Cleaning an anode

[landonshaw]

I have been inspecting my anode on the boat and outboard. All seems well. Outside of taking a wire brush to them now and again to clean, anything else worth doing?

[Pete7]

No, cleaning off any white stuff on it will be fine. If its corroding then its doing what its supposed to. Mine get a touch of the wire bush mounted in an angle grinder.

Pete

[landonshaw]

I could take the anode off th eoutboard, but the boat is in the water year around, maybe pulled on the hard once in awhile. But not if I can skip it. So i am left with the wire brush method. thanks Dave

[Andina Marie]

Cleaning an anode is nice for the cosmetics but it makes no difference to its functionality.

[Artif]

I find they last a lot longer with a good coat of paint on them

[landonshaw]

I thought they had to be clean to be functional?

[Artif]

Originally Posted by landonshaw

I thought they had to be clean to be functional?

Yes, they have to be clean to be functional, but you would be surprised at the amount of anodes I have seen with a nice coat of anti-foul.

[GordMay]

Originally Posted by Artif

Yes, they have to be clean to be functional ...

Indeed.
I hate to disagree with Yandina < Yandina Marine Electronics >; but, in this case, I will.
A Zinc Oxide (white rust) coating will isolate a zinc anode, rendering it totally ineffective.
Connect your ohmmeter between the Anode & Shaft, expecting to read continuity. High or infinite resistance confirms your visual diagnosis.
This is generally a bigger problem in fresh or brackish water, but also occurs in salt water.
Wire brushing, sanding, or scraping the surface only provides a temporary solution, and the oxide will quickly reform.
I would replace the anode, rather than clean it.

[Andina Marie]

True there should be no paint or insulating material on them however the white fuzz residue is sufficiently porous that there is no restriction to the conductivity of the salt water down to the base metal. Zincs that get no cleaning whatever are still depleted at the end of the season which would not happen if the residue insulated them.

[Andina Marie]

Originally Posted by GordMay

Indeed.
I hate to disagree with Yandina < Yandina Marine Electronics >; but, in this case, I will.
A Zinc Oxide (white rust) coating will isolate a zinc anode, rendering it totally ineffective.

Hmm I thought we were discussing the white fuzz that forms on the active surface of the zinc, not the connection to the shaft???

The only figure I could find on the conductivity of the zinc oxide was 1.4 to 2×10-4 Ω cm which is as good a conductor as the salt water or better.

If the zinc has come loose then by all means clean the shaft and install a new one.