The sweet sweet sign of no bubbles, on the rim or screws at least.

Correction.  It leaks through the shaft area, which at this point leaves my o-ring to be at fault.  

I'm increasing the thickness of the o-ring by 20% and trying again.

I also set the complexity of the circle used to rotate_extrude that o-ring to 10 sides.  Will be easier to clean up and gives the tape something to grab onto.