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

@billstevenson,  Bill, I am not sure if you took what I wrote in Chapter XIII out of context.

The records are vacuum dried because Neil reported finding 10%-30% residual solids left on the record surface using air drying techniques.  So it is important to get the debris off the record while it is still suspended in the cleaning fluid.  I use a microfiber towel to dry the turntable on the Cyclone between each side of the record during drying.

The blower-style vacuum-RCM (such as VPI) does not suck-up all fluid from the surface.  Anywhere from 10 to 30% is essentially dried/evaporated in-place.  So, it's important to final rinse after using cleaning solutions.  It's OK to use the vacuum to remove the cleaning solution and even if some is dried in place, the Alconox Liquinox pre-cleaner and the Tergitol 15-S-9 rehydrate and go back into solution when you rinse.  There is no reason to use a microfiber cloth to remove the cleaning solution.  

Let me show what happens with Tergitol 15-S-9 when its applied at the recommended 0.05% concentration = 500-ppm which also equals 500-mg/L (same as 0.5-mg/ml).  Let's assume you are applying 7-ml of fluid to the record surface:

1. If of 7-ml applied 0.05% Tergitol the worst case 30% dries in-place, that's 2.1-ml and at 0.5-mg/ml, 1.05-mg of Tergitol residue is on the record.
2. 7-ml of rinse water is applied, and now the 1.05-mg Tergitol is diluted to 1.05-mg/7-ml = 0.15-mg/ml.
3. If of the 7-ml rinse water (with some Tergitol) applied the worst case 30% dries in-place, that's 2.1-ml of 0.15-mg/ml Tergitol and now the Tergitol residue is down to 0.315-mg.  
4. Assuming the 0.315-mg is uniformly spread across the record, the residue thickness is ~0.0315-microns and this is down at inherent surface roughness making it inconsequential.  
5. If you wanted to be very conservative, you just do a 2nd final rinse

Hope this is of some help,

Take care,

Neil

I was in a hurry and did not explain myself well.  The record is taken out of the HumminGuru after the final rinse and placed back on the Cylcone turntable.  The top side is vacuum dried.  The record is removed and turned over, but before placing it back on the turntable to dry the other side I use a microfiber cloth to dry the turntable.  This just takes a few moments and prevents the dry side of the record from picking up any moisture.  Some people have expressed concern about using a RCM with a full size turntable because when the record is turned over if the turntable is contaminated in any way foreign material and moisture could transfer and adhere to the just cleaned and dried side.  With just a little care this possibility is easily prevented.

@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