Release agent and mold help

Discussion in 'Fiberglass and Composite Boat Building' started by Jacob J, May 18, 2010.

  1. Jacob J
    Joined: May 2010
    Posts: 3
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    Location: Denmark

    Jacob J New Member

    Hello

    I am new to boat building and yesterday I bought a boat (13 foot long). The boat has been build by laying fiberglass on the outside of an original boat of that type. My boat is in fact looking like an negative mold and I was wondering if it is possible to use the boat as a mold. It is very smooth on the inside and by my knowledge (or lack off) it seems like it could do the job.

    My first question is now, how do I prepare it for production?

    Second, if I would like to use mold release wax, which brand and type should I use and how much wax is used?

    Hope you can help me and sorry for my spelling errors, but my english is not that good.

    /Jacob from Denmark
     
  2. Obsession
    Joined: Jan 2010
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    Location: Chicago, IL, USA

    Obsession Junior Member

    Not to be negative, and I may misunderstand what you mean by "prepare it for production" and "built by laying fiberglass on... an original boat" but before you invest too much time, do you have the rights to produce this boat? Creating a mold based on an existing boat is known as splashing and definitely frowned upon. On the other hand, if it's a mold built on an original plug or a design you have the rights to produce and not stealing a designer's work, people will be much more inclined to help you. Sorry if I completely misread your post and my concerns are unwarranted.
     
  3. Jacob J
    Joined: May 2010
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    Location: Denmark

    Jacob J New Member

    I am not going to put this boat in production, just build a few for me and my friends and the design is not patented, because it is a homemade boat build by an old hunter in my town. The total weight of the boat is around 100 pounds, so that much rig isnt needed to handle it. The boat (or mold if we can call it that) looks like it is suitable for the job, but I need some infos on how to do it and so on.

    My I ask why it is frowned upon to "splash" a boat and make a mold?
     
  4. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    Due to stealing the work of a designer.

    The boat shape is property of either designer of producer of that boat.

    But anyhow, if there is no problem in using that shape, then I guess you deserve a decent answer.

    To prepare the inside of the mold (let's call your boat a mold, and not a boat), you should at least get rid of any cracks, holes and other defects that can prevent the new boats from being made.
    Use a compound and electric compounder to polish the inside to a high shine. Only now you are ready for cleaning and mold release.

    Cleaning can be done using a good household detergent. CIF is a brand that is available here, I guess they will have it in DK as well.

    Mold release: There are many products around. I suggest contacting some suppliers, and see what they have. One supplier that comes to my mind is HF Marine.

    After that you can apply a polyester gelcoat (put the mold on it's side, as the (heavy) styrene fumes can escape. Styrene fumes inhibit cure).

    Then laminate some boats, up to the desired thickness. And do some reinforcing.
     
  5. Jacob J
    Joined: May 2010
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    Location: Denmark

    Jacob J New Member

    Okay, thank you very much for the answers. How much wax is needed pr. square meter, if I deside to use that kind of release agent and how many times is needed for waxing?
     
  6. apex1

    apex1 Guest

    That depends much. Which products will you use, how shiny has the surface to be, and do you use release varnish on top of the wax?

    As Herman mentioned, contact a supplier or go through the datasheets of the different products most suppliers provide.
    Then ask the upcoming questions if there are any left.

    Regards
    Richard
     

  7. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    As Richard said, there are too many waxes, all with their specific properties (although they all will do the job).

    Rough estimate is that you will use one small can of wax for two or more boats. But usually you will get a datasheet, or the info is on the can.

    For example, Ferro FR8 or 16: I would recommend 8 applications of wax on a fresh mould. Each layer with a cure time of minimum 2 hours. This wax is applicated in the following way: apply with a cloth, as little wax as possible. (this is where you will lose much wax, and also why I will not give an estimate per m2). Let cure for 1-3 minutes. With a clean cloth, "break the surface". Now let cure for 15 minutes, and again with clean cloth, buff to a high gloss. Do approx 0,5 - 1 m2 at the time.

    Make sure you buff the surface really well (by hand) or you will see the gelcoat "run away" from the surface. This is the most common mistake.
     
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