Fiberglass hull construction cost

Discussion in 'Multihulls' started by Stefano Dilena, May 23, 2021.

  1. Mr Efficiency
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    Mr Efficiency Senior Member

    Seems like a gargantuan task to me. The requirements of a mould go well beyond being the right 3D shape, I thought he might have meant a plug being cut using CAD program linked to routers, then a mould taken from that, but that isn't what he said.
  2. comfisherman
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    comfisherman Senior Member

    The little exposure I've had to it was a basis for csm to be faired and cleaned up manually. The cnc method of foam over cdx still seems to be the fastest.
  3. rxcomposite
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    rxcomposite Senior Member

    I checked with my data and we come close. Yours is cheaper.

    Assuming your shop rate is e 37.7 per hour and a productivity of 2.5 kg/hour, then your labor rate is e 15.1/hour ($18.4/hour). I use $20/hour here.

    For the catamaran with sandwich structures, I will have have to check my data and recalculate. Though I am using a weight based system, it is a little different. I use a ratio of hull weight to designed displacement.

    For polyester composites, I use 42 to 44% of displacement for hull weight of monohull. Trimaran is slightly heavier with 44 to 48% and cats has about 50 to 54%. It is the crossbeam in cats that makes it heavier. For the lower ratios. I use it for aluminum and epoxy cored composites. The higher ones are reserved for polyester because of lower modulus.
  4. oldmulti
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    oldmulti Senior Member

    fallguy likes this.
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    That is interesting, oldmulti, I note this: The printing material was acrylonitrile butadiene styrene (ABS)
    But after the printing, the mould was processed with routers to give the smooth surface. One wonders why it isn't done with routers from the beginning, working from the inside, rather than the outside with plug making, with some suitable material that is not too expensive, as the amount of material sacrificed could be substantial
  6. Rumars
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    Rumars Senior Member

    A quick look to the mentioned business site, gives following info: 3D Printed Resin Helps Deliver Advanced Manufacturing for the UK Combat Air Sector | Airtech Europe
    They expect this mold to last at least 250 cycles, mold material is a carbon doped PEI resin.

    3d printing molds can be cost effective because they cut down manual labour (sanding and polishing) but that is entirely location dependent.
  7. fallguy
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    fallguy Senior Member

    The routers Make sure round surfaces
  8. Stefano Dilena
    Joined: May 2021
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    Stefano Dilena Junior Member

    There is also this:
    Thermwood 3D prints a hull mold for a 51-foot long yacht - 3Dnatives

    As you can see, 3d printing moulds is already taking place, and has been demonstrated to be cost saving.
    Airtech Europe has a 12m 3d printer from LSAM and they offer additive manufacturing as a process. They can print a 1 piece mould that can be shipped in a 40' container!

    They also have experience making marine moulds for vacuum moulding and designed resins that can be used in autoclave ( potential use also for carbon hulls).
    I appreciate everyone's input, but I also understand the limitations of such discussions on an open forum.. I am already in contacts with some local boat builders so that we can better estimate the prices for our project.
    Thanks everyone.
  9. Dejay
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    Dejay Senior Newbie

    This is on a small scale but ideally you'd want to do it with a tool changer. Print a few layers then mill the print surface perfectly smooth and dimensional accurate: The future of desktop 3D printing - ASMBLâ„¢

    On the scale of these projects, switching to a milling / finishing tool while printing seems like good way to save labour.

    PS: Wow, printing in sections seems like simple and smart way to go about this!

  10. ondarvr
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    ondarvr Senior Member

    I worked on a 3D printed hull mold for a 36' cat a few years ago. It was done in two sections, it was done on one of the biggest printers around at the time.

    One problem was the structural integrity of each 18' section. They were thick and heavy, but needed better support than what the owners expected.

    I had to fly to Ohio to glass the entire part so it could be transported for cutting with a large CNC. Oak Ridge was where it was cut, then moved to Texas for building the parts.

    It was coated with Duratec primer because the bond to ABS is excellent.

    I never saw a finished part, or anything more from the owners. They planned to build high end electric cats for resorts and similar operations.
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