Humminguru Nova

@elliottbnewcombjr 

You mention using propylene glycol in your cleaning mix.

https://www.amazon.com/gp/product/B0C4W8S79G/ref=ox_sc_saved_image_1?smid=A343O3SRMXM69V&psc=1

I would not recommend using propylene glycol in a cleaning solution for vinyl records. Propylene glycol can soften and swell the surface of PVC which makes it difficult to remove. If not completely removed, it leaves behind a sticky residue which can attract dust and other airborne particulates. 

Regarding record spacing in an ultrasonic bath. I assembled my own ultrasonic bath and I found no difference in cleaning efficiency between one record or multiple records spaced 1/2 inch apart. On my spindle assembly, I typically cleaned 10 records at a time with 1/2 inch spacing between them.

My ultrasonic bath solution only consisted of distilled water and a non-ionic surfactant.

@ljgerens

I think the generic US cleaners that you most likely used as a basis for your cleaner shoot the cavitation bubbles up. A purpose built machine has transducers facing the record surface. I’m sure you get your LPs cleaned but it’s just not as effective. 

@audphile1 

Yes, my ultrasonic cleaner had the transducers on the bottom. The cleaning efficiency for any contaminant examined was between 95 to 98% removal. Significantly better compared to other cleaning methods that we evaluated in my laboratory.

@ljgerens that’s great. What were the other methods?