@jtimothya
Dripping overnight allows the sediment to settle out. Almost all of it. |
Slaw describes this as a slurry, which is correct in every sense - I should have thought of that.
The slurry/sediment primarily collects at the bottom of the tank and most of the remainder collects in the dip of the drain tube. With 95% of the cleaning chemistry safely in the jug, I simply rinse out the tank and tube with pure water, second rinse with distilled, and re-use the chemistry.
Yeah, I’m a cheap SOB - and no, I haven't considered a filter because I don't think it would be as good. |
@jtimothya
It's only cleaner in terms of suspended solids, not in terms of soluble compounds. As Slaw notes, the yellow color fades to brown with use. After about 100 records, I change the chemistry. Arbitrary, but probably on the safe side. |
@antinn
The Tiger-Cloth arrived last week. Wonderful! Soft, adsorbent, easy to use. Can't imagine doing without.
Thanks !
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@jtimothya
Don't see why a mixture of frequencies should be better. There was a graph posted in the DIYAudio thread of cleaning efficacy vs frequency. For gaps the size we see on records, 40KHz is only marginally superior for the largest gaps, and quite inferior for the smallest. This mirrors my experience.
IMO, 40C is low - only a touch above body temperature. I often start a session with a temperature in the low 40's, but continue to begin 15 minute runs until the temperature hits 47C, when I wait for the chemistry to cool a bit. I acknowledge that it can be disconcerting to see your vinyl come out of the tank a little warped, but with uniform cooling in the rinse stage, the warp disappears. At least in my experience, by my standards. I use a 60RPM Vinyl Stack and running purified water for rinse.
Are you sure that your thermometer is accurate? And that it is monitoring the relevant temperature? Stir the chemistry vigorously - if the temp reading changes, then your tank is not homogenizing the chemistry and hot spots or cold spots may emerge with use. That could be affecting your perceptions of appropriate temperature. Hope that helps.
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Correction: substitute "particles" for "gaps". Should read "For particles the size ..." |
I also see that you are cleaning 6 records at a time, which means a spacing of at most 33mm. That spacing is OK for 80KHz, about 1.7 wavelengths, but, at less than a wavelength, that spacing is quite inadequate for 37KHz. Also, with 6 records your effective US power per record is down to about 55W. I find that I get better results at 75W. YMMV |
Thank you for the references, which mainly point out that there is very little formal research on US cleaning, beyond the obvious and the theoretical. Let me give you another reference: the Rushton thread (2016) here on Audiogon, to which I contributed extensively.
It seems that we mostly agree, but:
1) temperature. Your references suggest that low frequency US cleaning might be more effective at removing fats and oils. As I mentioned in the Rushton thread, I had thought so too until I found that it was a temperature effect. The lower frequency US did a better job of cleaning oils, while heating the chemistry more. When I controlled for temperature, the low frequency advantage disappeared. So I use 80KHz, sweep function, and 45C.
2) frequency mix - see above.
By the way, I have done a fair bit of trial and error, including 2000 odd records which were inadequately rinsed! So I had to do the whole lot again, with a better regime: rinsing under running highly purified water followed by a distilled water bath. Air dry in a clean-ish room.
By TDS I assume you mean total dissolved solids. I use distilled water for cleaning, so total dissolved solids is very low - for the first 2 records. Naturally that increases with each pair. That increase is roughly indicated by the colour of the chemistry, which is close enough for hobby work. For suspended solids, I allow the chemistry to settle and use the valve on the ElmaSonic to drip solid-free chemistry into a jug. I use VersaClean 2.5%.
By IPA, I assume that you mean isopropyl alcohol. I don't use anything volatile and flammable, because, while it is easy to monitor and regulate vapour in a lab, it is hard in a garage. Since my Elma machine can be an ignition source, I avoid the hazard. |
Machine is a rebranded ElmaSonic P60H (Fisher Scientific). My thinking was that Fisher is a lab supply company, and so the machine would have to pass two levels of QC. Still going strong after 6000 records, plus misc cleaning chores. Works wonders on wine glasses! |
@jtimothya
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.
With respect to frequency, my reasoning is as follows.
Bass response is a good analogy because both are sound waves in a confined space. Low frequency energy will be present in a listening room regardless of size - the problem is that different frequencies will manifest at different points. The mechanism is constructive and destructive interference. This is a function of reflections and dimensions (spacing).
If you want really good bass response down to a given frequency f, then the room should have at least one distance equal to or greater than c/2f, where c is velocity. Better is c/f, or even more.
By analogy, record spacing will affect the distribution of energy on each record surface. For a uniform distribution of energy (bubbles) which washes the entire surface, at least one wavelength is required. Consider the case of the US cleaner in Imperial measure, as it is more convenient. Then c ~ 5000 ft/sec = 60,000 in/sec. At a frequency of 60KHz = 60,000Hz, a wavelength is 1 inch. At 80KHz, wavelength is 6/8 = 0.75". Of course, records are not planes; they wobble on the spindle, they are slightly warped, etc. Therefore a safety factor of 1.5 to 2 is sensible, for 1 1/8" to 1 1/2" at 80KHz. I use 2".
By theory, the definition of energy is the ability to do work. The work in this case is microscopic bubbles on the surface to be cleaned. Since we know that low frequency US heats the chemistry much more than high frequency US, much low frequency energy is used to heat chemistry rather than clean. That is, the energy is expended elsewhere than on the surfaces. This is evidence that spacing matters.
By experiment, try cleaning a pipette in an ultrasonic bath. If anything is caked on the inside, it will take forever to come clean. The US agitation is negligible in such a confined space. Also, I tried close spacing and had to re-clean nearly a thousand records. I got as much suspended solids off during the second cleaning as I did on the first.
Your analysis of energy may well be correct. Thank you for enhancing my understanding of this by forcing me to think more about it. But in our practical case, it comes to the same thing - something is happening, so either we increase spacing (and reduce the number of records) or we reduce the number of records (and increase the spacing).
In conclusion, the direct evidence is: fewer records with greater spacing removed more solids. This experiment, however, does not differentiate between two potential causes: spacing and energy/record. Both interpretations of theory come to the same thing: fewer records, widely spaced, is better. |
@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 Thanks for your expert contribution.
@jtimothya What I do to gauge results is clean 50 records to the lower standard, allow chemistry to settle overnight, drain drop by drop, and note (e.g. photograph) the solids deposited on the bottom of the tank. Then I change chemistry, retaining a sample of the old, and clean the same 50 records according to the higher standard.
After letting the chemistry settle overnight and draining drop by drop, I compare the solids deposited on the bottom of the tank to the photo, and compare a sample of the newest chemistry to the old. The comparison is therefore of the lower standard to the increment of lower standard plus higher standard, which is approximately (in my experience) the higher standard.
Not precise, granted, but good enough for hobby work. Although I welcome R/Neil’s comment and correction.
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@antinn
So good to have a technical conversation free of snake-oil. Thanks!
I was wondering about your step 1: a fresh, low concentration bath for each cleaning session.
I use 80KHz near the maximum temperature for vinyl (45C), at a 2.5% solution of VersaClean, and, IIRC, a hint of oil can remain after 15 minutes, or even 30 minutes, even for the first pair in the series. This leads me to question a low concentration of surfactant.
But it could just possibly be bad memory. Your views? |
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@antinn
Hello R/Neil. Thank you for the long response. Much appreciated.
My filtration system gets me down to 30ppm of dissolved solids. I use that for rinsing before the distilled bath. Two questions:
1) Is 30ppm low enough to use for cleaning? (have been using distilled)
2) Is 30ppm low enough for polish?
Thanks!! |
@antinn
Not cheap - how true! But the specs looked good, formulated for plastics, and it was recommended by Fisher, so ... In any case, a better bet than Audio Snake Oil Formula 6 at $99/l. Too bad I didn't know an expert to ask before now.
IIRC - If I Remember Correctly - which I may not
'hint of oil' - as in a fingerprint
I was going to try soaking in 100% VersaClean for a few minutes and then trying US, but haven't got around to it. |
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