best acid wash / primer for mercruiser aluminum sterndrives?

Discussion in 'Sterndrives' started by Jeff, Jun 16, 2009.

  1. Jeff
    Joined: Jun 2001
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    Location: Great Lakes

    Jeff Moderator

    I'll be cleaning up the transom assemblies, etc. of a pair of mercruisers next week (zincs were missing or corroded 3/4 away, so transom assemblies now have some flaking/powered aluminum that needs to be sanded and repainted.)

    When I did this 10 years ago I used Interlux primewash yellow zinc chromate primer and then if I remember a purple Interlux aluminum primer (but I don't see that can for sale any longer) and then the black topcoat. That was a long time ago though (thankfully I guess!)

    I see Quicksilver sells a "Mercury Mercruiser Phantom Black Paint" but I'm not sure what this is -- am I correct it's just an enamal topcoat? I'm not seeing a QUicksilver primer/wash to go with their phantom black touchup kit.

    What's the best aluminum wash/primer/paint going now for refinishing mercruiser outdrives?
  2. mydauphin
    Joined: Apr 2007
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    Location: Florida

    mydauphin Senior Member

    I would sand aluminum down and spray with Zinc Chromate paint right away. Or used Alumaprep acid and Alondine (I forget exact spelling and still Zinc Chromate). Then I would paint epoxy paint or good outdrive paint.
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  3. Guest62110524

    Guest62110524 Previous Member

    use fast foaming hydrochloric THEN HOSE, WHILE STILL DAMP SPRAY ON or brush, spray from PLASTIC spray , alodyne, which will turn bronzy, it,ll stop oxidization, then paint with 250 microns dry of awlgrip or allcraft or altex devoe number one Alodine is used a lot in the aviation secter, it works, a very old trreatment, and provan, only on the yachts I build and treated this way ddi I have no problems By way there is no need to paint after this treatent, take as long as you wish
    I dug this up
    and the reason you do not apply through metal is that it will not TAKE
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  4. Jimbo1490
    Joined: Jun 2005
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    Location: Orlando, FL

    Jimbo1490 Senior Member

    I can report that the new kid on the block, Prekote, works very well and provides reliable adhesion. The manufacturer recommends it to be overcoated with a high-solids epoxy/chromate primer. This is a NON-TOXIC alternative to acids and chromic acid conversion (Alodine).

    Alodine is very toxic and contains heavy metal salts with fairly high 'bio-availability'. If you use it, you should protect yourself from exposure, but also capture all the run-off as it is a persistent groundwater pollutant.

  5. mydauphin
    Joined: Apr 2007
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    Location: Florida

    mydauphin Senior Member

    The stuff is nasty, imagine hosing a down 75 foot yacht with acid twice, then Alodine pouring out a sprayer... Gallons and Gallons... Then washing again.
    But it works real good against corrosion but it is really bad for environment.

    The Miami river has had many a boat yard since WWII and is so contaminated with Arsenic, Chromates that no one, I mean no one in their right mind will dive in it. Even with protective suits the county and city divers refuse to do it.

  6. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The acid prep is available at any auto paint supply. They use the same thing for truck boxes.
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