Record Cleaning Using Vacuum Machine for Cleaning and Ultrasonic for Final Rinse

@antinn how do you get from mass of pure dehydrated Tergitol to film thickness of 31 nm? Tergitol is something like a C33 hydrocarbon chain and generally hydrocarbon chains are around 1 nm thick (e.g., sugar). I failed to find any information on volume of dry Tergitol.

I guess you could calculate number of molecules in 315 ng of T (MW ~550-650 depending on T variant), assume size of around 1 nm2, convert LP surface to nm2, divide LP nm2 by #of T molecules and get stack of T molecules per surface area and assume that stack has unit height of 1 nm.

@billstevenson,  Bill, thanks for the clarification.

Take care,

Neil

@oberoniaomnia, 

how do you get from mass of pure dehydrated Tergitol to film thickness of 31 nm? Tergitol is something like a C33 hydrocarbon chain and generally hydrocarbon chains are around 1 nm thick (e.g., sugar). I failed to find any information on volume of dry Tergitol.

First is does not dehydrate, as a 100% concentrate - it's an oil with very low vapor pressure and a specific gravity of 1.006 g/ml TERGITOL™ 15-S-9 Surfactant which is essentially the same as water. 

There are a number of ways to calculate the record surface area.  A close estimate is the surface are of the flat portion, the groove area and the side-wall ridge groove area.  A simple groove length estimate is assuming an average groove velocity of the outer and inner grooves ((51-cm/s + 20-cm/s)/2) = 35.5-cm/s times a playback length of 20-min (1200-sec).   The average groove dimension of the 45-deg groove wall triangle hypotenuse is about 0.0016-inches so that each groove has about 0.0032-inches linear length that is about 0.0022-inch wide at the top and then add 10-15% for the side wall ridges,  Run all the numbers, and the surface area including grooves and side-wall ridges is approximately, close-enough, to 1-sq-ft, which make the film thickness analysis easier.  

The non-volatile residue (NVR) nominal film thickness (Contamination Control Engineering Design Guidelines for the Aerospace Community, NASA Contractor Report 4740, May 1996)  assumes the contaminant is uniformly applied and has a density of 1-g/cm³ = 62.43 lbs/ft³ (same as freshwater); and while a 1-micron film calculates to about 9.1 mg/ft², for ease of use 10 mg/ft² equals 1-micron thickness is used which is proportional.  Most water-soluble nonionic surfactants have a density very close to water, but much lower density contaminants will develop larger film thickness while denser contaminants such as hard water spots develop thinner thickness.  

I do a deep dive into the whole subject of “What is clean?” and for a record “When is a vinyl record clean?" in this free book -Precision Aqueous Cleaning of Vinyl Records-3rd Edition - The Vinyl Press Chapter XI which is pretty technical but given your background you should be able to wade through it.   

Enjoy,

Neil

@billstevenson 

I was going to post that the third edition is now on-line but you beat me to it!

By coincidence I spent the last few days cleaning my scant record collection though a cheap Chinese ultrasonic machine, 9 records at a time, having scoured Sydney to find Polysorbate 20 and Ilfoton.  By and large, the results have impressed me no end though obviously nothing can fix scratches. Clicks that have been audible on every play have magically gone away.

Only one record does not look spotless, and I think it was the one the police dusted for fingerprints after the turntable it was on was stolen around 1980!

I took several shortcuts which will probably horrify Neil.  For example, because Canberra's water supply comes from the Snowy Mountains, it is very clean, so I just used tap water passed through a Brita de-ionising filter instead of distilled water.  I just let the records air dry vertically in a rack after wetting in the Ilfoton bath.

@antinn I would like to thank you most sincerely for a truly impressive 'work of art and science' that obviously has been a labour of love for you.  In my opinion it is the most trustworthy document I have found through this forum.

The key is to buy your ultrasonic machine before the 5th.