Earthen mold work boat

Discussion in 'Fiberglass and Composite Boat Building' started by rebar, Sep 25, 2023.

  1. rebar
    Joined: Sep 2008
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    rebar Junior Member

    Hey folks..

    I found a video on FB of Asians using soil and clay to form a mold for a good size work hull.. I'm still intrigued..

    Has anyone else seen such a method, and would it be dirt cheap? :D
     
  2. gonzo
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    gonzo Senior Member

    Dirt cheap, yes. The quality will reflect the price.
     
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  3. Rumars
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    Rumars Senior Member

    It depends on how good you are at working those materials. A male mold can be made from practically anything that can hold its. You could chisel one in marble if you like.
     
  4. gonzo
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    gonzo Senior Member

    I think he is talking about a mold made from a hole in the dirt.
     
  5. rebar
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    rebar Junior Member

    No, it's in the video I linked to
     
  6. Rumars
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    Rumars Senior Member

    That's also possible technically speaking, only you would have to be a very experienced and talented artist to pull it of, and those aren't stupid enough to try it.

    The people in the video use sand because labor is free and it's easier for them to do it this way. The boats are buildt by eye, each time the wooden topsides and frames are different, they can't use a female mold for the underwater part.

    The normal amateur working alone or with a small crew is better served by dry stripping such a mold and using some sort of filler over it to fill the seams and aid sanding. You can scrounge free wood for that, it doesn't have to be something of good quality. Even withies can be used, but again you have to know how to use the material.
    What they skip over in the video is all the pounding required to compact the sand until you can shape it. You can't just use an excavator to fill the frame.
     
    Last edited: Sep 26, 2023
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  7. rwatson
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    rwatson Senior Member

    Cheap dirt Moulds for Fibreglass would be a complete waste of time. A cheap, inaccurate concrete hull, maybe.
     
  8. jehardiman
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    jehardiman Senior Member

    Actually, it is quite common "out island" for small skiffs using a male plug mould and not female pit. Pile up the wet sand, smooth it down with some forms and battens, cover it with plastic, and start laying glass and roving to build up a solid hull, pop it off and install inwales. Not the prettiest or lightest but when you consider shipping costs to remote places, lower cube is preferred.
     
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  9. rwatson
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    rwatson Senior Member

    I didn't say it was uncommon (though I have never come across any) . I said it was "a complete waste of time".
    If you are going to spend that much money, building in the imperfections of hand made sand piles for such expensive hull material, rather than making a pretty accurate hull shape from wood or similar, defeats the purpose.
    Most 'glass hulls are powered by motor, and they will get squirrely at speed unless you get a pretty accurate shape..
     
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  10. rebar
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    rebar Junior Member

    I think the barrel boat guys might be interested in this because from the comments, most builders haven't heard of earthen molds.. I think you could lay up a flat bottom barge easily.. But I don't know what the price of a 55 gallon barrel of polyester resin costs, compared to blue barrels, but the advantages would be less draft and allot of under deck space..
     
  11. jehardiman
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    jehardiman Senior Member

    Note I said small skiffs...like canoe or small panga sized....where a thin skin and shape structurally suffices. This is not a method for large vessels. Even the moderate sized vessel in your video had frames and stringers to support the hull panels.
     
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  12. rebar
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    rebar Junior Member

    Barrel boat frames are usually around 8' x 20' so I'm just wondering if the cons outweigh the pro's when using a earthen mold this size. Yes, you'd have to construct a barge shaped wood frame similar to the video, no longer than 28'.
     
  13. philSweet
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    philSweet Senior Member

    If I recall correctly, there was an Ausie whose boat caught fire on a attempted record for 'round the south pole. By a stroke of luck, he was rescued off Antarctica. He went back to Oz and built a ferrocement boat on the beach in about three months and set off again. Made it the second time and went on to set several records in it in the southern ocean. It's a lot easier to float a boat out of a hole - just extend the hole out to the water and find a small dozer. His boat was about 60'. Casting keels on the beach is a very old practice.
     
    Last edited: Sep 27, 2023

  14. Howlandwoodworks
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    Howlandwoodworks Member

    I am amazed at the resourcefulness and tenacity of some people to pull them selves up.
     
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