I ran exposed servos all the time. In the beginning when I was not that smart they were not warterproofed. It was a safty issue so I started waterproofing myself. I took the screws out and placed RTV in all three seems not getting it on the gears. RTV'd the screws and the servo wire going into the servo body. I also used a O ring for the horn. I work great but in the future if I run exposed servos again I will use Corrosion X.
The pic you see is a test of the servos. I placed both in water over night. Once dunked if you see air bubbles it not waterproof.
