mould change

Discussion in 'Fiberglass and Composite Boat Building' started by gages, Apr 25, 2013.

  1. gages
    Joined: Jun 2008
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    Location: australia

    gages Junior Member

    Just wondering if any one has done any in mould changes like adding new bits to a mould rather than manufacture a whole new mould ?

    I have an idea I want to do but dont want to have to make a whole new mould not at least until I see if it will work

    any suggestions or experience with adding onto a mould ?

    Thanks in advance
     
  2. tunnels

    tunnels Previous Member

    when you say changing a mould what exactly are you wanting to do ?? things like side windows Is just a plant shaped to what you want that can be stuck on with Double sided tap or screwed or bolted depending on the size and weight etc etc . Plants for out boards to change a transom can be sat in the back or corners and stuck in place ! The fixing are there till its gel coated and the first skin of glass is applied after that it will stay all by its self untill all the laminate has been laid up and around the plants . removeable plants come out with the hull after its finished and the securing hardware has been removed . The plans come away from the hull with a gental but firm blow with a rubber hammer usually!! to be saved to be reinstalled back on the hull again ready for the next hull !
    The thing about plants is they can be changed and so up dating or not used at all and back to the original shape :p
     
  3. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    I have used the same mold for hulls "relatively" different. What are you really talking about?. Can you be more specific about what you want to do?. How is the mold you want to use?
    There are many chances if you drive well the Body Plan.
     
  4. gages
    Joined: Jun 2008
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    Location: australia

    gages Junior Member

    I'm wanting to install a larger oval shaped hatch lid over the original smaller round hatch ,which means I need to make an insert of the shape I want and place this in the mould , I know I can insert this temporarily but can I cut and paste to make it a permanent ?
     
  5. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    I think it can be done but depends on the situation of the oval and the mold structure. With a figure I would get a better idea of what you want to do.
     
  6. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    You can change just about anything you want on a mold. The problem people typically run into is stress cracking around where a new section was added or changed, this has more to do with how they did it than anything else though.
     
  7. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Yes, you can do it easily. Make your new shape and affix it to the mold somehow, staying away from any silicone adhesives or silicone caulk. Fillet the new corners with modeling clay and wax it up, put on some pva and then laminate. Once done, you might have to do some filling and sanding to the new area on the product, depending on how good a finish you need and how carefully you work, but it is easily do-able to find out if your new ideas will work, while leaving a minimal/unnoticeable/no effect on the mold if your idea doesn't work and you have to remove the addition. The new addition only has to be able to take the stress of applying gelcoat and a layer of mat, after that you can work it like a regular mold.
     
  8. Cat Cruiser
    Joined: Aug 2013
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    Location: Texas

    Cat Cruiser Junior Member

    Greetings--Im new here. what you are talking about is really easy, you can do it with nylon inserts that you cut using carpenter saws most of the way and then grinders/sanders to fine finish. you could even use wood -but it dosent prevent sticking anything like nylon or other dense white plastics. A good plastics supply house usually has a drop piece box you can rummage thru and find what you need --$ by the pound. You can then attach the inserts onto the mold surface right where you want the hatch door recessed perimeter bead using ,
    . double stick tape if you dont want to mar the surface in any way. This way comes in handy for production molds where some parts want the hatch and some not-like what you have now. ( but to place the door insert in exactly the same place every timeyou would need a "skin fixture" locating it.
    . you can drill and screw the insert down , but you have drill holes in the toolface that must be clay'd over every time on production parts not having the door.
     
  9. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    Indeed nylon inserts, or even coated MDF inserts can be used. A temporary fix can be using sheet wax, which comes in 1x2ft sheets, in calibrated thicknesses. (self adhesive).
     

  10. Cat Cruiser
    Joined: Aug 2013
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    Location: Texas

    Cat Cruiser Junior Member

    Yes but the sheet wax gets real expensive real quick,it would be fine for one time mods. The OP should look in the yellow pages for a -Regal plastics- supply house. Teflon and any other similar works fine too. If the change is to be permanent, scew down--with countersunk screws and finish sand up to 400 grit would work fine.
     
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