Anodes???

[Wardy]

Total newbie here... But what are anodes?

Here's my guess... They are lead discs bolted to metal parts of the understructure of a boat. With the interraction of salt water they act like batteries creating a current that... maybe deters organic growth?

Well, what is their real use?

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[Rick]

Close - sacrificial zinc anodes (salt water) or magnesium anodes (fresh water) that result in underwater metals being cathodic - the anode wastes away to protect the underwater metal of the boat - prop shafts, thru-hulls, propellors etc ...

Anti fouling paint is used to keep organics at bay ...

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[mirabriani]

I recently discovered some white powder inside my keel case. It seems to have occurred between the aluminium slave cylinder for the lifting keel and the (stainless?) steel mounting bracket and bolt.
The question which occurs is on which metal do I fit the (zinc?) anode?
Or do I use that sticky yellow stuff to isolate the bolt?
Thank you in advance for any advice.
Briani

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by mirabriani on 20/07/2004 09:17 (server time).</FONT></P>

 

[Stemar]

I'n no expert, but fwiw, since no one else has answered, here's my 2 penny'th.

The white powder is probably corrosion from the aluminium. A generous dose of the yellow gloop (I can't remember what it's called either) to separate them may well help.

Unless the assmbly's immesed in sea water much of the time, an anode is unlikely to help, even if you can fit one directly to the cyliner

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[mirabriani]

Thank you for your thoughts.
I will give it a try
Briani

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[VicS]

I agree with Stemar. The yellow paste is zinc chromate and I think its trade name is Duralac. You should be able to get it from a rigger. Take the st st bolt out coat it with the paste and refit. You will find that the quantity of corrosion product, aluminium oxide, is out of all proportion to the amount of metal loss but nevertheless you should do something about it.

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[VicS]

Stemar has it right. The yellow paste is zinc chromate and I think the trade name is Duralac. You should be able to get it from rigging specialists. Take the bolt out coat it with the paste and refit. You will probably find that the volume of corrosion product is out of all propotion to the amount of metal loss but you should not ignore it. Zinc chromate is carcinogenic so best to wear gloves.

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[sailorman]

R these fitted to a 58 ft MoBo with a big key!!!!!!!!!

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