laminating deck beams

Discussion in 'Wooden Boat Building and Restoration' started by robwilk37, Jan 9, 2013.

  1. robwilk37
    Joined: Nov 2010
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    Location: san diego

    robwilk37 Senior Member

    when cutting stock (VG DOUG FIR) for epoxy-lam deck beams, is the best practice, from a strength perspective, to run the saw cuts through the planer before glue-up or leave the relatively rough sawn surface for more tooth? the beams wont be visible in the end so i dont care about being able to see the glue lines, just trying to build the strongest way i can.

    TIA
     
  2. peter radclyffe
    Joined: Mar 2009
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    Location: europe

    peter radclyffe Senior Member

    its stronger if you dont plane
     
  3. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    It depends on what sort of sawcut you make and the type of glue and wood you're using. Titebond, resorcinal - the smoother the better. Epoxy is gap filling so it doesn't matter. Open wood pores are best, sawing and planing leaves them open compared to sanding which closes or clogs them.
     
  4. alan white
    Joined: Mar 2007
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    Location: maine

    alan white Senior Member

    Use a good quality sharp finish blade (10" 60-80 TOOTH) without planing and you'll save epoxy and get a good bond.
     
  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Yep, it depends on the adhesive. If epoxy, you can use a hatchet to make your strips. Most other adhesives will want clean cut tubules in the wood fibers and well fitted faying surfaces. If the surfaces are sanded, drag a sharp scraper over them, before gluing.
     

  6. ancient kayaker
    Joined: Aug 2006
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    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    The arch-tops of this fence were laminated from 3 layers of knotty pine from local lumber store. Surfaces were used as supplied - very smooth. PVA outdoor glue used (not Titebond). None of the six arches show any signs of delaminating yet although it's still early days, nonetheless it suggests a good PVA adhesive should be fine for a highly-stressed joint subjected to frequent moisture.

    Caveat: I read someplace that Titebond III loses 80% strength at 150 deg (C) so it may not be the best choice for a poorly ventilated dark-color structure in tropical areas. The other Titebond adhesives do better on the same test.
     
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