Thumbs up for ultrasonic record cleaning

@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?

@terry9 

The Fisherbrand™ Versa-Clean™, is a broad-base cleaner, with a combination of surfactants and corrosion inhibitors and some alkalinity, and the recommended concentration for use is not less than 60:1, but as much 10:1.  The product details are pretty limited, and although it says concentrated, it is actually a diluted form of very concentrated surfactants.  There is no way to know if a 2.5% solution will achieve the lowest surface tension.  So, 2.5% (40:1) may not be enough, but its not cheap.  And what is IIRC?  When you say a hint of oil are you talking about oil as the original contaminant on the record.  

The Tergitol 15-S-9 that I use for a cleaning solution is very similar to what the US Library of Congress uses to clean delicate shellac records, and is a non-ionic water soluble surfactant.  It is a replacement for Triton X100 that you may often see discussed in these forums, and has the same performance, but at 1/3 the concentration and is not an evironmental hazard.   Tregitol 15-S-9 is very concentrated and is quite cheap, a Qt is $38.70 and at about 4ml/gal https://www.talasonline.com/Tergitol-15-S-3-and-15-S-9, would make about 250 gallons of cleaning solution.  

A similar product to the Fisher Versa-Clean is Liquinox, https://alconox.com/liquinox but it is likely more concentrated since it only requires 100:1, and at that concentration it will achieve a low surface tension of 29, but it is anionic and will foam.

R/Neil

@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.

@terry9 

The Alconox Liquinox cleaner has been around for many years, and is very well doucumented. The company Alconox has a lot of data available, most of the ingredients are specified, and Liquinox is available Amazon www.amazon.com/Alconox-Liquinox-Critical-Cleaning-Detergent/dp/B003FZAQKG?th=1, $21/Qt, $67/Gal, which at 1:100 dilution makes it pretty cheap.  Read the application notes here https://alconox.com/resources/standarddocuments/tb/techbull_liquinox.pdf

Post rinse with these products is absolutely necessary to prevent leaving cleaning residue behind, and Liquinox recommends flowing water for rinse, and states "For critical cleaning do final or all rinsing in distilled, deionized or purified water."  Note that these products (Liquinox) are not that much different from household dish detergent such as Dawn, designed to mix with tap-water, except they are fragrance-free, and the ingredient concentration is formulated more for the industrial and medical sector.

My use of Tergitol 15-S-9 mixes it with DI water and uses a soft nylon record brush whose bristles do not penetrate deeply into the groove, and nylon softens when exposed to water so very limited risk of record harm.  But a brushing action develops a lot of agitation, so I can get away with just a single Non-Ionic Surfactant.  For ultrasonics - you have the cavitation, and this is excellent for blind holes and inaccessible surfaces, but use for records that have no inaccessible surfaces is really about efficency, except for deeply embedded partcles that may be removable with heated ultrasonics.

Good Luck,

R/Neil