Vacuum Record Cleaner Rreplacement

@lewm 

 I was  concerned about possible damage to the record surface when I first set up my ultrasonic cleaner. That is one of the reasons I looked closely at the effects of exposure time in the ultrasonic bath. For exposure times of up to 3 min in a static mode (which corresponds to 9 min on a rotating spindle) we did not observe any surface damage. At 4 to 5 min static exposure (which corresponds to 12 to 15 min in a rotating spindle) we did not detect any surface damage but  did detect diffusion of plasticizers, stabilizers or other additives from the bulk to the surface of the record. At  6 min static exposure we did observe possible evidence of some surface pit formation and possibly some rounding of the peaks on the groove sidewalls. This is not conclusive because it was observed with an SEM which could not analyze the same identical sample before and after cleaning (this is due to the preparation required for SEM analysis) unlike the other techniques we used.  

Based on these experiments, I never exceeded a 9 min cleaning cycle on my rotating spindle. Typically I used 6 min for newly acquired records and 9 min for previously owned records which might have more surface contamination. 

I would also state that the rotation speed of the spindle has an effect on the efficiency of ultrasonic cleaning. We observed that the cleaning efficiency decreases as the rotation speed increases.

@ljgerens

 I was  concerned about possible damage to the record surface when I first set up my ultrasonic cleaner. That is one of the reasons I looked closely at the effects of exposure time in the ultrasonic bath. 

This has always been a concern of mine and I never bothered to perform experiments as you have done.  I’m not sure what criteria I’d use to assess the damage.  Is visual (microscope) inspection sufficient?  Can you determine whether you’ve inflicted minor damage (not visible) but which will produce damage over multiple cleanings?

This raises a follow-up experiment:  multiple cleanings which are below the threshold of visible damage.  Would multiple 3-minute (static in your example, above) cleanings produce damage?  Can you trust your inspection with 100% confidence?

We seem to have annecdotal evidence from the large body of users that ultrasonic produces no harm, but there are so many variables (transducer power, distance from the record, number of records being cleaned per liter of fluid, etc.) that I don’t know how we can generalize across brands and methods.

After too many reported reliability failures with Audiodesk units, I discontinued selling them, and I’ve returned to my trusty Loricraft (dealer disclaimer).

As far as a rinse step is concerned, it absolutely makes a difference and I’ve heard it’s effect for well over 2 decades of comparison. 

If you’re not hearing it, then be content with your process.  You have one less step to worry about 

... Thom @ Galibier

@ljgerens

To compare these static exposure times to a rotating spindle, the time has to be multiplied by 3 because 1/3 of the record is in the bath solution at any given time

Thanks for your great experimental work!

I do query your rule-of-thumb factor of three.  I set my ultrasonic bath level so the bath is a bit below the level of the label.  Records are vertical in the bath, so the inner part of the grooves get less than a third of a turn in the bath, depending on where the actual recording stops.

Do you have any observations showing the influence of cleaning temperature?

I use both a VPI and a Humminguru. Humminguru 1st so all my drying is done on the VPI. Since the Humminguru uses so little fluid I rerouted the discharge to a tube and dump it into the VPI's waste jug and use a new US fluid batch every time. I found a marked measuring cup a better fill vessel than the Humminguru's container.

@thom_at_galibier_design 

Thom said "This has always been a concern of mine and I never bothered to perform experiments as you have done.  I’m not sure what criteria I’d use to assess the damage.  Is visual (microscope) inspection sufficient?  Can you determine whether you’ve inflicted minor damage (not visible) but which will produce damage over multiple cleanings?"

For these experiments two techniques, Optical Microscopy and Photoelectron Spectroscopy, were the primary techniques used to analyze samples for every cleaning condition before and after cleaning. Optical microscopy was primarily useful for gross contamination analysis such as large particles. No evidence of surface damage was ever observed with optical microscopy. Optical microscopy does not have the resolution to detect surface damage at the sub-micron level. Any evidence of such damage would require a more extensive use of Scanning Electron Microscopy (SEM). The SEM was not in my laboratory and does require extra sample preparation time so was only used on select samples. 

Photoelectron spectroscopy provided a quantitative analysis of the contaminants on the record surface. A number of additional supporting techniques were also used to identify specific contaminants on the record test samples.

Thom said "This raises a follow-up experiment:  multiple cleanings which are below the threshold of visible damage.  Would multiple 3-minute (static in your example, above) cleanings produce damage?  Can you trust your inspection with 100% confidence?"

From experiments on other polymeric materials, multiple short duration exposure to ultrasonic is less destructive compared to one long exposure. There are localized thermal effects that increase over time that can induce chain-scission and damage to a polymeric material. So short exposures would minimize such effects, This is one reason that a rotating record would lessen these thermal effects because part of the record is out of the bath at any given time. 

Yes, I trust our analysis 100%