Definitive Resource for Creating a Plug/Mold for Fiberglass Projects

Discussion in 'Fiberglass and Composite Boat Building' started by anamealreadyinu, Jul 12, 2016.

  1. anamealreadyinu
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    anamealreadyinu Junior Member

    I have an interest in learning how to make my own Plugs and then Molds of fiberglass projects. I've built a few boats using Fiberglass/Ply On Frame and Stitch-and-Glue methods using marine plywood.

    I've secured the rights to build a specific boat that comes in the stitch and glue method normally but by building a mold that follows the plans while eliminating the plywood core with fiberglass.

    I planned on assembling the boat from the plans using mdf, stitching, sanding and fairing until I have a perfect replica without the wood.

    Is there a definitive resource that can lay out the next steps to either turning this MDF replica into a multi-use mold or turning it into a plug and then a mold if that is what is required?

    I hope that is enough information to point me in the right direction. Thanks.
     
  2. gonzo
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    gonzo Senior Member

    You can use the lines of the boat, but the structure will need to be re-designed. If you haven't paid yet, your best approach is to buy a design made for fiberglass. A stitch and glue may need a several part mold; depending on the shape. As far as the plug, you need to build a boat and whatever parts will be made in fiberglass. The finish needs to be as good as the quality of the boat demands. Considering the competition on boat sales, a very good to excellent finish is necessary. In general, stitch and glue boats target amateur builders. They rarely have the fashionable lines and details that make a boat marketable.
     
  3. PAR
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    PAR Yacht Designer/Builder

    Some taped seam boats have very marketable lines, easily rivaling production boat shapes. The B&B powerboat offerings, are clearly palatable to a wide market and indistinguishable from production boats, if built with the same level of finish. there are several other designers that offer similar. They all don't have to look like a Bolger or Michalak, though many homebuilts are things only a mother could love.
     
  4. TANSL
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    TANSL Senior Member

    I think this gentleman does not need vague, generic phrases but concrete answers on how to build the plug and the mold of his boat.
    anamealreadyinu, if you give me your email I will send you pictures and the information, drawings, I use to create for a shipyard to build the same elements you need.
     
  5. anamealreadyinu
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    anamealreadyinu Junior Member

    Contact Info

    Thanks Tansl. Yes for this query I'm looking for specifics or a definitive reference to develop a list of materials and a step by step instruction/construction plan.

    email is anamealreadyinuse [at] gmail [dot] com

    Much of the printed material is very dated from the 90's or farther back. I'm struggling to find a book published in this millennium that references the latest materials and technique developed in the past decade or so.

    The boat is less than 14ft. and I plan initially on building them for a few friends and family. I secured the rights just in case it grew from there and I wanted to make sure I took care of the builder in an amicable fashion to maintain a long term relationship. I'm happy with the lines and the functionality and as I mentioned I'm not concerned with mass appeal, the boat serves a very specific purpose for a very specific area.

    Any information is welcome. Thanks.
     
  6. SukiSolo
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    SukiSolo Senior Member

    You might be well advised to look at FRP type construction, not just palin fibreglass layup. Using foam cores (or other light weight materials) will give a far superior product to a heavy glass laminate. There are some core materials complete with glass each side ready for laminating or vacuum bagging into a mould.

    This type of construction has become dominant in the UK for most dinghies as it gives the best consistency of stiffness and quality. Fishing and other recreational craft may require a slightly different approach especially if a lot of heavy beaching is anticipated.

    Don't forget that quite a few wooden boats have been built into a female mould.
     
  7. TANSL
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    TANSL Senior Member

  8. anamealreadyinu
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    anamealreadyinu Junior Member

    MOld

    Thanks TANSL, that look beautiful. I'll review and I'm sure have questions.

    I do like the vacuum bag approach @SukiSolo. I have access to some foam products and the vacuum approach appears to be the most economical.

    My problem with it is like any of the other methods is the lack of step-by-step documentation of how to start through to finish. Can you recommend any books on the foam/vacuum method?
     
  9. SukiSolo
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    SukiSolo Senior Member

    I'm sure you can find something out there if you search using the correct terms.
    I've seen even real pros having problems with certain processes, such is the way of things.

    This is a link to a UK supplier with a few tutorial/guides. Look for something similar your side of the Pond. Also do not expect things to be perfect first time, so allow for a scrap prototype - you'll find and hopefully solve any problems through it though.

    http://www.easycomposites.co.uk/#!/composites-tutorials
     
  10. PAR
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    PAR Yacht Designer/Builder

    It would be nice if there was a "Cliff's Notes" version for laminating and mold making, but I don't know of any. In reality, you read everything you can, incorporate this into your experience and continue reading about the new stuff, as it comes to importance to you. There's no sense in reading all there is on infusion techniques, if you'll never need them. Lastly, experience with the actual products and methods is where you'll learn the most. You can read all you want, but until you've had your hands covered in goo, you'll really don't know much.
     
  11. redreuben
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    redreuben redreuben

    Perhaps look for courses in FRP at a local technical college and see if you can beg or buy the course notes.
     
  12. redreuben
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    redreuben redreuben

    Reading your original post again my suggestion would be to use mdf in gloss Formica and build a female mould from that. If you looked after it you could probably get a half dozen parts, then if you were happy you could use one as a plug for a "proper" tooling quality mould.
     
  13. gonzo
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    gonzo Senior Member

    Saving on the mold is a mistake. Any flaw will get repeated on every boat. Also, it takes a lot of experience to be able to fair a reverse symmetrical mold.
     
  14. redreuben
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    redreuben redreuben

    Gonzo, you don't fair a Formica mould, if it's a stitch and glue design it's all flat panels. Cheap and quick for a prototype, do any fairing and alterations on your plug and then spend money on a tooling mould.
     

  15. gonzo
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    gonzo Senior Member

    I understood you suggested to make a female mold out of MDF.
     
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