Appropriate propeller balancing

[tieman]

Hi.
There are many examples (techniques) in the web how to balance propeller. Some people suggest to add some tape, some to use a sandpaper, some to add hot glue, but all of them have a common thing. Usually this is done on the bottom side of the propeller. But I wonder. "working side" of the propeller is the bottom one and in my opinion this side should be left "untouched". Can someone confirm if I'm right or it does not matter?

[mtesa]

I'm using this method:
fix the prop on a axle which is suspended on two strong magnets taken from broken hard disk drive.
axle tips are sharpened into a cone, so only one of those fine and sharp tips is leaning on a magnet and the other is suspended in magnetic field of second one. This assured minimal friction.
then heavier blade is sanded with 800 grain sandpaper and finished with 2000 grain paper.
then I set blades 45 degrees position to see if there is some balance issues with prop center hub.
and sand down heavier side again.

Works every single time

[tieman]

ok ... but on which side are you doing this? on the top of the propeller (where numbers are) or bottom? (maybe both of them?)

[mtesa]

I've been told to always sand back side of prop, as it less disturbs the airfoil