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Thread: aluminum corrosion.

  1. #1
    Member Magnum Man's Avatar
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    Unhappy aluminum corrosion.

    Im sure this has been talked about already but I before I bought my ol 81' wooldridge classic it sat dry for several years. And since I must cross saltwater to get to the river and I use it for fishing in the saltwater too Im fighting a losing battle against the white powdery corrosion. Its trying to totally take over the boat. In some spots it is pitting and turning into a grey crusty matter. I wash the boat every time I get back with joy soap and once I used a little ORANGE-SOLV aviation cleaner to brighten the aluminum but I mixed it lightly in a bucket of water as directed. Id like to whire weel or sand all the junk off but I think that would make it worse. The aluminum is fairly soft and not the same grade alloys as we see today. And my zinc doesnt seem to be taking too much heat either. Also my batts are grounded to the engine block and the ground bar under my dash is grounded to the hull and to the batts.

  2. #2
    Member Sobie2's Avatar
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    Default

    I live in Juneau, and have seen a fair number of older Aluminum plate built boats fall victim to your problem. Pitting is not good but the white powerder is in fact aluminum's natural protecting coating (just looks like bad). I've seen boats sit in the the salt water and just dissolve. Your best bet is to zinc the hell out of the thing, use the correct aluminum bottom paint, and dry it out. Alumunim oxidizes and creates the protective coating but it must be exposed to the air. But it your case it might be too little too late. Have a marine surveyor do an ultrasound on the aluminum to know its thickness and pitting to know if it is a problem.

    You don't want to be out making a crossing and break a seam or worse yet break in half.

    Sobie2

  3. #3
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    Not just any zinc either - get a big one with the aluminum "ears", and have the ears welded to your hull (on your stern, below waterline). You need good electrical bonding, and I am of the opinion that you don't get that with a bolted zinc.

  4. #4
    Member akrstabout's Avatar
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    Default Not sure about the batteries being grounded to hull.

    I wired my boat and made sure there was no contacts from buss bars or any accessory touching my aluminum hull. Lots of zinks on the out boards. Replace 4-6 every spring. I have not noticed any problems or anything. I am no expert but it is how I did my boat.

  5. #5

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    "the ground bar under my dash is grounded to the hull."

    Disconnect.

  6. #6
    Member MARV1's Avatar
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    Yeah, never grounded the electrical system to the hull of my boat either and it is 22 years old, no white powdery buildup either. I'd disconnect the ground from the hull.
    The emphasis is on accuracy, not power!

  7. #7
    Member AKBassking's Avatar
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    Default Dittos

    on the ground.

    I also every other year use a metal rubbing compound to brighten my boat up too and add a good layer of wax. There is also a product called Shark Hide that seems to work well too although it is $$$$. There was a thread about the stuff.

    ALASKAN SEA-DUCTION
    1988 M/Y Camargue YachtFisher
    MMSI# 338131469
    Blog: http://alaskanseaduction.blogspot.com/

  8. #8
    Member Magnum Man's Avatar
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    Thumbs up thanks

    I will disconnect the ground to the hull and do something to beef my zincs. Ive never used any kind of wax on the boat but sounds like it would make a good seal against the elements.

  9. #9
    Member AKBassking's Avatar
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    Default It works

    Quote Originally Posted by Magnum Man View Post
    I will disconnect the ground to the hull and do something to beef my zincs. Ive never used any kind of wax on the boat but sounds like it would make a good seal against the elements.
    mine is a 93 xtra Plus. It does have a little pitting, but that was there before I boaught it. When I take it out of salt water, she gets a wash inside and out.

    Each spring she gets a good rub out and several coats of wax!

    ALASKAN SEA-DUCTION
    1988 M/Y Camargue YachtFisher
    MMSI# 338131469
    Blog: http://alaskanseaduction.blogspot.com/

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