Ultrasonic record cleaners

FWIW,

One of keys to successful use of UT is bath management - how long is the bath good for use? There are a number of variables.

Detritus being removed from a record are either insoluble (i.e. particles) or soluble such as mineral salts and previous cleaners such as Dawn. The particles can be easily filtered, the soluble components not. What’s the work around to get maximum use of the bath? Well, most of the soluble detritus is ionic. If the cleaning bath is nothing more than water + nonionic surfactant and maybe a splash of IPA (which is nonionic) it’s very easy to monitor the ionic contaminant level - total dissolved solids (TDS) with a TDS meter - here’s a good one - Amazon.com: HM Digital 716160 COM-100 Waterproof Professional Series Combo Meter, 7", White/Purple : Industrial & Scientific.

So, if you are filtering with a good filter (book has recommendations), and a good 10" filter with a good pump may last for a year, a new bath will start at <1 ppm TDS, and I recommend bath refresh at 5-10 ppm, and most people get 2-4 weeks depending on how many records are being cleaning. Note: a 0.2 micron ’absolute’ filter will remove bacteria. And a 0.2 micron does not remove the surfactant - the surfactant micelles are too small (book Chapter IX Table X lists the diameters).

And the book does address no-rinse surfactant concentrations such as 50-75 ppm Tergitol 15-S-9 which is enough to get maximum wetting (critical micelle concentration) but no detergency. The residue thickness is not much different than the record surface roughness but if it is not uniform it may be audible by some people with very experienced/sensitive hearing. To get detergency with Tergitol 15-S-9 you need 135-150 ppm, but rinsing is recommended to prevent residue that may be audible. The book XI.7.2 and Table XVIII Residue Thickness from Cleaner address in further detail if interested.

Otherwise, there is always the brute-force approach to bath management - produce enough DIW to refresh the tank very frequently which is addressed VII.4 Home Production of DIW.

Devils in the details.

PS/As far as Lab-grade or Professional - it’s mostly nonsense. The P4875(II)+MVR5 (isonicinc.com) is nothing more than a 6L usable stainless tank with three 60W transducers which is the standard configuration for any of these that are using standard offshore sourced components and maybe assembled USA with bells and whistles that may add some cooling for electronics. The German-made Elmasonic P-series with dual-frequency Elmasonic P Series - Elma Ultrasonic Cleaners is a way different unit with cost and documentation commensurate. And then there are real industrial table-top units designed to operate 12-hrs/day such as Tabletop Ultrasonic Cleaners - Zenith Ultrasonics (zenith-ultrasonics.com).

@antinn 

What, in your experience, do you think would be the best combination of additives to the distilled water in a 180W 40kHZ ultrasonic 6L bath for cleaning LP's  (e.g. how much 91% isopropyl alcohol, Triton X, dawn dish detergent, or other.), and what time length would you think to be sufficient?
Thanks. 

@drbond,

If you were to download the book the answers would be in Chapter VIII, IX and XIV but I suspect you did not download the book.  So, accommodating this:

1.  First - Dawn may be a great dish detergent and safe for your hands and cleaning oil from birds, but for UT cleaning it's not appropriate.  There are some 20 ingredients CPID (whatsinproducts.com) of which only 3 do any cleaning.  Salt is added to thicken the product. 

2.  My recommendation for surfactant as previously stated is nonionic surfactant Tergitol 15-S-9  Tergitol 15-S-3 and 15-S-9 Surfactant | TALAS (talasonline.com) used 0.005 to 0.0075% (~0.5ml/6l tank) for a no-rinse concentration (wetting only) or 0.0135 to 0.0150% (~1-ml/6L) for a concentration (wetting & detergency) where the record will be post-rinsed.  If you want to stay with Triton X100, you need to increase the concentrations 3.5X.  Has to do with the difference in critical micelle concentration (CMC) discussed Chapter VIII with CMC details in Chapter IX.

3.  Because of liability issues I will only recommend 2.5% IPA which is not flammable and if using 91% IPA is 2.5/0.91 = 2.75%.  This small amount can have benefit by a process call soiled roll-up that is addressed Chapter VIII of the book. IPA at low concentrations 2.5% can assist cleaning by combining with low surface tension surfactants to improve the solubility at water-oil interfaces causing some organic soils to swell thereby allowing surfactants (in the cleaner) to lift the soil from the surface.  A solution of 2.5% IPA has shown to be complementary with very low concentrations of non-ionic surfactant added only for wetting (i.e., no-rinse).  HOWEVER:

VIII.8.8 Alcohol Evaporative Losses: Ethanol and IPA at low concentrations (<50%) are not azeotropes and can evaporate separately from water; and this is quite evident when reviewing the applicable vapor-liquid equilibrium diagram that when boiling shows the vapor vs the liquid concentration. At low concentrations, the alcohol vapor concentration is much higher than the liquid concentration. At higher concentrations when an azeotrope forms, the alcohol concentration in the liquid and vapor are the same. For those that may use Ethanol or IPA at low concentrations in an ultrasonic tank (use only at concentrations that are not flammable); over a period of time, the alcohol will evaporate from the water faster than the water evaporating. Unless the alcohol concentration is monitored (alcohol hydrometers are available), the concentration will drop if the tank bath life is extended.

4.  For length of time you want an equal number of rotations (i.e., no fractions) but at an accumulated time of starting at 5-10 minutes. Calculate the time = (number of rotations)/(rpm) so for example (20 rotations)/(2.5-rpm) = 8 min.  You can increase to an accumulated time of 15-min but much beyond generally provides no benefit.

Good Luck,

@antinn 

Thank you for the detailed response.  It looks like even on initial review that I could use 5+ oz of 91% IPA to get an approximate 2.5% solution in 6L. .. I am aware of alcohol's antibacterial properties, but I wasn't aware exactly what it did in the water bath:  your explanation explains it quite well.

Thanks!

@antinn 

I downloaded your book on an old ipad that is no longer used for anything with passwords, etc.  It looks to be a great resource.  Thanks to you and Bill for sharing that with the audiophile community!

Are you aware of any real world experience comparing the LP cleaning capabilities of an appropriately powered 40 kHz ultrasonic cleaning machine as compared to an appropriately powered higher frequency (120-200 kHz) ultrasonic cleaning machine?  And, along the same lines do you think that there would there be any real world difference in LP cleaning capabilities between a 40 kHz cleaner and an 80 kHz cleaner?  
Thanks.