Faring clean steel

Discussion in 'Fiberglass and Composite Boat Building' started by Frosty, Jul 28, 2009.

  1. Frosty

    Frosty Previous Member

    With what would you fill and fare steel?

    I have 2 rudders that work fine but they are filled from nothing 4mm plate with a half inch bar welded to the back. ie quarter inch each side.

    They are simply wedge rudders for a power boat, the steel was unprepared--by any paint etc.

    I used polyester resin with talcum loaded onto the steel and a straight edge wiped it flat.

    Beautifull job but it came off, why? and what should i use and how to prepare.

    It will be covered in barnacles now!!
  2. Guest62110524

    Guest62110524 Previous Member

    this mornin I wrote a long reply your diesel prob, got bad feed, have no idea awhy
    dunno if you want MY help
    but here tis
    sand it best you can, brush on some phosphoric acid, let it dry
    hose off, coat with decent two pac poxy, a t least 4 coats brush, or 300 wft if you are spraying, then mix your bog
    best way is sandblast , but not practical should imagine
    be happy
  3. Frosty

    Frosty Previous Member

    Thanks for that Woosh, dont know if I have Phosphoric but I hear what you say. I will have some acid of some sorts somewhere.

    What engine prob did you write to?
  4. Guest62110524

    Guest62110524 Previous Member

    this stuff is specially for steel, it sorta goes sticky, available in paint stores
    oh your yanmar, , does it decelerate real slow?
    on some pumps there is a method of adjusting the decel rate, or the thing may be out of time, or the fuel may be shutting off in a dribble

    http://www.google.com.au/search?hl=...cd=1&q=treating steel phosphoric acid&spell=1
  5. Frosty

    Frosty Previous Member

    The rattle is when turning off, I see now what you mean. It is turning the engine off not as in slowing down.

    It is deep down in the engine, a serious rattle as the engine stops. I have changed a drive plate and it still made no difference.

    Obviously tortional vibration as the crank settles on a position between compressions.

    I will alter the thread.
  6. Guest62110524

    Guest62110524 Previous Member

    both or one, swap out the dampers, on the engine crank front, I member when I was with cummins, , an engine had a damaged damper, and wot broke, the crank of the twin cyl westinhouse air comp

  7. quicksail
    Joined: Jul 2001
    Posts: 58
    Likes: 1, Points: 0, Legacy Rep: 25
    Location: canada

    quicksail Junior Member

    One of the main reasons the fairing putty came off would be the use of polyester resin. Polyester's have zero secondary bonding properties (i.e. no glueing properties). The curing of polyester is entirely clemical and will only bond to itself. If you want to bond something to steel use a more glue like material such as epoxy or vinylester to a lesser degree. These two types of resins have secondary bonding properties which allow them to stick to various other surfaces like glue. That is why you should only use vinylester or epoxy for repair work as you cannot form proper secondary bonds to the existing material otherwise.

    For steel submersed in a marine environment I would use an epoxy putty. Although expensive you will get the best adhesion to the steel and it will be entirely watertight. I would then paint with a barrier coat of epoxy paint to seal the entire rudder "laminate" from water. If water gets in between the putty and steel no mater what it is I would think it would peel off. Well that is my lesson for today, I just learn this myself.

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