4-Max
The Fixed Wing
Electric Flight Specialists

APC Thin Electric Propellers

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Notes on balancing plastic/nylon props.
Ream or drill the prop to the correct diameter if necessary. Make sure the prop is restrained when drilling so that the prop cannot rotate and injure you. Lightly sand the leading and trailing edge of the prop to remove any sharp flashing's.
Place the prop on the balancer. In most cases one side will drop, this is the heavy side. Rotate the prop by 180 degrees and see if the heavy side drops quicker or slower. If it drops quicker then rotate the prop by 180 degrees again, if it drops slower then keep it as it is.
To balance the prop, sand the front face of the heavier side of the prop until the prop balances horizontally. Alternatively you can spray clear car lacquer on the lighter side so that it is slightly heavier. When the propellants in the lacquer evaporates off it should balance horizontally. Check the balance again when the lacquer is dry and repeat the above if necessary. You have now balanced the blades but not the hub. This prop is only HALF balanced.

Next you have to balance the hub.
A fully balanced prop should not move when put in any position of 360 degrees.
If it returns to horizontal then the bottom half of the prop is heavier then the top.
You can either sand the bottom half of the hub or add weight to the light side by adding thick Cyano (superglue) keep sanding and/or adding weight until you can put the prop in any position and it doesn't move.

Now you have a FULLY balanced prop.