Results 1 to 22 of 22

Thread: Galvanised nail heads throwing off filler.

  1. #1
    Join Date
    Apr 2008
    Location
    Penzance
    Posts
    1

    Question Galvanised nail heads throwing off filler.

    Hi all,

    my my client is concerned because some of his 4 galvanised nails are throwing off the polyester filler that was used to cover the nails. It seems to have expanded/exploded. He is concerned that he may have turned to boat into a battery over a couple of weeks by trickle charging with a bad contact. Do these pictures or this scenario ring any bells for anyone? 2 Doulas fir hull planking, 3 oak sheer strakes, in a saltwater harbour with a 240v lead aboard.

    many thanks in advance!

    3168A03E-75F1-4EAE-930A-D0EEF3EA9D5B.jpg0078612C-31E9-4F29-A94B-5EC262A24470.jpgC5EDF433-0EC4-4F24-AB4C-6BE6C985B552.jpg

  2. #2
    Join Date
    Mar 2009
    Location
    ibeeria
    Posts
    3,052

    Default Re: Galvanised nail heads throwing off filler.

    Welcome !

    Almost any galvanised material is difficult to recoat, there are specialised paint products for coating galvanised sheet, maybe use that as you would shellac over knots, isolating the head before filling.
    'C'est la vie' say the old folks it goes to show you never can tell

  3. #3
    Join Date
    Mar 2015
    Location
    Pukekohe, New Zealand
    Posts
    147

    Default Re: Galvanised nail heads throwing off filler.

    Looks like electrolysis to me.......not sure why it is happening as those nails should have been isolated.
    Has he filled the nail holes with a home made filler that is enabling air and water to get to the nail head?
    I would have preferred epoxy + glue powder.
    Turn the shore lead of. What is it used for?

  4. #4
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    14,670

    Default Re: Galvanised nail heads throwing off filler.

    Whats that boat got, one thick layer of latex paint?
    Punch the nails, grind the fir.
    Put thickened epoxy in the holes, prime and paint the boat better.
    bruce

  5. #5
    Join Date
    Jun 2000
    Location
    Madison Wisconsin
    Posts
    8,946

    Default Re: Galvanised nail heads throwing off filler.

    Polyester shrinks as it hardens, often making a spot where water can seep in. It also doesn't stick very well to either wood or metal, so the bond is likely pretty weak. Any filling on a wooden hull should be done with an epoxy resin mixture, not polyester.

  6. #6
    Join Date
    Nov 2004
    Location
    Port Townsend WA
    Posts
    11,454

    Default Re: Galvanised nail heads throwing off filler.

    Looks like sodium hydroxide crystals. This is often related to too much zinc under water. That white dust will eat up the wood! I suspect the trickle charger or a wire hanging in he water may be involved as well. You need a marine electrician to check this one out ASAP!
    Jay
    Last edited by Jay Greer; 07-10-2018 at 07:15 PM.

  7. #7
    Join Date
    Jul 2011
    Location
    Lindstrom, MN
    Posts
    2,040

    Default Re: Galvanised nail heads throwing off filler.

    I agree with all of the above, including "...not sure why it is happening as those nails should have been isolated.". When zinc corrodes, the oxide takes a lot more room than the metal, so it puffs up. Rust between steel plates can generate enough pressure to break bolts.

    The stray current seems unlikely to me, especially because the nails look like they are above the waterline. Stray currents can't travel through air.

    Polyester is somewhat permeable to water, and polyester filler probably more so. The quality of the galvanized coating may also be suspect. If it tended to flake as the nails were pounded in, look for "Made in China" on the box. I have had that experience all too often.

    The question is how to repair the coating, and the word client adds the phrase "without loosing my shirt". It is best to remove any rust, red or white. Then prime the metal heads with something like Pettit 6980 Rustloc or a reputable cold galvanizing paint using a small brush or cotton swab. As recommended above, fair with epoxy. Sand blasting wood can be a disaster, but hitting nail heads for a few seconds should be faster, neater, easier and more effective than grinding, and easier to fair in the end. A tiny sandblaster for nail heads can be made easily: https://youtu.be/zcjvT_pLkFY I might have to try it.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  8. #8
    Join Date
    Nov 2004
    Location
    Port Townsend WA
    Posts
    11,454

    Default Re: Galvanised nail heads throwing off filler.

    Wood will conduct current if it is wet enough, especially in salt water. Consider saturating the wood with clear penetrating epoxy resin first and then filling the damage with epoxy and micro balloons. This kind of glazing will be easy to remove if necsssary but it holds very well. Mix stiff enough to prevent sagging before it sets.
    I have seen boats with mounds of white crystals on the heads of keel boats and sorrounding wood. In one case, the zinc plate was ten feet away from the closest metal fitting. This is scary stuff as, the sodium hydroxide eats the wood in a manner simular to dry rot. Get an electrician to check it out!!! There may be a reverse current loop via the wood itself! The mere fact that this is happening is simular to the early stages of cancer! Get the cause fixed before major surgery is necessary!
    Jay
    Last edited by Jay Greer; 07-10-2018 at 07:15 PM.

  9. #9
    Join Date
    May 2002
    Location
    Deer Isle, Maine
    Posts
    1,463

    Default Re: Galvanised nail heads throwing off filler.

    This is a very informative article. http://www.marinesurvey.com/surveyguide/wood1.htm

  10. #10
    Join Date
    Feb 2000
    Location
    San Francisco Bay
    Posts
    11,542

    Default Re: Galvanised nail heads throwing off filler.

    I presume that the surrounding finish job is somebody's idea of a "workboat finish," no? I've seen roughsawn cedar board fences that were smoother than those topsides.

    If the described "4" galvanized nails" were not properly driven hot dipped square cut boat nails (with a strand of oakum under the head and dipped in pine tar before driving into a pre-drilled hole with the wide flat perpendicular to the grain) they will likely give trouble for as long as the boat lasts, and the boat is only going to last as long as the nails hold.



    http://store.tremontnail.com/cgi-bin...tems?mv_arg=32

    Stop the holes with epoxy and microballoon sanding filler, or, better yet, countersink and insert plugs properly.

    I, too, noted the reference to "a client." If you are doing this for money, you'd better wear a flack jacket when the customers start coming back!

    BTW, let your client know that screwing around with 220 VAC in a marina is a really good way to bring one's life to a premature conclusion.

  11. #11
    Join Date
    Apr 2010
    Location
    South Australia and Tasmania
    Posts
    14,540

    Default Re: Galvanised nail heads throwing off filler.

    A mains lead plus an automotive battery charger is a bad idea. Your client needs an isolating transformer to bring power aboard, and a decent marine battery charger. I'm no expert but I read this on the net.

  12. #12
    Join Date
    Oct 2008
    Location
    Walney, near Cumbria UK
    Posts
    39,635

    Default Re: Galvanised nail heads throwing off filler.

    Quote Originally Posted by Bob Cleek View Post
    I presume that the surrounding finish job is somebody's idea of a "workboat finish," no? I've seen roughsawn cedar board fences that were smoother than those topsides.

    If the described "4" galvanized nails" were not properly driven hot dipped square cut boat nails (with a strand of oakum under the head and dipped in pine tar before driving into a pre-drilled hole with the wide flat perpendicular to the grain) they will likely give trouble for as long as the boat lasts, and the boat is only going to last as long as the nails hold.



    http://store.tremontnail.com/cgi-bin...tems?mv_arg=32

    Stop the holes with epoxy and microballoon sanding filler, or, better yet, countersink and insert plugs properly.

    I, too, noted the reference to "a client." If you are doing this for money, you'd better wear a flack jacket when the customers start coming back!

    BTW, let your client know that screwing around with 220 VAC in a marina is a really good way to bring one's life to a premature conclusion.
    This. After cleaning the nail heads and painting with cold galvanizing zinc rich paint.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
    The weakness of the web: Anyone can post anything on the web.

  13. #13
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    14,670

    Default Re: Galvanised nail heads throwing off filler.

    I think it 's too late for that.
    How you gonna bore the hole with the nail in the way?

  14. #14
    Join Date
    Jan 2000
    Location
    Portland, Maine
    Posts
    16,217

    Default Re: Galvanised nail heads throwing off filler.

    Quote Originally Posted by Bob Cleek View Post

    BTW, let your client know that screwing around with 220 VAC in a marina is a really good way to bring one's life to a premature conclusion.
    I think in Cornwall all shore power is 220VAC. Aside from that -spot on.

  15. #15
    Join Date
    Oct 2008
    Location
    Walney, near Cumbria UK
    Posts
    39,635

    Default Re: Galvanised nail heads throwing off filler.

    Quote Originally Posted by wizbang 13 View Post
    I think it 's too late for that.
    How you gonna bore the hole with the nail in the way?
    The bores are round. Just need cleaning out. May be punch the nails down to ensure that they are tight. Then glue in wooden bungs.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
    The weakness of the web: Anyone can post anything on the web.

  16. #16
    Join Date
    Oct 2008
    Location
    Walney, near Cumbria UK
    Posts
    39,635

    Default Re: Galvanised nail heads throwing off filler.

    Quote Originally Posted by StevenBauer View Post
    I think in Cornwall all shore power is 220VAC. Aside from that -spot on.
    Actually 240V. Close but no coconut.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
    The weakness of the web: Anyone can post anything on the web.

  17. #17
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    14,670

    Default Re: Galvanised nail heads throwing off filler.

    Some kind of "barefoot " bitt Nick?

  18. #18
    Join Date
    Oct 2008
    Location
    Walney, near Cumbria UK
    Posts
    39,635

    Default Re: Galvanised nail heads throwing off filler.

    Quote Originally Posted by wizbang 13 View Post
    Some kind of "barefoot " bitt Nick?
    Looking at those images, I'd sacrifice a screwdriver to make a gouge of the correct radius and chip out the detritus.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
    The weakness of the web: Anyone can post anything on the web.

  19. #19
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    14,670

    Default Re: Galvanised nail heads throwing off filler.

    For hundreds nails?

  20. #20
    Join Date
    Feb 2000
    Location
    San Francisco Bay
    Posts
    11,542

    Default Re: Galvanised nail heads throwing off filler.

    Quote Originally Posted by wizbang 13 View Post
    I think it 's too late for that.
    How you gonna bore the hole with the nail in the way?
    Use a nail set to punch the nail head deep enough to hold the plug and allow for the point on a brad point bit, which will fetch up on the nail head or thereabouts when drilling the plug hole.

  21. #21
    Join Date
    Feb 2000
    Location
    San Francisco Bay
    Posts
    11,542

    Default Re: Galvanised nail heads throwing off filler.

    Quote Originally Posted by wizbang 13 View Post
    For hundreds nails?
    Well, that depends upon whether you want to do them all at once or a few at a time. In the later case, you can just do the ones that spit their stopping every so often as they become apparent. Eventually, they all will, I expect.

    None of this discussion about the cosmetic issues amounts to a hill of beans if the underlying electrical issue isn't identified and corrected, as Jay most accurately noted.

  22. #22
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    14,670

    Default Re: Galvanised nail heads throwing off filler.

    Bob,
    Does every boat not have an electrical issue?
    In a crowded "leaky" marina or isolated in a sweet water bay?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •