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Thread: Steel centerboard coating

  1. #1
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    Default Steel centerboard coating

    I am about to pull my centerboard which is a 150 steel shaped board. I'll need to take it down to bright as there is some rust and pitting. I'm pretty familIar with epoxy and wood/ glass, but not metal coatings. Straight epoxy e.g. West work? or should I be looking for speciality products? I'll have to do some filling and fairing. Final finish of course will be anti foul.
    Ben Fuller
    Ran Tan, Liten Kuhling, Tipsy, Tippy, Josef W., Merry Mouth, Imp, Macavity, Look Far, Flash and a quiver of other 'yaks.
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  2. #2
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    Default

    Ben, epoxy only sticks to metal like steel and iron, doesn't bond as it does with wood. So it's nearly the same as using paint IMO Almost anything like zinc chromate, Rust-Oleum or others converter, work well until the substrate metal is exposed. Interlux 2000e comes to mind because we all know not all paints bond well with epoxy.
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  3. #3
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    Default Re: Steel centerboard coating

    What is a "150 steel shaped board"?

  4. #4
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    Pounds, & foil shape

    Sent from my LG-M430 using Tapatalk
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  5. #5
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    Default Re: Steel centerboard coating

    Go down to the local marina/yard where the steel fishing boats reside and ask them what they used to paint their boats.

    Jeff

  6. #6
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    Default Re: Steel centerboard coating

    Ben, at the commercial shipyard that I was employed by a few years ago we used AkzoNobel / International Paints marine coatings with very good results on steel commercial fishing boats, both new-build and refit/repair. I have remained in contact with my local technical representative as they are very helpful. You can contact a tech rep at pcmarketing.americas@akzonobel.com and they will assist you in selecting the proper products and application methods to get the finish that you need. You might as well go directly to the source for advice...
    Hope for the best, but plan for the worst.

  7. #7
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    Default Re: Steel centerboard coating

    What Michael said.

    150 pounds.

    West epoxy is not a primer for steel. Primers need to prevent rust from undercutting the paint, so they need some corrosion inhibitors. One scratch and any primer without a corrosion inhibitor is going to fail.

    If I knew a good paint shop with wire arc spray zinc or aluminum or a hot dip galvanizer in the area I'd recommend that. For cold galvanizing paint, Sherwin Williams ZINC CLAD XI maybe. It might be less expensive to find a shop that uses it than buy the 4 gallon kit. So much for industrial coatings?

    Grit blast it to near white metal with a 2 mil tooth (a good shop will understand that to mean SSPC-SP10/NACE 2, 2 mil). POR-15 makes an easy to use zinc phosphate treatment that aids adhesion. I don't think that there is any magic to their paint though. Not bad, but perhaps over hyped. Pettit 6980 Rustlok is good. http://pettitpaint.com/media/4192/pe...tems-chart.pdf Note that they recommend prime, THEN fair, then topcoat. Fairing compound isn't a corrosion inhibiting primer, so the rust will creep under it.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  8. #8
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    Default Re: Steel centerboard coating

    I would use a coal tar epoxy, which is specifically for coating steel in a marine environment. Maybe that is what is being suggested above, I'm not familiar with those specific products.

  9. #9
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    Default Re: Steel centerboard coating

    we've had 2 steel centerboards and got them both galvanized once the fairing was done

    one was a trailer baby and the other(1970 model) was(still is) a fresh water girl that would get several weeks/year in salt water

    still no issues that we know of

    sw
    "we are the people, our parents warned us about" (jb)

    steve

  10. #10
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    Default Re: Steel centerboard coating

    ^ What he said. Hot dip is the very best way to go.
    It really is quite difficult to build an ugly wooden boat.

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  11. #11
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    Default Re: Steel centerboard coating

    I sailed a 14'6" dinghy around Cornwall for 7 years with a steel centreboard....sold it on for the same money as I bought her. She had a steel CB that was hot dipped, never a spot of rust on it having sailed 2-3 times a week year round, even sometimes dragging into the harbour sand as I landed.

  12. #12
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    Default Re: Steel centerboard coating

    I've had two boats with iron keels. I chip and wire brush the rust, coat with zinc primer, fill and paint.

  13. #13
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    Default Re: Steel centerboard coating

    I have used epoxy coal tar, but if there is already rust, that needs to go. Coal tar is now a banned substance in EU, so my last pot is still called coal tar, but is bitumen based. Its good if its on freshly blasted steel, otherwise good primers would be the way to go.
    Take Michael up on that link and use a proven system for best results. Double dipped hot galvanizing is probably a long term good investment.

  14. #14
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    Default Re: Steel centerboard coating

    Hi,

    How much surface area are we talking about and what sort of life span are you looking for ? My wife and I are finishing up building a 50ft steel boat (our second steel boat), so we have lots of first hand experience.

    My quick advice would be to get it hot dip galvanized if that is available locally and is within budget - it will do the prep and the coatings. However, it's not as common these days so second best is to get the metal sandblasted to white or near white and coat with a two part epoxy paint. Depending where you are I would just go with what your local industrial paint supplier carries - for example in our area it's PPG so we've used amerlock 2.

    It's interesting to note that the military and coast guard paint spec doesn't allow for zinc loaded paints under the waterline, I don't think it's a big deal for a centerboard , but just wanted to point out it's not critical.

    If you don't know much about blasting and need some background info my wife made up this little article on her website: http://mimijane.ca/interior-sandblas...ndblasting-101

    Have fun !
    Mark

  15. #15
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    Default Re: Steel centerboard coating

    On my iron keel I would chip and wire brush and immediately hit it with Rustoleum rusty metal primer. Wait a couple days and then bottom paint. Used to last three years reliably.

  16. #16
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    Default Re: Steel centerboard coating

    Thanks, locally in Maine I have several options for sandblasting if I drive an hour or two. Fortunately the board is only about 4' x 1' so fairly easy to move. I am not sure if I can find hot dipped galvanization. The coating advice looks good; from what I glean, a metal primer then I can fill and fair with epoxy before the antifoul. I will check with the sandblasters about a base coating. Most of the fishing boats around here are glass lobsterboats, but we do have one shipyard that does steel and I can swing in there and see if they either have a recommendation or can do a little job. Unfortunately the local steel fab shop is booked in for the next few months.
    Ben Fuller
    Ran Tan, Liten Kuhling, Tipsy, Tippy, Josef W., Merry Mouth, Imp, Macavity, Look Far, Flash and a quiver of other 'yaks.
    "Bound fast is boatless man."

  17. #17
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    Default Re: Steel centerboard coating

    Quote Originally Posted by Ben Fuller View Post
    Unfortunately the local steel fab shop is booked in for the next few months.
    They will be a great ally in finding hot dippers... often you can throw your job on with theirs to keep down transport costs...and often a 50 to the right person can get it done for just that.

  18. #18
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    Default Re: Steel centerboard coating

    Ben, the commercial lobster boat builders in your area create a lot of hardware that needs hot-dip galvanizing; they will know where to have it done at reasonable cost and fast turn-around. Have a conversation with the builders near you and ask where they get their galvanizing done. They may allow you to put your centreboard in with their next shipment, saving you shipping costs. Another source is the metal fab shops that build stuff for boatbuilders such as propeller cages, skeg extensions, flopper-stoppers, etc. - all their products need to be galvanized before installation. I wish you were closer - I could help you locally, but the closest facility in the NE USA I have found is in Taunton, MA.

    Oops - lupussonic got here ahead of me...
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  19. #19
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    Default Re: Steel centerboard coating

    Ben,

    Alumathane is a wonderful product, easy to apply, and has a good track record for rust prevention on less than perfectly prepared surfaces. It can be over-painted. It is available through progressive epoxy polymers inc603 435 7199 next door in NH. There are no hot dip galvanizers in the state, the nearest being in MA and they have, I believe, 500# minimums.

    Bruce

  20. #20
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    Default Re: Steel centerboard coating

    Quote Originally Posted by Ben Fuller View Post
    Thanks, locally in Maine I have several options for sandblasting if I drive an hour or two. Fortunately the board is only about 4' x 1' so fairly easy to move. I am not sure if I can find hot dipped galvanization. The coating advice looks good; from what I glean, a metal primer then I can fill and fair with epoxy before the antifoul. I will check with the sandblasters about a base coating. Most of the fishing boats around here are glass lobsterboats, but we do have one shipyard that does steel and I can swing in there and see if they either have a recommendation or can do a little job. Unfortunately the local steel fab shop is booked in for the next few months.
    https://galvanizeit.org/about-aga/ga...563&radius=500
    Looks like there are a few places in Mass. Wire arc spray may be an option closer to home.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  21. #21
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    Default Re: Steel centerboard coating

    Quote Originally Posted by MN Dave View Post
    https://galvanizeit.org/about-aga/ga...563&radius=500
    Looks like there are a few places in Mass. Wire arc spray may be an option closer to home.
    I find that arc spray is only a slightly better base for a primer.
    In salt water, my only choice would be hot dip, partly because the c/p gets dragged in sand and other abrasive bottoms and it also gets rattled a bit in the case.

  22. #22
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    Default Re: Steel centerboard coating

    Quote Originally Posted by willin woodworks View Post
    On my iron keel I would chip and wire brush and immediately hit it with Rustoleum rusty metal primer. Wait a couple days and then bottom paint. Used to last three years reliably.
    With respect, a cast iron keel is not a steel cb plate.
    It really is quite difficult to build an ugly wooden boat.

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  23. #23
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    Default Re: Steel centerboard coating

    subscribed to this one

  24. #24
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    Default Re: Steel centerboard coating

    Quote Originally Posted by Andrew2 View Post
    I find that arc spray is only a slightly better base for a primer.
    In salt water, my only choice would be hot dip, partly because the c/p gets dragged in sand and other abrasive bottoms and it also gets rattled a bit in the case.
    Yes, quality control and operator skill are very important with thermal spray. Hot dip forms a better bond. If done properly it can be a very good substitute for hot dip, but it is not the same. If done badly, it can be a disaster. This is a small piece, which limits the scale of the disaster.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

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