How to join Composite flat panels?

Discussion in 'Materials' started by Jaco, Oct 11, 2021.

  1. Jaco
    Joined: Sep 2021
    Posts: 4
    Likes: 0, Points: 1
    Location: South Africa

    Jaco New Member

    Good day,

    How do you join flat panels (sandwich panels) together when constructing a boat? I am considering making flat panels using vacuum bagging. However, how do you join these panels, making sure that the joints are mechanically strong? I am thinking of making modular panels, that can be joined together (on the mould), rather than one big panel, if that is possible.

    Is it possible to create a "tongue and groove" joint for composite panels, where one can make up an epoxy putty and bond the panels together?

    Also, can one use gelcoat, especially for panels to be fitted below the waterline, when making flat panels? Will gelcoat be susceptible to osmosis?

    Kind regards,
    J
     
  2. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,293
    Likes: 994, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Google duflex z-joint for one method. But that is for a series of panels joined together before being installed.
     
  3. fallguy
    Joined: Dec 2016
    Posts: 5,098
    Likes: 955, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    You can use epoxy and cabosil to edge bond panels, then they are typically taped with biaxial or some other specified tape and epoxy.

    You can also make reliefs or rebates like sheetrock so the seams are not proud of the panel for finishing.

    These panels were bonded on the edges, then inside while in the female jig/mould, then bulkheads added and then exterior tapes were done. Then the deck was done as a shoe and not rebated because didn't require much compound. Here is a picture of other deck work and beam integration, but this shows the seams well.

    1DE86478-8E79-4427-95EC-F11453A7AE2F.jpeg
     
  4. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,293
    Likes: 994, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    I guess the inside of the boat is a lot easier in terms of finish considerations, the "sheetrock" analogy certainly seems a neat solution for the outside.
     
  5. Jaco
    Joined: Sep 2021
    Posts: 4
    Likes: 0, Points: 1
    Location: South Africa

    Jaco New Member

    This looks great.

    I assume you do not have gelcoat on the outside of the panels?

    I searched for sheetrock, drywalling is not that common in South Africa. I notice the tapered ends on the sheetrock panels, which makes sense.

    Do you have a write-up of your build? Do you vacuum bag the panels, or do you do a hand-lay-up? What do you do at the open ends of the panels that are not joined - again epoxy and carbosil, or do you use tape as well?


     
  6. fallguy
    Joined: Dec 2016
    Posts: 5,098
    Likes: 955, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

  7. fallguy
    Joined: Dec 2016
    Posts: 5,098
    Likes: 955, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    You may 8AEE2A9C-57FF-45B6-8123-07788594C432.jpeg want to rethink gelcoat. For a number of reasons. This build method, for one. For another, modern 2 part paints, while toxic to breathe while flashing, are really very good and offer exceptional looking hulls. This is Epifanes Polyurethane. I had trouble with fisheyes; likey related to silicone mould release on paint trays from the paint supplier. This hull was rolled and tipped, but we did not tip the other hull and it looks better untipped.
     
  8. Scuff
    Joined: Nov 2016
    Posts: 154
    Likes: 20, Points: 18, Legacy Rep: 10
    Location: Richmond VA

    Scuff Senior Member

    Wow Fallguy that paint job looks great. So you just rolled without tipping and it turned out looking better than the hull above?
     

  9. fallguy
    Joined: Dec 2016
    Posts: 5,098
    Likes: 955, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    yes...weeist bit of non-notable orange peel
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.