more aggressively at higher frequencies (those frequencies are absorbed, and turned into heat within the plastic). ABS, like what I think you'd find in a contact lens case (I wear glasses, and have never had contacts, but my few interactions with them passed through the soup of memory says ABS) is a very poor transmitter; it's very soft. The plastic watch cleaning pot pictured above is likely more along the lines of urea-formaldehyde plastic, which is so hard it rings when you tap it. Good transmissivity.

There's a method we use in luthiery to divine the acoustic properties of a given material (usually wood in our case) called a tap tone. If you suspend whatever it is with as minimal contact as possible with anything but air, then tap it lightly with something hard, the higher the tone, the harder and more transmissive. There's a lot more to it than that when it comes to picking guitar tops, but that's all you would need for an ultrasonic watch cleaning container.

[mikepilk]

10 minutes ago, spectre6000 said:

Plastics (there are various types) are softer, and not only attenuate the amplitude, but do so more aggressively at higher frequencies (those frequencies are absorbed, and turned into heat within the plastic). 

I realised this. That's why I only use them for balance jewels. They are small enough to bounce around nicely, and I always do a final hand clean of cap jewels with IPA on paper.

[MJD]

Fascinating information, thanks everyone.

Mike