Bottom paint mysteriously flaking off steel boat

Discussion in 'Metal Boat Building' started by Precious Metal, Oct 13, 2021.

  1. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    Lucks awfully like oxidised zinc
     

  2. Steelboat
    Joined: Feb 2022
    Posts: 73
    Likes: 11, Points: 8
    Location: Seattle

    Steelboat Junior Member

    I have had a similar problem with the paint failing directly underneath behind big plate zincs (8x12 inch). Mine use 1/2" stainless bolts with the heads welded to the hull, so the plate is about 3/8" out from the antifouling, 316 stainless star washers between the zinc and nut.

    The hack solution I use now is to grind the back of the zinc and actually paint it with epoxy primer. The sides and top of the zinc are bare of course. It still protects the hull, but has stopped the localized paint failure. Others have used polyethelene sheet under the zinc with success.

    I'm not sure if that is what's happening with your hull, just an idea.
     
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