Fiberglassing Plywood for Impact and Stiffness

Discussion in 'Fiberglass and Composite Boat Building' started by Ed3, Mar 2, 2008.

  1. Ed3
    Joined: Mar 2007
    Posts: 5
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: northeast

    Ed3 Junior Member

    Just looking for a little clarification on the utilization of fiberglass and it's application here.

    In looking at the Gougeon Brothers data on impact testing and the location of reinforcing fabrics in wood/composite construction, their conclusion points out that the best location for fabrics is toward the backside of a panel (one application being on the interior of a hull skin). Does this suggest the following would be true.?

    If a 2' x 2' piece of Okoume ( 6mm for example ) was bonded to a 2' x 2' x 3/4" frame, It would be easy to stomp on it with "X" amount of force and break through. If you were to cover only one side of the plywood (eg. 6oz. plain weave E-glass), Optimum impact resistance and stiffness would be achieved with the fiberglass applied to the underside of the plywood.

    Correct?

    Although simple "beam" test with a narrow strip of glassed plywood would verify my understanding, I am too lazy this morning, but energetic enough to give the most convoluted scenario for such a simple question.:D
     
  2. mongo75
    Joined: Aug 2007
    Posts: 262
    Likes: 6, Points: 0, Legacy Rep: 95
    Location: Orange County California

    mongo75 Senior Member

    I believe you are correct. I'm no physicist, but you could see how a well bonded piece of glass underneath will in effect "hold' or "catch' the wood trying to break through, whereas a piece on top would help some, but in the end it would basically be holding two broken pieces together like a hindge. However, you could always build up enough layers on the top to where it would be stronger than the one piece on the bottom, in essence makin the wood just a mold.
     
  3. Ed3
    Joined: Mar 2007
    Posts: 5
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: northeast

    Ed3 Junior Member

    Exactly!. Compression vs. tension. FG strongest in tension and stronger than the plywood.
     

  4. the1much
    Joined: Jul 2007
    Posts: 3,897
    Likes: 44, Points: 0, Legacy Rep: 696
    Location: maine

    the1much hippie dreams

    what are you trying to make impact res.?,,the glass or the ply?,,and doesnt that matter to where things should be (fg on top or bottom,,and isnt "impact" different then "standing" on something? and couldnt raise the impact res.,,and not raise the tension strength of the piece?,,,
     
Loading...
Similar Threads
  1. rracechase
    Replies:
    1
    Views:
    4,203
  2. HCB66
    Replies:
    9
    Views:
    1,074
  3. tessabeth
    Replies:
    13
    Views:
    1,180
  4. SamC
    Replies:
    28
    Views:
    2,366
  5. jdory
    Replies:
    29
    Views:
    3,063
  6. mojounwin
    Replies:
    8
    Views:
    4,694
  7. schlump
    Replies:
    11
    Views:
    2,338
  8. BlacK_Blade
    Replies:
    1
    Views:
    1,965
  9. BadGoblin
    Replies:
    13
    Views:
    2,899
  10. limitedreality
    Replies:
    2
    Views:
    3,151
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.