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Aluminum pulleys seize on SS prop shafts at Mystic Aquarium

Hi, I maintain radio control boats at Mystic Aquarium. The boats are in a chlorinated pool which the public can operate from a console. The pulley(aluminum) on the propeller shaft(S/S), because of corrosion, cannot be taken off without removing the shaft from the boat which is very difficult. My question is: once I have the shaft off and the old pulley removed is there anything I can put on the shaft so that in the future I can replace the pulley without tearing the shaft out?

Albert Patalano
Maintainer at Aquarium - Mystic, Connecticut, USA
June 10, 2008

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June 28, 2008

You might consider having a pulley made of Stainless steel so that you don't have problems with electrolytic corrosion. There is an "electrical" potential between the two dis-similar metals (aluminum and stainless steel) and this will cause corrosion between the two pieces. If you match the materials (SS and SS), the electrical potential goes away and so does the corrosion caused by the dis-similarity.

In addition, you might consider using a zinc anode placed near the pulley and the shaft (just like the big boats do) to prevent corrosion of the stainless steel components. Just because the steel is a stainless steel doesn't mean that it won't corrode!

Hope this helps.

Jim Moss
- Boxborough, Massachusetts