Split mold for hull

Discussion in 'Fiberglass and Composite Boat Building' started by Sam III, Apr 22, 2008.

  1. Sam III
    Joined: Sep 2007
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    Location: League City, TX USA

    Sam III Junior Member

    Glad to give some background.

    I am taking a mold from a custom carbon fiber offshore 6.50 meter Mini Transat sailboat. We have finished the hull and deck for the prototype, finished fairing the deck and should be through with fairing the hull this week.

    Intent is to do take a female split hull mold and a single mold for the deck. We will be using balsa core in the mold for cost savings and weight savings.
     

    Attached Files:

  2. ratrace2
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    ratrace2 Senior Member

    SAMIII:
    OK you got the plug..........................If you got a plug then take the word "female" out of your description.....you just got a plug.
    Now, you have to make a mold...period, right. Right......
    Now, Problem is: what to make the parting plane from and how to attach it, right.
    Very simple, grass hopper.
     
  3. ratrace2
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    ratrace2 Senior Member

    Why do you worry about saving weight in a mold?????????????????????
     
  4. ratrace2
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    ratrace2 Senior Member

    Lay it on thick:

    two options:
    1, what I told you before: make a 3x4 extension of the mold and cut it in half with a sawzall.
    2. Chavant clay: build up a beam of clay along the longitudinal line of the hull and fair it with clay tools.....make it nice and smooth; about, 3" high, then lay some resin mixed with West 406 Colloidal Silica to form the initial "wall" section of your parting plane then matt it up to dimension.
    ________________________________
    So:
    step one:
    lay a beam of clay (chavant) from stem to stern 3x1.
    Spray mold release all over it.....
    Putty, then mat the Clay to make the flange...:)
     
  5. Herman
    Joined: Oct 2004
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    Herman Senior Member

    I once saw a guy cutting a plug with a circular saw, about 12mm (1/2") deep, then installing a piece of aluminium in the slot. A bit of modelling clay does the rest.

    Melamine covered particle board is suitable as well, as is polyester sheet. Attach with hotmelt glue, and again use modelling clay.
     
  6. wet feet
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    wet feet Senior Member

    Having seen the complete thread,am I the only one to wonder whether the designer of the custom carbon mini Transat has had any involvement in the operation?
     
  7. Sam III
    Joined: Sep 2007
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    Sam III Junior Member

    Yes the designer is involved in the build of the CF Mini and the future of the production mini boats that will come out of the molds. But he is not involved in the choice of materials and methodology of creating a parting board and the molds.

    I did put particle board coated in melamine on the center line as a parting board. Used hot glue and blocks to put it on and clay to create the fillet and fill any gaps.

    I will post results as we get it done.

    A couple of pictures of the results so far.

    Thanks to all that responded with suggestions.

    Sam
     

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  8. ratrace2
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    ratrace2 Senior Member

    WOW, where are your alignment pins???????????????????????????????
    You have to have something that will "key" the two parts together....
     
  9. Sam III
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    Sam III Junior Member

    Our plan is to use bolts with backer plates along the flanges.


    Sam
     
  10. ratrace2
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    ratrace2 Senior Member

    Alignment Key the Two parts: perfectly

    :) Listen, along this plane, (see Pic) place an alignment pin every 4 ft.
    What is an alignment pin. Well, in this case it would be a 2" x 3" rectanglar section of clay. Place the clay against the parting plane (white board). and then putty (remember the West Silica Putty)......and mat to dimension.
     

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  11. ratrace2
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    ratrace2 Senior Member

    Still need the pins............................
     
  12. ratrace2
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    ratrace2 Senior Member

    You don't get what I'm saying:
    Alignment pins have nothing to do with how you re-assemble the two mold halves, they--the pins--just make sure that the mold is re-assembled in "Perfect" alignment....................
     
  13. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    You can make alignment pins on a lathe very easily, two cones, male and female, they lock in perfectly to align the two mould halves, put them in at about 2 metre intervals, you stilll need to bolt the two halves together of course.
     
  14. ratrace2
    Joined: Dec 2007
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    ratrace2 Senior Member

    LL,
    good show, mate, wow that is a great idea. Unfortunalty, I don't think this "project" has that capacity available. LL, could you agree, just put a couple of "blocks" on this parting plane could achieve the "key" he needs, in a pinch.
     

  15. richard165
    Joined: Oct 2005
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    Location: New Zealand

    richard165 Junior Member

    Use table tennis balls cut in half and filled with filler for your alignment pins. Then hot glue to the parting board.
     
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