Composite structural pipework

Discussion in 'Materials' started by jtheriot, Jan 27, 2020.

  1. jtheriot
    Joined: May 2012
    Posts: 15
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: New Orleans

    jtheriot Junior Member

    8A116504-962B-47A1-99AB-AC1335C8E313.jpeg 15BDB565-7E83-4F8B-AABE-59BF2D0241ED.jpeg 36D4C79C-9458-493D-B513-BC4A121805C1.jpeg
    I am looking at the possibility of constructing a awning rack out of composite (glass, carbon , epoxy) vs aluminum. This structure is attached to the very back of the boat and is primarily used to stretch a heavy duty vinyl tarp to the cabin roof to provide shade. The use of preformed carbon or glass round and square tube seem to make this idea a possibility. The goal would be to have a very ridged piece with minimal flex. Diameter and wall thickness would have to be determined to be comparable to aluminum currently used. I know aluminum would be cheaper and much quicker to build but its more about the idea if it vs practicality. Below are some pictures of the basic idea of it.
  2. ondarvr
    Joined: Dec 2005
    Posts: 2,914
    Likes: 563, Points: 113, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    You can buy all the square tubing to assemble it, none of it is cheap though.

    You can make the sections yourself to about any dimensions you would like, square and/or rectangular are just a bit more difficult than round to build.
  3. roryact
    Joined: Jan 2018
    Posts: 4
    Likes: 0, Points: 1
    Location: New Zealand

    roryact New Member

    Suggest you'll get a better looking, safer and faster results looking at using flat laminated plates for the sides - it's just a whole lot less taping and bonding together than working with tubes. See below for a sketch, though you could cut out a whole lot more area than I have done for more visibility.
    You'd get the carbon weave displaying better on it than tube which always looks nice.
  4. JRD
    Joined: May 2010
    Posts: 232
    Likes: 20, Points: 18, Legacy Rep: 192
    Location: New Zealand

    JRD Senior Member

    Agree above is simple and quick.
    To laminate any frame straight and true you will need to build a jig first.
    Cutting tube ends to splice nicely into each other is slow and fiddly and you will end up with a miter join in each corner that will chafe your canvas. Alternative is to make some radiused corner transitions out of foam and laminate over them.

  5. jtheriot
    Joined: May 2012
    Posts: 15
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: New Orleans

    jtheriot Junior Member

    Thanks for the input. I know aluminum would be quick , easy and cost effective but this is a personal project and I really enjoy the versatility of composites. Next would be figuring out how much load my current setup is experiencing and determining material thickness to create a ridged piece. Again, thanks for the suggestions.
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.