Rudder filling material?

Discussion in 'Materials' started by D87, Jun 10, 2011.

  1. D87
    Joined: Jun 2011
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    Location: Australia

    D87 New Member

    Hi,
    I am restoring a 19 foot fiberglas Savage Nautilus and need to repair the existing fiberglass rudder.

    My rudder was in such a sorry state that I removed it from the boat and in the process of cleaning it up I ended up pulling it all apart with the intention of repair it from scratch. It was made of two fiberglass shells bonded together and filled with some kind of orange putty/filler substance. (see photos)

    http://img.photobucket.com/albums/v4...ingRudder2.jpg

    http://img.photobucket.com/albums/v4...ingRudder4.jpg

    The material was very heavy making the whole rudder weigh about 15 Kgs. I have separated the two halves and removed all of the orange material and now want to repair the damaged sections, glass the two halves together again and fill the intervening cavity with a similar material.

    My question is - Does anyone know what the orange filler substance might have been? Or is there anything I can use as an alternative? Whatever I use will need to be pourable and must set hard and be waterproof. I've considered using closed cell expanding urethane foam but I think it will be too lightweight for use as reinforcement in a rudder. Can someone help me with suggestions please?

    Thanks,
    D87
     
  2. daiquiri
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    daiquiri Engineering and Design

    You can, for example, fill it with epoxy. No way you'll ever again be able to pull it apart though. ;)
     
  3. D87
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    D87 New Member

    Thanks daiquiri,
    I have considered epoxy. It would work but it would take an awful lot to fill the rudder. This might be prove to be too expensive unless I could add something to the epoxy to bulk it out a fair bit.

    Cheers,
    D87.
     
  4. rberrey
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    rberrey Senior Member

    You can get heavy weight closed cell foam. I will use 4lb and 8lb in my dagger boards and rudder.
     
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The pink or orange stuff was probably just a filler. The reason the rudder was so heavy is it needs to sink positively (assuming a kickup rudder). You can install foam or anything else you want to fill the internal void, but the rudder still has to be heavy enough to sink it's submerged volume. I'd use lead, brass or bronze to make the weight and fill the rest of the void with foam. I'd use epoxy to join the halves too. No mat, just cloth and thickened epoxy, once everything is wetted out.

    Technically, you don't need the foam (again I'm making assumptions here), the two halves should be able to hold the glued in weight and the void could remain just a void. If you fill the void, then you don't have to worry about a nick permitting water to enter the blade. I'd use lead myself and I'd arrange the lead in a strip along the leading edge, which will also serve as an impact dispersal element that's easy to repair.
     
  6. Steve W
    Joined: Jul 2004
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    Location: Duluth, Minnesota

    Steve W Senior Member

    Ive filled rudders and keel blades with an epoxy/styrofoam bead mix,works well.
    Steve.
     
  7. D87
    Joined: Jun 2011
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    D87 New Member

    Hi Everyone,
    Thank for the interesting replies to my query.

    Par, I have replied also to you message in the Woodwork forum. I have some spare lead sheeting in my shed that I think will suffice. Thanks for the advice.

    rberrey,
    "You can get heavy weight closed cell foam."

    That is one of my problems. I'm having trouble getting it in Australia. There are a couple of dealers here but when I asked them if it is 4lb, 8lb, or whatever they don't know what I'm talking about. U.S. Composites has Closed Cell Urethane foam but they want $84 to ship it over here.

    SteveW,

    Thanks, I'll check out epoxy/styrofoam bead mix as you suggest.

    Cheers,
    D87
     
  8. Steve W
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    Steve W Senior Member

    D87, i didnt notice you were in Australia, the epoxy /Styrofoam mix is an idea i picked up from Kiwi multihull designer Malcolm Tennant as it was something used to fill rudders and daggerboards on his cat designs. The materials are easy to get,the styrofoam beads are what is used in a bean bag chair, or should be available in a craft or fabric store for next to nothing, with the epoxy you want to use the slowest hardener. Ive used this method for rudders on a Searunner 31 tri, a macgregor 36 cat and monohulls as well as several bulb keel struts.
    Steve.
    Steve.
     
  9. D87
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    D87 New Member

    Thanks for that info Steve, much obliged.

    Cheers,
    D87.
     
  10. rberrey
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    rberrey Senior Member

    US composites is where I bought mine,fiberglass supply is on the west coast and may have it as well , shipping may be cheeper from there.
     
  11. PAR
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    PAR Yacht Designer/Builder

    DuckTrap is probably the place you can find the materials and vendors you need D87. Log onto the site I recommend and search for DuckTrap.
     
  12. latman
    Joined: Mar 2010
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    latman Junior Member

    ATL composites on the Gold Coast used to have a 3 part foaming epoxy that would fill that void well. Other than that you could mix epoxy with Qcells or Fumed silica (cabosil /aerosil?) What resin are the skins made with ? I cannot see your photobucket pics sorry (says moved or deleted)
     

  13. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The rudder shell halves are polyester and look to be filled with a poly filler of some type. Again, don't try to make this thing too heavy, you want a neutral blade when immersed.
     
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