Alloy boats and dissimilar metals

Discussion in 'Outdoor Transport' started by distant stalker, Sep 16, 2017.

  1. distant stalker

    distant stalker dog chaser

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    I'm doing a bit of work on the boat that required more fixtures, wondering what others do to prevent dissimilar metals causing electrolysis i.e stainless bolts, I'm sure a few on here will have had a bit of experience with this stuff.
     
  2. quentin

    quentin Well-Known Member

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    I made plastic bushings for where S/S bolts went through the aluminium. For things like the transducer screws into the transducer bracket, I greased them, and removed and clean each year.
    Be sure not to use any copper or brass fittings directly against the aluminium.
     
  3. distant stalker

    distant stalker dog chaser

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    I'll be painting holes where can't get plastic washers in, hoping that's enough to prevent issues
     
  4. Fireflite

    Fireflite Well-Known Member

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    We used a Teflon Gel (barrier) that was applied with a paint brush that basically eliminated any galvanic issues.
    Might pay to see if something is available at a marine shop!?
    SS and aluminium are reasonably compatible.
    It's the alloying ingredients (alloy's) in the aluminium/SS that exacerbates issues.
     
  5. longrange308

    longrange308 Well-Known Member

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    The salts just as bad
     
  6. kiwijames

    kiwijames Lovin Facebook for hunters

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    [MENTION=5122]Fireflite[/MENTION]. I think we used a similar product when I was marine in the US. It was a product called Tef-gel. It is absolutely awesome. Lots of S/S fittings into aluminium were coated in this This stuff
     
  7. Dorkus

    Dorkus Well-Known Member

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    I just used a layer of silicon gell between the stainless washer and any alloy
     
  8. Markgibsonr25

    Markgibsonr25 Well-Known Member

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    copper cote?
     
  9. berg243

    berg243 Well-Known Member

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    tighten up screws and bolts to make sure everything fits then undo one bolt or screw at a time then cover them in neutral cure silicon and retighten,flush screws or bolts put another smear of silicon over them when first lot has set.
     
  10. Marty Henry

    Marty Henry Well-Known Member

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    Def not coppercote!
     
  11. distant stalker

    distant stalker dog chaser

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    Thanks for that I see jaycar are local stockists
     
  12. berg243

    berg243 Well-Known Member

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    depends if its his boat or someone he doesn't like.
     
  13. Gapped axe

    Gapped axe Well-Known Member

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    Berg243 has the berries
     
  14. scottrods

    scottrods Well-Known Member

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    NOOOOO

    don't add copper coat if you have aluminum alloy.
     
  15. Beaker

    Beaker Well-Known Member

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    Break a mercury thermometer in the bottom to. ...... :)

    No don't use anything with copper in it as a barrier agent.
     
  16. Marty Henry

    Marty Henry Well-Known Member

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    Mercury is total death, you can watch it eat the aluminum before your eyes. Have never forgotton watching it as a science project. Drop of mercury on a sheet of aluminum within a minute white "feathers" of aluminim oxide poke out of the mercury and just keep growing and growing. Teacher wipes the mercury off and where he wiped grows a forest of white plumes.
     
  17. Beaker

    Beaker Well-Known Member

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    It's a very impressive reaction for sure.
     
  18. yerimaginaryM8

    yerimaginaryM8 Well-Known Member

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    duralac is good for screws and rivets it's not cheap....DURALAC
     
  19. veitnamcam

    veitnamcam Almost literate.

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    Never!!!!

    copper and alloy is the devil !
     
  20. veitnamcam

    veitnamcam Almost literate.

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    Total isolation is always the best solution from a corrosion perspective but not always practical.
    next best is excluding h2O and O.
    Never use a copper type neversieze on alloy or near alloy components, it will cause the alloy to corrode.

    back in the day I used to use a green paste similar to shelac for bolting ss fasteners into cast aluminium and it was the ducks nuts....unfortunately I forget the brand at the mo.
     

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