Dying Off Laminates at Transom?

Discussion in 'Boatbuilding' started by CatBuilder, Apr 13, 2011.

  1. CatBuilder

    CatBuilder Previous Member

    I'm curious about how to die off a cored laminate at the transom.

    Currently, I just have my transoms all over the place - they are runwild with no "bulkhead" installed back there, so it's easy to get in and out of the hull.

    My hull lamination schedule is as follows:

    34oz/1150g triax
    1" (25mm) of 6lb/100kg foam
    34oz/1150g triax

    That's what I have at the end of the boat at the transom, just run wild and untrimmed (they will need trimming for looks later).

    So how do I die off this laminate at the transom?

    Also, what about slight peels or never bonds at the edges? I have one or two tiny spots where the laminate is not quite completely on the foam. These spots are not even 1cm (1/2") in from the edge of the laminate and are very small. Do I need to worry about those spots, or will the layers of biaxial to be place on them, joining the keel and hull halves take care of that?
     
  2. hoytedow
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    hoytedow Wood Butcher

    How numerous are those 1/2" spots? How close together are they?
     
  3. CatBuilder

    CatBuilder Previous Member

    There are possibly 4 of them. They average 6" in length. They are fairly evenly distributed along the edge of 45' and not concentrated in any one place.
     
  4. hoytedow
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    hoytedow Wood Butcher

    Can you inject them with epoxy to fill them and thereby avoid a "crunchy" zone?
     
  5. CatBuilder

    CatBuilder Previous Member

    Yes, very easily. They're on the edge of the laminate. I could even take a stick and shove bog into them they are so easy to access. I could stuff them with dimes or pennies.

    What happened is a little bit of the edge of the glass peeled back off the foam during (or just after) lamination. I didn't catch it at the time.

    The area of the boat this happened on is where the two half-hulls come together at the keel. So, this is inside the keel, which will have many more layers of "things" including structural bog and biaxial over it.

    My main worry is that one of these little spots could somehow start a larger delamination years down the road.

    Not sure if I'm being too anal.
     
  6. hoytedow
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    hoytedow Wood Butcher

    You know I am not a professional, but I think if it is solidly filled, reducing the chance of expansion contraction or other such action, the chance of delamination will be greatly reduced. A bubble, on the other hand, could lead to nightmares. We need a professional opinion here. Just my 2 cents is not enough.
     
  7. bntii
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    bntii Senior Member

    I always grind out voids.
     
  8. hoytedow
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    hoytedow Wood Butcher

    That sounds good to me, followed by leveling the ground area before joining hull halves.
     
  9. CatBuilder

    CatBuilder Previous Member

    Ok, then what do you do?

    How do you glass the void properly after grinding it out?
     
  10. hoytedow
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    hoytedow Wood Butcher

    I build it back up with cloth and epoxy. having feathered the edge around the void.
     

    Attached Files:

  11. CatBuilder

    CatBuilder Previous Member


    I've never understood that.

    I have a single layer of 34oz (1150g) triaxial over the foam. How do I "feather" this?
     
  12. hoytedow
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    hoytedow Wood Butcher

    Bevel the edge by sanding, then lay in some more glass and sand that new glass level, like in the amended sketch.
     
  13. hoytedow
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    hoytedow Wood Butcher

    It will then be covered with more glass. Yes?
     
  14. CatBuilder

    CatBuilder Previous Member

    Yeah, but it won't be homogeneous.

    The patch will differ (structurally) from the original laminate because you'll have a double stack of +/- 45 cloth and no 0 deg cloth in the bevel because it will be sanded away during final finishing. (assuming 0 is up and the 45's are against the foam in the original laminate)

    The 0 deg fiber is very important. Thats what makes the boat strong in the most important direction of stress (longitudinally).

    You won't be left with the same type of laminate as the surrounding areas. :confused:

    Triaxial looks like this:

    [​IMG]
     

  15. hoytedow
    Joined: Sep 2009
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    hoytedow Wood Butcher

    In that case, if the grind out would be that significant structurally, then inject the voids to remove the voids and proceed as planned. That way you will not have compromised the original layer. However you do it, the air bubbles should be eliminated.
     
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