Prop Balancing and Sharpening

(the section on balancing and sharpening props is based on newsgroup
postings by USAHydro and others, the mistakes are mine)

Why balance and sharpen?
You will waste less power and have more speed with a properly sharpened
and balanced prop.
Your boat and motor will last a lot longer due to reduced vibration.
Prop walk will be reduced.
Your boat, engine and radio will last much longer.
An unbalanced prop will cause vibration leading to
Radio damage
Crankshaft damage
Drive line wear.
Cracking of the hull
Excess noise
Maybe whole boat wrecked when radio dies.
Most UK suppliers seem to offer a prop balancing service (£4 or
thereabouts), I have purchased and can recommend balanced and polished
props from Prestwich Models and Model Marine Supplies, the props from
Model Marine Supplies were almost a work of art.
Presumably the same is true in the states.

Balancing Props
Before going any further you should be aware that if you are working on
the Copper-Beryllium props, BE CAREFUL.
Copper-Beryllium is an EXTREMELY toxic compound. When you work on the
prop, only do so in a well-ventilated area, preferably with a vacuum to
remove the shavings and dust that comes off the prop. Be sure to wear
eye protection and a face mask. (USA Hydro) More info

You need
a prop balance,
a fine mill file,
some sand paper
and (optional) a craft drill.
Start by cleaning up all of the casting marks and parting lines, then
smooth the back side, do not remove material from the back side of the
prop. Where back refers to the back of the blade as on the boat, i.e. the
front of the prop faces the front of the boat.
Square up the trailing edge of each blade then put in on the balancer to
determine which blade is heavy. Slowly and carefully remove material from
the front side only, checking balance often until it is balanced.
Then sharpen and polish.
Re-check balance and repeat if necessary.