The alternative method, especially on small diameter propellers, is to leave the hub as it is and balance the blades. You can either add weight to the lighter blade, or remove weight from the heavier one.
To add weight to a lighter blade, tape can be added to the back side of the blade. This is a quick fix but you need to be aware that, with time, the tape will likely come off. But I have used this method and it’s worked perfectly well at my level of flying!
An alternative is to use paint or varnish on the backside of the blade; add a coat and recheck the propeller balance, and keep adding until it’s right. Be sure that you’re using a suitable paint though, one meant to be used on the material that the prop is made from.
You can also paint the tips of your prop white or yellow, which gives props a good safety advantage, and add more coats of paint to the lighter tip until it balances correctly.
To remove material from a heavier blade, carefully sand away the backside of the blade, close to the hub – keep your sanding to the inner 1/3 of the blade length. This is really only effective if the imbalance between blades is minimal. If your prop is very out of balance, look at adding weight to the hub or lighter blade first.
Above left: tape has been added to the backside of the lighter blade. Right: sanding the heavier blade is the alternative option.
Step 3: keep rechecking the balance after every alteration, you’ll more than likely find that very little weight needs to be added or removed to sort out the imbalance.
When the propeller balance is correct, the prop will stop rotating on the balancing tool at any position – it won’t necessarily rest in the horizontal position. If it stops rotating and then moves back the other way slightly, it’s still not balanced correctly.
Above: A correctly balanced prop will come to rest, at any position, without tipping one way or the other. Do not look for just a 3 o’clock – 9 o’clock position, as shown above.