Thumbs up for ultrasonic record cleaning

All,

An inherent problem with using ultrasonics to clean PVC is that as a plastic, it is going to absorb ultrasonic energy  http://www.zenith-ultrasonics.com/part_positioning.htm, and https://techblog.ctgclean.com/2011/11/reader-question-baskets-for-ultrasonic-cleaning/, noting that John Fuchs with Blackstone ultrasonics has been in the business of UT cleaning for over 25 years, and is a recognized expert.  This is a good article addressing some of the basics written by John Fuchs, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19950025362.pdf.

If you overload the UT tank with records, you are going to significant reduce the power available to clean.  Note UT came into promenance 25 years ago when the elimination of CFC solvents forced the industry to develop environmentally suitable aqueous cleaning solutions.  But, this was mostly for metal cleaning.  You can compensate the high plastic load with more power, that is variable, but you are talking industrial units starting at over $2K.  Check the units at Blackstone and Crest Ultrasonics, these companies have been manufacturing USA made UT tanks/consoles & systems for over 25 yrs. 

@antinn

Thank you! That explains why power per record a relevant parameter. If I had ever known that, I had forgotten. Just like I had forgotten some of the basics (i.e. how cavitation bubbles form).

@antinn,

You're post seems to confirm what I heard in my experiments.

@antinn 
Thank you for your interest in this topic and your contributions.

Fwiw, we are talking about units costing more than $2k.  At least I am; I don't know what Terry9's machine cost.. I tried the cheap Chinese route and it proved unreliable.

If I'm willing to spend a lot more time with a lot more mess, I can get a record as clean with a one-at-a-time horizontal machine and enzymes (eg Loricraft and AIVS) as I can an ultrasonic with filtering.  My goals were to maximize throughput, reduce the time needed to spend on cleaning while still obtaining clean records.  My setup and technique are designed to meet those goals. 

Your comments seem largely related to sizing.  I'm sure we can agree that issues will occur with a rig improperly sized to do the job that one asks of it. Generalities warrant assessment against specific set-ups.

An inherent problem with using ultrasonics to clean PVC is that as a plastic, it is going to absorb ultrasonic energy

Everything vibrates and everything absorbs energy. That PVC absorbs energy is not an inherent problem to the use of ultrasonics for cleaning records, at least to the point that whatever "problem" may exist is not a deterrent to its use.. The successful use of ultrasonics for cleaning records - and it can be successful - is demonstration of its efficacy.

There is no standard for measuring what counts as clean. There is no effective way to compare techniques or methods.  You cannot clean the same record twice.  When do you stop cleaning?  My rule is: if it sounds clean it is clean.

I'm familiar with Fuchs and Zenith and consider them knowledgeable resources. Apart from observing that plastic baskets absorb energy, It is unclear how basket design is relevant in the case of cleaning records which uses no basket.

If you overload the UT tank with records, you are going to significant reduce the power available to clean.

There are many sized tanks. This statement begs the question.  As Fuchs points out tank size, surface area, proximity to transducers, etc. are relevant.  So what counts as overloading?  This argument simply says a tank is overloaded when there is a significant reduction of power availalbe to clean.. 

Energy asorbed within the tank is not the energy used to power the transducers whose output is independent of what is absorbed. If the tank and its transducers are insufficient to do the job then there's a sizing problem.  It's not like absorbed energy reduces the overall energy in a tank at a given time.  Transducers continually cavitate, continually cause the creation of vacuum bubbles for the length of a cycle.  Records continually rotate across working transducers.

@terry9

Your example of particle size is unconvincing to me. A ’visible glop’ is made up of tiny particles which can be broken loose by US action, and then either deposited as solids or taken into solution as solutes, or perhaps even suspended. It is not necessary (or desirable) to remove the blob of glop all at once - a 1/4" glop would respond best to a frequency so low as to be reminiscent of a file.

Okay. Given enough time leaving an object in a constant stream of water will often result in a clean object. Exposed to the milder implosive power of more small bubbles coming off a higher frequecy may remove a substance - given enough time. But I don’t want to think about the composition of the dirt on a record or continually vary the time of a cycle according to that composition. Through trial and error I arrived at 10 minutes at 80kHz and 10 minutes at 37kHz - and that works. Rarely do I need another cycle.

Wrt the whole wavelength isse, which I see as largely theoretical, hopefully we’ll just agree to disagree. My dual frequency approach can process 5-6 records in 20 minutes and I’m quite satisfied they are clean. But I’m not a dogmatist, I will try using an extra spacer and 4 records though I’m uncertain how I would gauge results unless there is a significant difference.

The use of multiple frequencies within a cycle is common practice for industrial ultrasonic cleaning - I read no articles that talk about wavelength, for example specific item spacing for 40kHz, which is probably the most common frequency used.

When f=.037MHz and c=1480m/s (water)
Wavelength=40mm
My spacing is ~31mm.

Thanks for your engagement on this topic. I appreciate your interest.