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  1. #1
    Join Date
    Sep 2008
    Posts
    25

    Default Rusty Nail Heads

    I am getting ready to paint the outdoor trim on my 1840's house and have a question. Every nail head is showing through the old paint with rust. Is there anything I can do to prevent this from happening again when I paint it this time.

  2. #2
    Join Date
    Mar 2009
    Posts
    1,387

    Default Re: Rusty Nail Heads

    howdy remove all the nails and replace with exterior screws or stainless steel nails.

  3. #3
    Join Date
    Aug 2007
    Location
    Portland, Oregon, formerly of Chicago
    Posts
    1,770

    Default Re: Rusty Nail Heads

    Abrown,

    Trtaditionally, rusty screw headsare spot primed with an oil primer. Many painters prefer using aluminum paint as the spot primer.

    Some of the newer acylic paints on the market claim to stop minor rust. Behr's new Ultra exterior house paint is one. Its film is so dense that it blocks staining. It is also self-priming. You still have to hit bare wood twice, but you do not need a dedicated primer, merely the paint itself.

    Removing the existing nails would be an incredible amount of work and would probably result in damaging the smooth surface of the wood. Short of removing, the old nails could be driven in further and then the dimple patched with an exterior grade vinyl patching compound.

  4. #4
    Join Date
    Mar 2009
    Posts
    1,387

    Default Re: Rusty Nail Heads

    Howdy i was joking... unlse it is a teeny tiny house. opsee just could not help it.

  5. #5
    Join Date
    Aug 2011
    Location
    USA
    Posts
    2

    Default Re: Rusty Nail Heads

    Hello Abrown,

    Use white cement on old rusty nails and paint them with special paint that are available in the market. I think Ultra exterior is really better for that.
    Last edited by jenniferhoops; 08-04-2011 at 04:37 AM.

  6. #6
    Join Date
    Jun 2011
    Posts
    208

    Default Re: Rusty Nail Heads

    I'd also spot prime over the nail heads with an alkyd primer.

    If the wood were getting wet, the tops of the nail heads wouldn't necessarily rust. The fact that the tops of the nail heads are rusting means that those surfaces of the nails are exposed to moisture.

    Latex paints are permeable to H2O molecules (but not liquid water) and it's likely that the rusting is due to migration of H2O through the latex paint to the nail head.

    Oil based, alkyd and alkyd based polyurethanes aren't permeable to H20 molecules, so an alkyd film over the nail head should prevent further rusting.

    Post again if you want to know how latex paints can allow H2O molecules to pass through the paint film, but not liquid water.
    Last edited by Nestor; 08-04-2011 at 05:37 AM.

  7. #7
    Join Date
    Mar 2008
    Location
    nova scotia, canada
    Posts
    1,522

    Default Re: Rusty Nail Heads

    i completely agree with timothy miller on this. all that was available years ago for nails were bright and galvonized steel nails. for exterior use galvanized works but the coating slowly breaks down and you will eventually get rust streaks on siding.. also if the siding is cedar, the tannins in the wood will react with the product used to protect the nails and this will also cause nail bleeding.

    i do a fair amount of siding installs on high end homes. roughly half the homes we do get wood siding or fibre cement siding, both should only be installed using stainless steel. stainless will not rust and it wont react with cedar like galvonized will. we save galvonized nails for roof shingles and vinyl siding
    fire up the saw and make some dust

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