Any Ferrocement builders out there?

Discussion in 'Boatbuilding' started by cdubb, Mar 3, 2016.

  1. JSL
    Joined: Nov 2012
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    JSL Senior Member

    Yes, heard of waterglass but I like to stick with something I know - Xypex which has been in use and proven, in the concrete industry for 50+ years.
    Some shortcuts get you to new problems faster
  2. Maniek
    Joined: Dec 2007
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    Maniek Junior Member

    Here you right...Thanks...
  3. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    The most importnat part of a FC hull is the concrete mix. It needs to contain Pozzolan ( or Fly Ash) as an additive.

    I hear its relatively easy to get from indutrial sources.

    Any exterior coating becomes a lot less of an issue then. The Romans used it for aqueducts that have lasted a lot longer than any boat hulls.
  4. gonzo
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    gonzo Senior Member

    Fly ash can be gotten from free at any coal burning plant. They usually pay to get rid of it.
  5. makobuilders
    Joined: Feb 2009
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    makobuilders Member

    I think the first question that the OP needs to answer for himself is what is the intended purpose of the build? If it is to build a cruising boat, then it would be wise to heed all of the previous comments.

    However, if the OP wants to have fun and experiment with FC, then how about building yourself a 20ft daysailer. Minimal interior. Used or homebuilt mast and rigging. Or even easier would be a 20ft cuddy cabin powerboat with a small outboard. Minimal expense and maximum experience gained! Maybe he just wants to have fun.

    There's a guy on this Forum building a ten foot boat to sail the earth - that's an equally crazy idea and not my vision of a "family cruising boat for retirement" but perhaps he's doing it for the challenge.
  6. cdubb
    Joined: May 2012
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    Location: michigan

    cdubb Junior Member

    My intentions were to get a feel for the FC process and then build a smallish boat for coastal crusung to gauge the future. I'd also like to fit the smallish boat with a junk rig sail(s) just to try and get a feel for that pattern. Ultimately I would like to have a live-aboard cruiser. I actually bought a study plan for the 40' Norsk (which is catered to backyard FC construction) from Hartley in New Zeeland as kind of a end goal I guess. The Norsk fits what I want from a vessel quite well, she's got a deep draft but Im really in love it's appearance and layout. Really the whole thing is just trying to get a grasp on what I want and what can be done the simplest in regards construction.
  7. makobuilders
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    makobuilders Member

    Still since this is a new building technique for you and you're not entirely sold on it, it couldn't hurt to build yourself a small boat first. Perhaps even a 15ft skiff (heavy of course) with a little outboard. Just to become familiar with the price and the amount of man-hours involved to create so many square meters of hull, etc.
  8. JSL
    Joined: Nov 2012
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    JSL Senior Member

    The smallest FC boat I have seen & been aboard was a 28' sail. The hull was about 1/2" (13mm) thick. As mentioned, there are probably practical limits for minimum thickness so a small (16') boat may not be practical... or manageable... or sensible.
    FC fabrication has it's own traits so one idea is to make up a test panel with the correct armature and concrete (type 5 at 2:1 + pozzalin- that passes the slump test) using your correct tools (trowel, vibrator, etc) and then wait out the 28 day cure period (unless steam cured)
    The panel should be big enough to play with (2' x 8') and evaluate. It will give you a better appreciation of weight but you might be quite surprised at how flexible it is.
    If you still want to build that small boat, it can always used as an anchor for a permanent mooring or fill with dirt & plants as a planter.

  9. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    Smallest FC sailboat I know of is from Jay Benford. the 12' Keelboat. He also has a book on FC building there are used copies selling online.
    FC work depends on the quality of the plastering. This requires practice, so you either get a side job as a plasterer or hire the profesionals.
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