RE: Balancing Mejzlik Props?
I stopped using Mejzlik along with several other pilots at my club. The last three I had took way too much work to get them balanced. The third was so bad it was unusable. Many of us have switched to Bolly wood props and they seem to be much better and require little or no work to get them balanced.
I use automotive clear coat on the front of the blade to balance the tips, and the same on the hub if needed. You should never sand on the back of the blade. It is too easy to change the pitch.