Wood or filler

Discussion in 'Fiberglass and Composite Boat Building' started by Tpoole86, Jun 30, 2013.

  1. Tpoole86
    Joined: Jun 2013
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    Tpoole86 New Member

    Hi all. I am in the process of replacing the floor of my boat. I basically know what to do but the marine ply is about an inch not wide enough on port and starboard. My question is can I use a filler such as a foam to fill it and then fibreglass over the top. Or do I have to put another piece of ply in the gap and fibreglass over that? Any help would be great cheers.
     
  2. rwatson
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    rwatson Senior Member

    Structurally, if the floor has to "land" at the edges, then foam may not be the best choice perhaps, especially if its only an inch..

    If not, then there are options you can go for.

    The other consideration is the 'look'. Is the ply going to be bright or painted ?

    Most boats aren't square sided, so is the gap all the way along, or just at the widest bit ?

    In some circumstances, its better to do a solid wood strip in the centre of the ply sheet to increase the width, as you only have one join to do instead of two.

    Pictures and structural info would be helpful.
     
  3. Tpoole86
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    Tpoole86 New Member

    Thanks for the quick reply. It varies between about half an inch to an inch (the gap gets smaller the further towards the bow) originally the floor was about 3 inches narrower on either side but it sat flush with the first chine. I have extended it to the second chine for a greater floor area. Adding an extra piece of ply will be really hard because of the non uniform shape of the hull sides. I will get pics tomorrow to give a better idea. And I was planning on flow coating the whole floor.
    Thanks again for the help much appreciated.
     
  4. PAR
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    PAR Yacht Designer/Builder

    For foam to be effective, it'll need a substantial laminate completely surrounding the foam. As you would think, foam, alone, just doesn't come close tot the strength and stiffness of the plywood, so the laminate needs to make up these differences. Unless you can make the foam filler, just as strong and stiff as the surrounding plywood, it's silly to consider it, simply because it'll shear (break) at the contact point. Fill the gap with solid laminate or a well bonded wooden filler strip.
     
  5. Tpoole86
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    Tpoole86 New Member

    Thanks for the info. Looks like I am not gonna take s shortcut there. Just didn't feel like standing at the planer for hours. I will put up some pics and keep you abreast of what's happening. Thanks again
     
  6. alan white
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    alan white Senior Member

    You only need to cut a piece of plywood that fills in the gap using a bandsaw or jigsaw. It can be done by first making the piece wider than needed so that it only gets cut to shape after being epoxied. Epoxy it directly onto the larger piece using thickened epoxy (peanut butter consistancy).
    Remember to make a series of tick marks on the big piece to allow you to cut the new edge accurately before pulling the big piece out.
    Epoxy alone won't be enough.
    Glass tape the underside before installing. Several layers will be needed to build up to between 1/16" and 1/8". Then carry on as if you hadn't screwed up.
     
  7. PAR
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    PAR Yacht Designer/Builder

    A scarf or Payson joint would be my approach.
     
  8. rwatson
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    rwatson Senior Member

    Do it the easy way of you can, as its being painted.

    Lay the narrrow sheet inside the boat.

    use a compass or block and pencil to draw a line around the edges, parallel with the side of the boat.

    Trim the edges so that if you push the sheet to either side, it matches the edges of the boat.

    Cut the ply sheet down the centre ,and push each side into place. Measure the gap in the middle, and cut another piece of ply or timber to fit in the parallel centre gap.

    Epoxy it in place with a wider backing sheet ( Payson Joint ). It will re-inforce the centre where most of the weight will occur, and leave you with nice neat edges to epoxy to the sides.
     
  9. alan white
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    alan white Senior Member

    A backer (Payson joint) means a lot of grinding to fit the sole so Rwatson's idea is particularly clever. The cleat being in the middle solves a lot of issues. Not a good idea if a cutout for seats, console, etc. will now not fit.
    A scarf is not easy to do for an ameteur, especially the skinny piece getting added on. Especially since it's curved! I suggest you try Rwatson's idea if it can be done and if not, Make a Payson joint or scarf where you can in a straight line near the side. this is assuming you've got some spare plywood. Not having the boat to look at, it's hard to say exactly how to do it. But mark the bigger piece for cutting as said before. That is actually a big advantage over any other way of fitting (including the way you mismeasured) which is one big plus you wouldn't ordinarily have.
     
  10. Tpoole86
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    Tpoole86 New Member

    So I have not put pics up sorry not very good with the computer. On the advice of a fibreglasser in town we pushed it all the way to one side and made that side fit perfectly. Then cut another piece of ply to fit the other side and biscuit joined them together and glassed over the whole thing. It turned out really well. Now just gotta make the seats, bait board and put a paint of coat on the new floor. I like making things maybe I should change careers
     
  11. alan white
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    alan white Senior Member

    Biscuits are good for lining things up but otherwise, they won't add any strength. If you're glassing the joint, you'll need a few layers especially on the underside. You really need to reinforce the joint and the best way to have done it would have been to add a piece of at least 1/2" plywood 6" wide underneath.
    Anyway, good luck with the project.
     
  12. bellearwood
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    bellearwood New Member


  13. PAR
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    PAR Yacht Designer/Builder

    Welcome to the forum Bellearwood.

    So how much bamboo do you carry and do you really think this an effective marketing strategy?

    Lastly, no typical laminate flooring wouldn't be a wise idea, for obvious reasons, to those familiar with marine requirements. You might want to study up on the markets you intend to spam, before suggesting a product that by it's own description, is quite ill suited to a cockpit sole covering.
     
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