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  1. #11
    Join Date
    May 2001
    Location
    North Wales, sailing Aegean Sea or Menai Strait
    Posts
    21,852

    Default Re: Pitting on an iron keel

    Quote Originally Posted by sailaboutvic View Post
    I have a few round spots the size of old 50p , we plain to copper coat in oct , any suggestion ?
    Vyv your the man
    I repaired a gouge in my coppercoated keel caused by sailing over an underwater float made up of blocks of polystyrene wired together. This was at the beginning of the season, so by the time we lifted out it was quite rusty. I used an angle grinder taking the rust back to bright metal, then about four coats of west epoxy and a coppercoat repair kit, again four or five coats. That was a long time ago, maybe 10 years, and it is still good.
    Answers to some technical queries at new website http://coxeng.co.uk

  2. #12
    Join Date
    Aug 2001
    Location
    Lancashire
    Posts
    1,389

    Default Re: Pitting on an iron keel

    Quote Originally Posted by capnsensible View Post
    ... Last ten or so lifts, just scrubbed, let dry, wacked on a loada rust cure in whatever tin the local chandlers got, in whatever language (!) then undercoat and AF....
    Same here, though for more like twenty years on a succession of boats, in the course of which I've tried many "rust cures" Best I've found by a long way is this: https://www.promain.co.uk/rust-oleum...of-primer.html.

    I overcoat it with this: https://www.flagpaints.co.uk/product...etallic-primer which is superior to Primocon IMHO (compare the solids ratios)
    Last edited by JimC; 12-08-19 at 13:48.

  3. #13
    Join Date
    Oct 2014
    Location
    Keswick, Cumbria
    Posts
    1,843

    Default Re: Pitting on an iron keel

    Quote Originally Posted by JimC View Post
    Same here, though for more like twenty years on a succession of boats, in the course of which I've tried many "rust cures" Best I've found by a long way is this: https://www.promain.co.uk/rust-oleum...of-primer.html.

    I overcoat it with this: https://www.flagpaints.co.uk/product...etallic-primer which is superior to Primocon IMHO (compare the solids ratios)
    Ok, so looks like I have two choices, now keel has been pressurewashed.

    Use a flapdic on an angle grinder and grind out any rusted areas to shiny metal, then undercoat and af.

    Or just slap jims antirust stuff from his link on, and then undercoat and af.

    If I grind, any advantage to slapping on the antirust stuff as well before undercoating and af?

  4. #14
    Join Date
    Aug 2001
    Location
    Lancashire
    Posts
    1,389

    Default Re: Pitting on an iron keel

    Myself, I've used a flap disc, a rotary wire brush, and a random orbital sander at various times to remove loose rust and loose previous coatings. I end up with a keel that's a piebald mixture of adherent rust, bare metal, previous primer and previous antifouling. I apply the Rustoleum over the whole lot followed by the Flag primer (2 good coats) followed by the antifouling. After a couple of years of doing this I find further outbreaks of rust are usually only where I've bumped the keel.
    Last edited by JimC; 12-08-19 at 15:35.

  5. #15
    Join Date
    Jan 2004
    Location
    Med
    Posts
    6,023

    Default Re: Pitting on an iron keel

    Quote Originally Posted by vyv_cox View Post
    I repaired a gouge in my coppercoated keel caused by sailing over an underwater float made up of blocks of polystyrene wired together. This was at the beginning of the season, so by the time we lifted out it was quite rusty. I used an angle grinder taking the rust back to bright metal, then about four coats of west epoxy and a coppercoat repair kit, again four or five coats. That was a long time ago, maybe 10 years, and it is still good.
    Thank Vyv , any Epoxy or has it got to be west , may be a problem getting west in Sicily .
    Did you not treat it with any rust killer ? Or are they not wrote using ?
    Warning forumite dyslexia near by
    www.bluewatersailorcroatia.webs.com

  6. #16
    Join Date
    May 2001
    Location
    North Wales, sailing Aegean Sea or Menai Strait
    Posts
    21,852

    Default Re: Pitting on an iron keel

    Quote Originally Posted by sailaboutvic View Post
    Thank Vyv , any Epoxy or has it got to be west , may be a problem getting west in Sicily .
    Did you not treat it with any rust killer ? Or are they not wrote using ?
    Any decent epoxy should do. I think Coppercoat recommend another but that may also be difficult to source.

    I don't use any rust killers. Years ago some colleagues at work carried out scientific comparisons of all the rust killers on the market compared with normal preparation with no treatment. Sample plates in a salt spray cabinet and immersed on a raft in seawater. None of the treatments provided any longer life than no treatment.
    Answers to some technical queries at new website http://coxeng.co.uk

  7. #17
    Join Date
    Aug 2001
    Location
    Lancashire
    Posts
    1,389

    Default Re: Pitting on an iron keel

    Can you recall whether the tests included the Rustoleum primer I referenced in Post 12 Vyv? I ask because I've found it unmistakeably superior to Vactan, Fertan, Hammerite, Kurust etc. All these have allowed the rust to reappear through the subsequent coats of primer and a/f, which has only rarely been the case with the Rustoleum.

  8. #18
    Join Date
    May 2001
    Location
    North Wales, sailing Aegean Sea or Menai Strait
    Posts
    21,852

    Default Re: Pitting on an iron keel

    Quote Originally Posted by JimC View Post
    Can you recall whether the tests included the Rustoleum primer I referenced in Post 12 Vyv? I ask because I've found it unmistakeably superior to Vactan, Fertan, Hammerite, Kurust etc. All these have allowed the rust to reappear through the subsequent coats of primer and a/f, which has only rarely been the case with the Rustoleum.
    Sorry, no, I did not do the work and do not know any of the products tested, only that none showed any benefits. The work was done for the tanker fleet, in which case it may be that they tested a wider range of products than we have access to. Also, it was a long time ago.
    Answers to some technical queries at new website http://coxeng.co.uk

  9. #19
    Join Date
    Mar 2003
    Location
    falmouth
    Posts
    16,881

    Default Re: Pitting on an iron keel

    The basics are really staightforward. To rust, iron need water, oxygen and heat. You cant do anything about the latter so to prevent rust you need to cover a dry keel in an impervious coating. Doesnt even matter if its rusty before you coat as long as its completely dry.

    But therein lies the problem - how do you get all the moisture out of the pitts and crevices on what will be a pretty cheap and low quality iron casting. Indeed, can you get all the moisture out?

    The best you can hope for is to clear all loose debris on a warm dry day and then coat with your chosen moisture barrier. I once did the keels of my bilge keeler, one with VC tar epoxy and the other with chlorinated rubber. To my susprise, the latter lasted much better, but neither withstood my taking to the ground.

    The reality is that you wont win. Its just a question of how long between rcoats
    this post is a personal opinion, and you should not base your actions on it.

  10. #20
    Join Date
    Jun 2015
    Posts
    1,592

    Default Re: Pitting on an iron keel

    Just out of interest Vyv, would hot-dipping in Zinc when the keel is still hot from casting be a long (enough) term answer to justify the cost?

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