What Can I Use ASIDE FOM EPOXY to Drill and Fill Holes in Balsa Deck?

Discussion in 'Materials' started by Chotu, Nov 17, 2020.

  1. Chotu
    Joined: Mar 2018
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    Chotu Junior Member

    I’m severely allergic to epoxy. Hospital visits and anaphylactic reaction on every exposure at this point.

    I have a an epoxy laminate deck with a balsa core and I need to mount some hardware by drilling and filling.

    What can I use apart from epoxy to seal the core?

    Mounting would be done like this.

  2. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    You can metal bush the core and use 5200 or 4200 if you want to get it apart someday. If you do it all same day; avoid the 5200 I'd say.

    Assuming your bolts are 1/4"; you would want 1/2" aluminum tube with 1/4" id. Drill at 5/8" for room for the glue.

    These come in a wide variety of sizes and deliver fast in typically a day or two.

    McMaster-Carr https://www.mcmaster.com/spacers/material~aluminum/for-screw-size~1-4/
  3. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    Fallguy, would it also be feasible to drill the holes oversize, and then simply use polyester resin with a suitable filler powder to fill the holes, before re-drilling them again for the bolts?
    I am thinking it should be ok, as the polyester will be in pure compression, and it has good compressive strength.

    Chotu, are you equally allergic to epoxy dust? If so, then maybe get somebody else to drill the holes for you, and to then sweep up and dispose of the dust?
  4. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    At that sinsitivity...
    Hire someone to do it for you!!
  5. TheThomas
    Joined: Nov 2020
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    Location: Annapolis

    TheThomas New Member

    You can add milled/ground fiberglass to a polester resin batch. I'd worry it would be brittle still, so before putting it in your boat, do a test batch and try stress cracking it through torque on a bolt. Other fillers don't even claim to add structural strength to polyester resin.
  6. missinginaction
    Joined: Aug 2007
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    missinginaction Senior Member

    Epoxy sensitivity is a tough one. I'd only add that you should use structural washers under nylocks with your backing plates. Most of the time the local hardware stores don't carry them, you need to order them or get them online. You may know this already. Structural washers are typically 1/8' thick for the 1/4 inch size and 1-1/4 inch in diameter.
  7. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    You could prep the hole and pay someone to spend half an hour filling the holes with epoxy. Your second choice would be vinylester resin and milled fibers.
    brendan gardam likes this.
  8. rangebowdrie
    Joined: Nov 2009
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    rangebowdrie Senior Member

    In the way that the pic is shown you gotta be careful how much you crank on the machine screws.
    In adding hardware to a cored deck it's possible to sometimes crush the top laminate into the core by over tightening the fasteners.
    The "fill" around the bolts needs sufficient area and compressive strength to eliminate that possibility.
    bajansailor likes this.

  9. Chotu
    Joined: Mar 2018
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    Location: Florida

    Chotu Junior Member

    I used vinylester and it worked great! Just like epoxy basically.
    bajansailor, hoytedow and BlueBell like this.
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