On ultrasonic cleaners: does the speed they spin the records actually matter?

[Stack]

When I built my first ultrasonic cleaner for records, I found that longer than a few minutes in the ultrasonic bath had little beneficial effect on the overall cleaning process of records and the possibility of a detrimental effect. My initial experiments to evaluate several ultrasonic bath variables were done on sacrificial records that were cut into ~1 cm squares. These 1 cm square record samples had controlled amounts of various known contaminants (oils, greases, lubricants, fingerprints and minerals from hard water) applied to them. These samples were then heated in an oven to drive off any volatile species and to promote mechanical interlocking and/or diffusion into the record surface, which would make them more difficult to remove. These samples were then analyzed with several different surface analytical techniques before and after various ultrasonic cleaning variables. One variable was time in the bath. For these experiments, the 1 cm square samples were suspended vertically in the ultrasonic bath for various times. So these test samples were static and not rotating on a spindle as in a typical record cleaner. Typically > 95% of all surface contaminants were removed after 1 min of exposure which corresponds to ~3 minutes with a rotating record in an ultrasonic bath.

So even if the exposure time is much less closer to the label, I doubt that it would have little effect on the overall cleaning efficiency because most people are using run times of 10 to 15 minutes which corresponds to 3 to 5 x the time that I found for > 95% removal of contaminants.

Note 1: These experiments were all done using laboratory ultrasonic cleaners (Elma, Cole-Parmer or Emerson). Results may vary with different ultrasonic cleaners.

Note 2: The surface techniques that were used to analyze the test samples include; Optical Microscopy, Scanning Electron Microscopy (SEM), Photoelectron Spectroscopy (PES), Fourier Transform Infrared Spectroscopy (FTIR) and Thermal Desorption Mass Spectrometry (TD-MS)

This is very interesting. Thank you for sharing this!

May I ask what you found the best cleaning solution to be? I've been using distilled water with 2-3 drops of Tergitol in a 6L tub.

 

[Lou G]

May I ask what you found the best cleaning solution to be? I've been using distilled water with 2-3 drops of Tergitol in a 6L tub.

I found that just distilled water or deionized water in the ultrasonic bath worked surprisingly well at removing much of the contaminants on my vinyl record test samples. However the addition of a surfactant improved the cleaning efficiency of my ultrasonic bath in all cases. I experimented with several different non-ionic surfactants which were in use in my laboratory. I settled on several primary alcohol ethoxylate surfactants with the general structure R(OCH2CH2)nOH where R is the alkyl chain and (OCH2CH2)n is the ethylene oxide (EO) chain. I chose the lowest molecular weight ethoxylate that had the best solubility in water at room temperature. The primary alcohol ethoxylates that I used are similar in structure to Dow’s Tergitol 15-S series of surfactants which are secondary alcohol ethoxylates.

Just lowering the surface tension helps, but is not enough for optimum cleaning of a vinyl record. The goal is to get the lowest surface tension and some detergency. When surfactants in solution have reached the Critical Micelle Concentration (CMC), they undergo spontaneous self-association to form micelles. With the formation of micelles, dirt and oil can be solubilized and lifted off the surface and dispersed into the solution. In order to solubilize any surface contaminants, the surfactant/detergent concentration needs to be at or above the CMC. 2 to 3 drops of any surfactant/detergent in a gallon of water is typically not enough to reach the CMC. For my ultrasonic cleaner, I found about 1.2 times the CMC was ideal. This corresponds to about 10 drops per liter of distilled water for my ethyoxylate surfactant.

In summary for my ultrasonic bath, I used distilled water with 10 drops/liter of my non-ionic ethoxylate surfactant, bath temperature of ~36 degrees C, 2 RPM rotation and typically a run time of 6 minutes. I typically would clean 10 records at a time with a 1/2 inch spacing with excellent results.

I always followed up the ultrasonic cleaning with a distilled water rinse (which is critical to remove any residual surfactant) and spin drying.

For reference, the CMC concentration for several common Dow surfactants at 25 degrees C are listed below:

Dow Tergitol 15-S-9: 0.52 ml/l or about 10 drops per liter.
Dow Tergitol 15-S-7: 0.38 ml/l or about 8 drops per liter.
Dow Triton-X-100: 0.43 ml/l or about 9 drops per liter

The Library of Congress recommended recipe for a record cleaning solution consists of 2 ml of Dow Tergitol 15-S-7 in 4 liters of deionized water which corresponds to about 10 drops per liter.

 

[Hajidub]

Can't look at this microscopic topic as something that's large and real life. We're talking thousands of 1-micron (40Khz) bubbles exploding with enough voltality to create plasma. Unless your records have caked diamonds in the grooves it won't make a difference. Wanna know if your US is working, drop a sheet of aluminum foil in the tank for 15 mins, it's pure violence in there.

 

[Fishead]

@Hajidub, you are correct! It is literally a chamber of destruction with all those bubbles bursting and creating the movement of detritus from the record surface to the solution. In my way of thinking, there are some aspects of the process that bear prioritizing and are ideally provided for.

Firstly, do no harm. Then, be as effective and efficient as possible. The latter points are what have generated much interest and study regarding the solution in the tank. There are, needless to say, a great many opinions about that and the solution that @Lou G mentions is one that has, in various forms, become pretty popular because it seems to work quite well. For instance, my own "brew" consists of Triton X-100, Hepastat 256, and isopropyl 91% in a bath of distilled water. So, pretty close. I think it does a good job and is easy enough to concoct. It's also pretty easy on the pocketbook and that's always nice!

Further, I feel very fortunate that we have folks like @Lou G, experienced with the chemistry of it all and willing to take the time to share his findings. There was a time when a member with the handle Vince1 or guest110 created a thread that is a sticky now did much the same thing and gave us a great deal of good information about the subject. This "classroom" of sorts is what got me out of the being intimidated mode to actually buying a tank and getting started. Nothing has been of greater importance as far as the quality of playback is concerned because, as we know, it starts with the source and providing for the best possible.

So, it's a very interesting topic and will no doubt continue to generate productive discussion while we get our records sounding so dang good!!! Carry on, amigos.....

PS - For those interested, here's the precise concoction:



I make this concentrate and with the Hepastat 256, the Triton remains pure. I keep the main bottle of Triton in the fridge to retard any growth of micro-organisms. I can keep this at room temperature indefinitely until I'm ready to start another cleaning session. Add the ingredients to the distilled water and I'm good to go....

 

[bikspk]

I don't believe that it's the bubbles bursting that does the cleaning. Rather it's the bubbles collapsing and forming a localized high-pressure points.

Horribly complex subject but the pressure waves in an ultrasonic bath cause oscillation between high and low pressure where the amplitude of the oscillation is controlled by the power level of the transducers (eg. the volume).

When the low pressure of the oscillation goes below the vapor pressure of the liquid (water) you will get localized vaporization that forms the bubble where the succeeding high pressure wave can't collapse the bubble and it keeps on growing (through successive pressure oscillations) till it becomes unstable and collapses. The "violence" of the collapse is what's accomplishing the cleaning. Surface tension and whatnot come into play.

My first encounter with cavitation was in the Navy where low pressure areas of pumps and propellers were damaged by long term cavitation.

I don't recall seeing any reports about records sounding worse after they have been ultrasonically cleaned but have seen (and observe myself) many reports of improvements.

 

[drjohnnyfeva]

I hadn't considered this limitation, but it makes perfect sense. If you fill right up to the inner groove it's effectively a tangent point to the water line, which means... not much exposure, so this makes sense. It seems like I should be trying to fill up as close to the label edge as I dare.

I haven't had an issue with the labels getting wet on the Vevor, because it's spinning fast enough to where the water doesn't get a chance to drip down. I'm using 3 drops of tergitol in 6 liters of distilled water (less than recommended, but videos I've watched seem to say that less is more with this stuff, and to use the minimum amount possible to break surface tension), the water seems to stick to the grooves of the record as it comes up out of the solution but not the flat surfaces, so as it spins the water tends to stay on the playing surface only.

I've been US cleaning for a couple years. This thread is first time the short duration cleaning near label has been pointed out. To my memory, such as it is. Not much to do about it with Vevor style machines.
I pick an arbitrary cleaning cycle duration. 10 to 15 minutes. Records that don't sound as I'd like, get another cycle.

I've been doing the US cleaning for a few years now. There are a bunch of threads and only a couple times have the level of the US bath come into the discussion. I remember when I first started using it noticing that the bath level had to at least reach the inner grooves to the run off for that area to even get treated to the US. I've been filling it to that level all along. I've never done anything more than ear and eye tests when it comes to assessing the result of the US cleaning related to the inner and outer grooves. The sound is always better than before the cleaning and the vinyl itself looks clean and has a good sheen without any leftover fingerprints or marks - other than small handling damage on some of these older, used finds.

Also, there are label protecting spacer disks that are available... I've never used these as the labels do get wet, but I've not had any issues with pealing or damage... yet.

https://www.amazon.com/WEWU-ROUNDS-Cleaning-Protector-Waterproof/dp/B09DY5GH27?th=1

There was also a guy here making the whole mechanism to fit multiple tank sizes with this type of spacer before I ever saw them anywhere else. ETLS's Record Rotisserie - I followed @onwardjames thread from the beginning along with another long one that started with the question, "Have you ever used wood glue to clean an album?" Fun times, and a good read too. The US thread where the rotisserie is mentioned is here:

https://audiokarma.org/forums/index.php?threads/us-so-simple-even-an-onwardjames-can-do-it.964264/

The other detail that hasn't been discussed here is the number of records and their proximity to each other on the spindle of the US. If I only have a few LP's to clean, I'll do 2 at a time with more space between them than when I have a lot and clean 4 at a time. I think the fewer LP's is better. I have no empirical evidence of this, but I have never needed to do a second 15 minute cycle on a two LP cleaning, while I have run another cycle on a 4 LP group a few times. There's also a bit of discussion in that above thread about a power supply that you can control the rotation time if you happened to get a unit as I did with a motor that only had one speed. So time in the bath was discussed there too.

 

[Fishead]

I don't believe that it's the bubbles bursting that does the cleaning. Rather it's the bubbles collapsing and forming a localized high-pressure points.

OK, so the reverse of what I and likely many have been thinking.....in either case, the action seems to rid the grooves of whatever might be stuck there and hence we experience a more noise-free playback, which is the objective. Thanks for the clarification, @bikspk!

The other detail that hasn't been discussed here is the number of records and their proximity to each other on the spindle of the US.

Yes, I don't recall reading anything about that in this thread, but it has certainly been discussed in others previously. I also don't remember if the evidence was empirical, but something about either 3/4 or 1 inch between records is what I believe was suggested as ideal. Many, however, have cleaned with less space and had good results as well......does leaving a bit more space improve things? Some say so......as for me, VinylStack, when they were still in business, made that a non-issue when I purchased my setup from them as the spacers do indeed dictate that distance as 3/4 inch, so there's that.

You know, I'm just OCD enough that the matter of cleaning the entire record surface made a lot of sense to me. My first couple tries, filling the tank just past where the grooves ended, resulted in a nice, shiney clean record except that the runout area was still looking pretty shoddy. I just couldn't tolerate that, so I began filling the tank to where I could submerge the entire thing, right up to the label, which was of course protected by the spacer with the nice rubber o-ring, and my results were absolutely more eye-pleasing so I've stuck with it. If you have no way to protect the label, it could become an issue though if you start seeing damage to it. Most comment that the label remains intact, but I suppose that might vary from label to label so caution would best be advised.

 

[Old Guy8]

I use these spacers with o'rings on one side. Bought from Isonic. ( Have no connection to them. ) They are about 5/16" thick. Need two between records.
If I have few or really dirty records, I space farther apart with additional spacer(s) between. 2 or 3 record load. Instead of normal 4.
I fill up last few ounces, close to spacers, after first load of records are loaded.

I suspend a thermometer in tank. Tank sometimes gets much warmer than where it's set, when first load is run. Before eventually lowers closer to set temp.

 

[Fishead]

Tank sometimes gets much warmer than where it's set, when first load is run.

I have noticed this as well and believe the transducers generate a fair amount of heat themselves. My experience is that the temperature gradually climbs with each load I'm doing but rarely gets much over 38deg. C. I have seen 40deg. on occasion but again, in my experience, nothing untoward occurred with my records although some have said they see a slight warp that flattens upon cooling. I have not seen that, but perhaps with thinner records this may be more likely? Not sure.....the one thing I have stressed in the past is that it is important to check the display temperature of the tank, if you have such a feature, against a know to be good independent thermometer. I've had 4 tanks and 3 have been off by as much as 5 deg. The one I'm currently using is spot-on, however, although I do still check it from time to time......carry on amigos

 

[Lou G]

Regarding the spacing between records in an ultrasonic bath, I typically would clean 10 records at a time with a 1/2 inch spacing with excellent results. I already knew that spacing < 1/4 inch had no measurable effect on the cleaning efficiency based on previous experiments with Si wafers in a static mode and CD blanks (polycarbonate) on a rotating spindle. I was interested in cleaning up to 10 records at a time which required a 1/2 inch spacing on my spindle. Just to be sure that the groves on the record surface did not have an effect on the cleaning efficiency, I did an experiment with a sacrificial record in the bath spaced 1/2 inch from a vinyl blank. Several different known contaminants were applied on both sides of the record in different areas. The ultrasonic bath was run for 3 min. The test record was analyzed with several analytical techniques and no measurable difference was observed between the outside of the record and the inside which was spaced 1/2 inch from a blank. In both cases complete removal of the applied contaminants was observed.

 

[drjohnnyfeva]

View attachment 3496199
I use these spacers with o'rings on one side. Bought from Isonic. ( Have no connection to them. ) They are about 5/16" thick. Need two between records.
If I have few or really dirty records, I space farther apart with additional spacer(s) between. 2 or 3 record load. Instead of normal 4.
I fill up last few ounces, close to spacers, after first load of records are loaded.

I suspend a thermometer in tank. Tank sometimes gets much warmer than where it's set, when first load is run. Before eventually lowers closer to set temp.

My US cleaner came with plastic disks that look like they might be 3d printed or some basic plastic material like it. No gasket around the edge to keep water from the label. Before buying something like the Amazon one linked above, I might just McGyver a silicon caulk bead around the edge, let it dry and see what happens.

 

[Old Guy8]

My US cleaner came with plastic disks that look like they might be 3d printed or some basic plastic material like it. No gasket around the edge to keep water from the label. Before buying something like the Amazon one linked above, I might just McGyver a silicon caulk bead around the edge, let it dry and see what happens.

Or silicon caulk at a few spots, large O'ring, to surface. They should seal when compressed. Or use a flexible glue to adhere o'ring.
I've not tried this. Just idea.

 

[onwardjames]

I'm not sure if @ETLS is still doing his thing, but man, I sure love what he created. Works ridiculously well.

Keep them clean slabs of wax spinning, everyone.

 

[bikspk]

Regarding the spacing between records in an ultrasonic bath, I typically would clean 10 records at a time with a 1/2 inch spacing with excellent results.

I'd always limited myself to 4 records at a time in a cleaner with a 6-liter capacity. The nylon spacer I fabricated (this is a diy rotisserie with an arduino controlled stepper motor to control rotational speed) were about 1" long so that's what I ended up with.

Seeing as I usually clean a box of 75 records at a time and it appears that there is evidence that the filling density is less critical than I'd thought I might shorten my spacers and try cleaning more.

I also have my own 1-gallon water distillation unit and try to keep a good supply of distilled water on hand. Makes economic sense at my volume.

 

[Jdanderson02]

Came to the AK forum to share my experience with the Vevor US record cleaner. Long story short, amazing. Makes old records new again. Far beyond any expectations I had for improving sound quality. The spindle will hold eight, but I double the spacers and clean four at a time for no reason other than preference. Relative to spin speed, I use the default speed of the included rotisserie in a 30 minute bath of distilled water at 32 degrees C. My scientific cleaning solution is about a cap full of the stuff that came with a Spin-Clean, although the first several records that I cleaned were only in distilled water. and were great The results are so good that I don't feel the need to change anything. Can't imagine that the speed of the record will improve on the results I have seen. My $.02