How to repair motor mount pads?

Discussion in 'Materials' started by Sprint 18.5, Oct 4, 2021.

  1. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    Here is a board.

    This is a clear, vertical grain board.

    The end shows the way that holds best; the side shows what doesn't work. The other side marked so-so will usually split the wood when bolted.

    In a 4x4; you may have pith or heart which is poor.

    1A62C9B2-16D9-4910-973C-A88FCE91C2FE.jpeg
     
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  2. Sprint 18.5
    Joined: Aug 2021
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    Location: Texas

    Sprint 18.5 Junior Member

    I have some 20 year old treatment 2x6’s and could go back and cut again correct for a tight or loose fit but thinking is it wasted energy and just use this stuff.
     

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  3. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    You are overthinking this. A plug with end grain will hold a lagscrew. For example a hammer head has a handle with end grain held only by a wedge. I have repaired many mounts with a dowel and never had a failure.
     
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  4. Sprint 18.5
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    Sprint 18.5 Junior Member

    So a loose fitting dowel with epoxy.
     
  5. gonzo
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    gonzo Senior Member

    Yes, loose fitting is the ticket. Otherwise there will be air entrapped in the hole.
     
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  6. Sprint 18.5
    Joined: Aug 2021
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    Sprint 18.5 Junior Member

    One small air pocket not purging enough.
    Tried grains both ways with very small cracks but with the grain it acted like a concrete fastener with expansion for a tighter plug fit.
     

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  7. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    You'll be fine. Lateral pull is where end grain fails so badly. You don't have lateral forces.

    Nice test.
     
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  8. Sprint 18.5
    Joined: Aug 2021
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    Location: Texas

    Sprint 18.5 Junior Member

    Way too many bubbles and must of stirred it too fast but I found a piece of pallet oak and cross grain it and will need more advice on installing and alignment here or new thread what ever recommended.
     

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    Last edited: Oct 8, 2021
  9. fallguy
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    fallguy Senior Member

    Keep it here. You know what to do now.
     
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  10. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    Me too. My douglas fir stringers I have glued in dowels and the lags held fine. I also filled holes with dowels and drilled new holes close by, and they held fine. They are pretty big and long and doubled up too. like 3 by 7 and run from mid of boat all the way aft. Doubled up where the engines sit. Another interesting dowel style repair technique to use are chopsticks or small thin shishkabob sticks, individually glued and pounded into holes till the hole is tightly filled. That has held on my splash rails using bronze screws where the holes were weakened. I did use a polyurethane glue PL Premium for that, not an epoxy. One of those holes I filled was about 1/2 inch wide in a mahogany plank. Some of those sticks are bamboo, works great to hold screws.
     
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