Steps: of Plug Mold

Discussion in 'Fiberglass and Composite Boat Building' started by LowelandSystem, Sep 18, 2016.

  1. LowelandSystem

    LowelandSystem Previous Member

    Hi good fellas,
    Please correct me if I am wrong to make plug mold:

    making a shape with wood or Blue foam> gelcoat and roving fiber> Curing and sanding> bondo filler> three coats> sanding and smoothing > marine paint top coat? Is this process right or I am missing something
     
  2. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    Wood or foam, make sure the foam is compatable with the resin you use. Or use a foam compatable resin (special order item)

    A couple of layers of CSM (no roving) as a base, depending on the size of the plug you may need more layers.

    Curing, light Sanding, filler, Bondo will work, but there are better products. As much filling and sanding as needed to get the shape you want.

    Paint can work, but it needs to be the correct type or it won't work. Better to use a polyester sanding primer like Duratec (it's made for this purpose), sand polish, wax.

    Now make the mold.

    The more time spent getting the plug right will save money and time now and later.
     
  3. LowelandSystem

    LowelandSystem Previous Member

    I live in a country, where duratec primer is not available. will epoxy paint will do. Or any easy alternative. Please battling with this Duratec alternative.
     
  4. AusShipwright
    Joined: Aug 2016
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    Likes: 5, Points: 8, Legacy Rep: 10
    Location: Australia

    AusShipwright Junior Member

    If you have gel coat you can add styrene wax and spray that onto the plug. Will need to make sure the plug is fair and also apply a neat coat of resin to help the gelcoat bond to the wood.

    Then sand the gel coat through the grits 320, 600, 800 etc. and polish. What release agents are you using?
     
  5. LowelandSystem

    LowelandSystem Previous Member

    Here in Bangladesh we have mold release wax, and silicon mold release spray..... but what is styrene based wax, I am afraid we dont have it here....:confused:
     
  6. AusShipwright
    Joined: Aug 2016
    Posts: 39
    Likes: 5, Points: 8, Legacy Rep: 10
    Location: Australia

    AusShipwright Junior Member

    Styrene wax enables the gel coat to cure and harden. Without it the gel coat will stay tacky. If you don't have access to it i would not proceed with the above method. It's hard to offer a solution without knowing what materials you have access to. I've only made molds using duratec and tooling gel.
     
  7. LowelandSystem

    LowelandSystem Previous Member

    will any kind of car body filler, like Duco (which is available in my country), which uses to fix dent cars, will it serve the same purpose?
     
  8. ondarvr
    Joined: Dec 2005
    Posts: 2,929
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    Location: Monroe WA

    ondarvr Senior Member

    As a filler and fairing putty....yes, but they tend to be soft and change shape when a part (mold) is made on them. Plus you need to cover it completely with a polyester top coat of some kind, otherwise it may bond to the part you build.
     
  9. LowelandSystem

    LowelandSystem Previous Member

    First the the car filler which hardens as cement, then fine sanding to smooth up, then three layers of waxing.Will that work???
     
  10. ondarvr
    Joined: Dec 2005
    Posts: 2,929
    Likes: 573, Points: 113, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    I have never use Duco body filler, but the online description indicates it's a normal body filler, which means soft and easy to sand, this results in a poor plug surface. And using only three coats of wax would probably mean the bond between the plug and part you build on it would be excellent.
     
  11. LowelandSystem

    LowelandSystem Previous Member

    guys,
    Bought this product:
    Universal 2K Putty / Filler
    83-4222

    Description
    A two-pack very fine putty that can be functioned as both heavy and light weight polyester putty. It offers exceptionally smooth application, superior drying time, and ease of sanding.

    Specification
    Activator: 2K polyester hardener [#21-42]
    Reducer: Universal thinner [#86-100]
    Mixing ratio: 100:3

    Will this work?:confused::confused:

    Link
     

  12. ondarvr
    Joined: Dec 2005
    Posts: 2,929
    Likes: 573, Points: 113, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Probably no different than the Duco product and most any other automotive body filler. It will work, it'll just be a bit soft and could change shape, and it needs to have a coat of something over it to protect it, or you may end up having large areas stick to the part being made.
     
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