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Thread: what anodes to use?

  1. #1
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    what anodes to use?

    mostly fresh to an occassional brackish run. it might sit in the fresh water for a day or two 3 tops and the brackish water for an overnighter.

    zinc?? or Magnesium???

    Thanks
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  2. #2
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    I would say magnesium.
    Just because something's old doesn't mean you throw it away !

  3. #3
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    MC
    Thanks is there any issue with mixing both? There are 2 on a Volvo 280
    One is a bar at the bottom of the transom plate. And the other is by the prop shaft. I can find the bar in mag. But not the one by prop shaft

    I don't want to create a battery should I go with both in zinc until I find them in mag. ?
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    Not that it should make much difference , I didn't know you were talking about a Volvo .. It's been a l o n g time since I did zincs on a 270/280 .. I didn't know that there was options other than zinc available now.

    Personally , I wouldn't mix them. Those units are so good that the only example I've ever seen of an electrolysis issue on one was where the owner had used coppaslip on the splined drive shaft and the throwoff went on the inside of the housing and got wet with salt water.

    The zinc might be a bit slow to react in the water you describe though if it is called on to neutralise any galvanic activity.
    Just because something's old doesn't mean you throw it away !

  5. #5
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    Price is a big difference too. I can get a set both anodes and new hardware in zinc for $25. The mag bar alone with no hardware is $40. I think I'll Zinc
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  6. #6
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    And to think the things are supposed to fall apart too ! haha

    Personally , I think you'll be ok .. just maybe monitor things to make sure the boat doesn't actually have any self inflicted issues or you should end up in a 'highly active area' unknowingly .
    Just remember Phil's advice .. always make sure the grounding surfaces are clean and bright .
    Just because something's old doesn't mean you throw it away !

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    I've never mixed annodes, but I would think if you did you would at best use up the mag annode quickily as it would not only be protecting the drive, but the aluminum annode as well. I suppose once the mag was used up the aluminum would then start doing it's job.

    Worst case, the aluminum and mag would themselves react and create their own current flow. Not sure on that though; seems like the former is the more probable scenario.

    Here's a handy link about annodes, but no mention of mixing aluminum and mag.

    http://www.performancemetals.com/anodes/AnodeFAQs.shtml
    Don
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  8. #8
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    I would think you would want aluminum anodes which are designed for brackish water. Magnesium is only for freash, and zink is only for salt. Aluminum will hold up well in both.
    Donzi 18C
    Donzi 25 ZX "Full Tilt F/B "

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    Judging by his post , it doesn't sound like Matty has an aluminum option .
    Plenty of the two zinc styles he needs and only one (expensive) magnesium one on hand with the option to shell out mucho $ for another mag one ... or more .
    Just because something's old doesn't mean you throw it away !

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    "Is anyone here a materials scientist?!" (or something close to that. ) -Seinfeld


    Some fun reading, that doesn't fully answer the question in my view but might get part way there: http://www.corrosionist.com/Galvanic_Corrosion.htm
    "I don't have time to get into it, but he went through a lot." -Pulp Fiction

  11. #11
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    stop the presses I did find these in alum.

    http://www.ebay.com/itm/Canada-Metal...#ht_2658wt_905


    the first pic is where the prop anode goes around the prop shaft housing, in the second pic the dog bone about 6 inches long attaches with two bolts to the bottom of the trim ears you can see the bolt holes below where the rod for the reverse latch should go.
    Attached Images Attached Images
    Last edited by mattyboy; 03-23-2012 at 01:31 PM. Reason: added info
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  12. #12
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    marine parts source in TN had the mag. ones for less than $15 each
    When the sky is grey,look out to sea.
    When the waves are high and the light is dying,
    well raise a glass and think of me...
    When I'm home again,
    boys, I'll be buying!

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    Come Join Us on The Queen Of American Lakes



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  13. #13
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    Check out www.boatzincs.com/volvo_penta-aluminum.html
    That's where I got the aluminum ones for my 280T
    1978 X-18, SBC, Volvo 280T
    Big Grizzly 21 Solas Prop
    Heart Bay, Lake George, NY

  14. #14
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    Sounds like shopping around pays off again !
    Just because something's old doesn't mean you throw it away !

  15. #15
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    they were always there It was just the way I typed the search on ebay one way had like 6 items the other had like 100 items
    When the sky is grey,look out to sea.
    When the waves are high and the light is dying,
    well raise a glass and think of me...
    When I'm home again,
    boys, I'll be buying!

    My Ride

    Come Join Us on The Queen Of American Lakes



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