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

Why balance and sharpen?

1. You will waste less power and have more speed with a properly sharpened and balanced prop.
2. Your boat and motor will last a lot longer due to reduced vibration.
3. Prop walk will be reduced.
4. Your boat, engine and radio will last much longer.
5. An unbalanced prop will cause vibration leading to
   1. Radio damage
   2. Crankshaft damage
   3. Drive line wear.
   4. Cracking of the hull
   5. Excess noise
   6. 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

1. a prop balance,
2. a fine mill file,
3. some sand paper
4. 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.

Email Brian