Haulout Workplan & Order of Operations?

Discussion in 'Metal Boat Building' started by NorCal, Sep 24, 2013.

  1. NorCal
    Joined: Nov 2011
    Posts: 19
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    Location: California

    NorCal Junior Member

    Boat - 1970 38' River Queen Houseboat

    Background - Hit a submerged object on Labor Day forcing my hand on an overdue haulout of my 38' River Queen Houseboat.

    Now that she's on hard I've noticed some patches that I would like to cut out and replate properly as well as some location of pack rust where plate overlaps in the bilges and was not sealed.

    The boat was free and I grew up in a metal shop welding so I think I can handle the repair, if not I can always call on one of the pros I've known for most of my life. With that said, what order should I approach the work to get the best end result?

    1.) ultrasonic sound the hull
    2.) cut out the bad and replate
    3.) abrasive blast
    4.) Zinc-Chromate epoxy primer
    5.) Bottom coat - coal tar epoxy?
    6.) Bilge coat

    All in all the hull is in solid shape. There are two spots that look think and are simple enough to cut out and replate. My concern is that blasting will expose more areas that need repair. That said I want to have a proper coating at the end of this haulout and am worried that if I blast then prime the next coat will be flawed.

    Appreciate the help in advance.
     
  2. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    You spot corrosion from the inside. Flashlight on your hands and knees. Metal boats rot from the inside out

    Sandblast bottom and epoxy prime each panel as its blasted. Choose a primer with a long overcoat time. Build the correct film thickness. If working outside do not allow morning dew to run down the sides and contaminate to bottom coatings.

    Use a commericial epoxy primer. i use international. Speak to your local paint technical diretor.

    Coal tar is old fashion and has defects. Dont use it.
     
  3. NorCal
    Joined: Nov 2011
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    NorCal Junior Member

    So blasting one section at a time followed by priming is what you would recommend? How do you protect the freshly primed surface from being contaminated with blasting dust?

    Do you also recommend international for the other coatings?
     
  4. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    Yes.:eek:ne panel at a time. A simple plastic sheet protects against dust. The key to a good job is the initial coat of epoxy on clean white steel. Dust contamination between epoxy coats is insignificant.

    Speak to your paint technical advisor. He will give you all the tricks.

    A profesional blaster is worth hiring. The machinery needed for a proper job is expensive.
     

  5. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    International is a good system. I use it because the technical adviser is on site in the shipyard.

    Many other good paint systems around. Choose the one with on site technical advice in your region.
     
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