The following experiments were done in my laboratory when I assembled my first ultrasonic cleaner for vinyl records.
Comparison of ultrasonic cleaning with manual cleaning and some RCMs:
The following cleaning methods were evaluated;
1. Manually scrubbing with a brush using distilled water and dish soap followed by rinsing with distilled water.
2. The original Spin-Clean record cleaner with the Spin-Clean solution.
3. Harry Weisfield's early VPI vacuum record cleaner using
distilled water, isopropyl alcohol and a non-ionic primary alcohol ethoxylatesurfactant.
4. A laboratory ultrasonic bath using distilled water and a non-ionic primary alcohol ethoxylate surfactant.
For these experiments, we used newly purchased identical records which were initially played and evaluated for SQ to make sure they sounded similar. They were then cleaned by the different cleaning methods and evaluated again for SQ. The general consensus was that the ultrasonic cleaned record had the best SQ by a wide margin followed by the VPI and finally the Spin Clean and manually cleaned were indistinguishable. We were surprised at the difference in SQ of the ultrasonic cleaned record compared to the other methods. It was like a veil was lifted from the speakers. We were immediately impressed by the improvement in detail and clarity of the ultrasonic cleaned record. Of course this is all subjective and we wanted to know if there was any measurable differences in the surfaces after cleaning with these methods.
The next part of this experiment was to use several different surface analysis techniques to determine the effectiveness of the various cleaning methods at removing known contaminants. A series of known contaminants (oils, greases, lubricants, hard water, finger prints, and peanut butter) were applied to specific areas of each record. Controlled heat (~ 120 F) was then applied to the records to drive off any solvents, simulate aging and induce diffusion and/or any chemical interaction which would make the contaminants more difficult to remove. The records were then cleaned with the various cleaning methods. The surface analysis of the contaminated areas requires cutting the areas into ~1 cm squares. These ~1 cm squares were then evaluated with several different surface analysis techniques. All of these cleaning methods removed significant amounts of surface contaminants but none produced a record with as clean a surface as ultrasonic cleaning. In all cases, ultrasonic cleaning removed significantly more surface contaminants than any of the other cleaning methods. Typically ~2% to 5% surface contamination remained on the ultrasonic cleaned records compared to ~15% to 50% contamination remaining with the other cleaning methods. The range depends on the specific contaminant and specific cleaning method. Some of the cleaning methods were less effective at removing certain contaminants.
The primary analytical techniques that were used to analyze these samples include: Photoelectron Spectroscopy (PES), Optical Microscopy, Thermal Desorption Mass Spectrometry (TDMS), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM).
