Materials - Graphite powder & epoxy vs solid

Discussion in 'Materials' started by ryanonthebeach, Sep 11, 2015.

  1. ryanonthebeach
    Joined: Mar 2007
    Posts: 74
    Likes: 5, Points: 8, Legacy Rep: 61
    Location: CA

    ryanonthebeach Junior Member

    Apologies if this is a bit off the forum topic.
    But didn't see one that covered materials

    I'm looking to cast a solid custom rigging parts, like dead-eyes


    If I use a mix of graphite powder or aluminum powder and epoxy in a mold would I attain the same or close to the same tensile/compression strength as solid aluminum?
     
  2. gonzo
    Joined: Aug 2002
    Posts: 13,378
    Likes: 329, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    No, not even close. The compression will be lower and the tension is way lower.
     
  3. ryanonthebeach
    Joined: Mar 2007
    Posts: 74
    Likes: 5, Points: 8, Legacy Rep: 61
    Location: CA

    ryanonthebeach Junior Member

    How about with milled carbon? or ceramics?
     
  4. gonzo
    Joined: Aug 2002
    Posts: 13,378
    Likes: 329, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    You could use aramid or carbon fiber, but the dimensions will have to be different. It will have to be engineered for the material.
     
  5. upchurchmr
    Joined: Feb 2011
    Posts: 2,820
    Likes: 85, Points: 48, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    Listen to Gonzo.

    You need long fibers, not short fibers (milled) or powder.

    You also need to forget about threads in a Gr epoxy laminate - unless you really don't need actual strength.

    If you ever try making a fitting like a deadeye, set up a test that will load it 2 - 3 x the load you need. Actually 5x would be better if you don't know about how structure and repeated loads act.

    There are guys who have made chain plate attachments by wrapping uni-directional graphite around a wire eye and spreading out the fibers on the side of the boat. Again, test it well before trying to use such a thing.

    In this case, metal good.
     
  6. TeddyDiver
    Joined: Dec 2007
    Posts: 2,541
    Likes: 109, Points: 73, Legacy Rep: 1650
    Location: Finland/Norway

    TeddyDiver Gollywobbler

    It's a deadeye folks, they were used to do them out of wood thou not softwood but not ebony either. Don't overcomlicate IMHO it's just there to prevent chafe and allow even loading..
     

  7. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 470, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I've cast epoxy parts with good success, but you do need to have a clue about what you're trying to do. I agree it doesn't have to be over engineered, but deadeyes are pretty highly loaded sometimes. The old wooden ones have been known to explode and personally, I can't offer any good reason for them, unless interested in the lightest weight, lanyard and lashing style of rig.

    What other parts are you going to cast and how highly loaded is the rig, they'll be hung on? If it's a low aspect gaffer, just use a heavy concentration of milled fibers, silica to control viscosity and the powder of the color you want. Pigment would be a better choice, as the resulting milled fibers and resin mix, will be stronger than with any powder. If it's a highly strung rig, you'll want to work out the loads, so you can make up a reasonable laminate schedule, which will likely include fabrics too.
     
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.