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Anodised Aluminium- Can it be painted?

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  • 30 Dec 2015 18:31
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    Reply # 3732272 on 3714288
    Deleted user

    Zinc chromate etch primers have been used successfully for a long time as primers for aluminium. They were originally developd for use with aluminium aircraft parts by US civil and military aircraft.

    They are corrosion-resistant, and also highly toxic and possibly carcinogenic.

    Last modified: 30 Dec 2015 18:33 | Deleted user
  • 30 Dec 2015 16:56
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    Reply # 3732111 on 3714288
    Anonymous member

    i wouldn't recommend the use of zinc on aluminium. with -0.76V its potential is higher than that of aluminium (-1.66V) – could be a sort of a time bomb at spots where the covering paint goes damaged. in combination with salt it might slowly eat your mast…

    utnik
  • 30 Dec 2015 14:28
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    Reply # 3731933 on 3731641
    Anonymous member
    Mark Thomasson wrote:

    Is zinc on aluminium a good Ia good ideadea?

    I am pretty certain it was zinc primer …I'll try to check. To my knowledge , paint will only properly adhere to Aluminum with the right type of primer ….I BELIEVE it is zinc primer .


    Just checked . Yes , Zinc Chromate primer. It properly etches the Aluminum …so paint will stick.


    Last modified: 30 Dec 2015 14:30 | Anonymous member
  • 30 Dec 2015 11:01
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    Reply # 3731641 on 3714288
    Anonymous member

    Is zinc on aluminium a good Ia good ideadea?

    Last modified: 30 Dec 2015 11:02 | Anonymous member
  • 29 Dec 2015 09:11
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    Reply # 3723153 on 3722371
    Anonymous member
    Annie Hill wrote:Read all about it here - instructions from Awlgrip, which, by the by, also tells you how to prepare anodised alloy.
    Thanks for the link, very comprehensive.
  • 29 Dec 2015 02:39
    Quote
    Reply # 3722678 on 3714288
    Anonymous member

    I painted over mine.  First , I lightly sanded the mast to "break up" the Anodizing , then , sprayed 2 light coats of zinc primer , and then painted on 3 coated of Grand Banks Beige 1 part polyurethane. It looks GREAT. Hopefully it holds up well.
  • 28 Dec 2015 18:53
    Quote
    Reply # 3722371 on 3714288
    Anonymous member
    Read all about it here - instructions from Awlgrip, which, by the by, also tells you how to prepare anodised alloy.
  • 28 Dec 2015 10:19
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    Reply # 3721861 on 3721284
    Anonymous member
    Annie Hill wrote:In USA, it's the norm for 'quality' yachts to have polyurethane painted, aluminium masts.  They usually use Awlgrip.  Many moons ago, Wooden Boat magazine did a survey of the New England yards and asked them which boats took the least maintenance.  The answer was cold-moulded wooden boats with polyurethane painted masts (and some et ceteras, which are irrelevant to this discussion).  So it would appear that a properly prepared paint job on an alloy mast should last for a reasonable length of time.  Just be doubly sure that your other spars are well fendered.
    It would certainly be a cheaper method for me to paint the mast.  Also the supplier of bare ali is local to me.  Is it prudent to key the ali up by sanding prior to painting? 
  • 28 Dec 2015 05:03
    Quote
    Reply # 3721284 on 3714288
    Anonymous member
    In USA, it's the norm for 'quality' yachts to have polyurethane painted, aluminium masts.  They usually use Awlgrip.  Many moons ago, Wooden Boat magazine did a survey of the New England yards and asked them which boats took the least maintenance.  The answer was cold-moulded wooden boats with polyurethane painted masts (and some et ceteras, which are irrelevant to this discussion).  So it would appear that a properly prepared paint job on an alloy mast should last for a reasonable length of time.  Just be doubly sure that your other spars are well fendered.
  • 27 Dec 2015 19:30
    Quote
    Reply # 3720878 on 3714288
    Anonymous member

    Is it necessary to have the mast anodised?  Or is it sufficient to paint bare aluminium?  I use polyurethane paint (Garage floor Paint) for many tasks and have yet to find a surface it will not stick to.  What would be the difference in life sapn of a Painted/Unanodised, anodised mast?

    Thanks Mark
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