Difficult Cutting Problem - What Tool Would You Use?

Discussion in 'Boatbuilding' started by CatBuilder, Nov 6, 2011.

  1. BATAAN
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    BATAAN Senior Member

    Looks like board in photo has downhaul too, which seems to make sense.
     
  2. Charly
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    Charly Senior Member

    So, if it has a downhaul, does the line run down into the trunk a ways, then turn and go out and back up to the deck? (I have zero experience with big boards)
     
  3. bntii
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    bntii Senior Member

    I would cut the skin with a Fein multitool on a line laid out on each side, then just cut out the core with a crosscut saw. You will need to grind out the tapers for the glass work to seal up the cutout.
     
  4. CatBuilder

    CatBuilder Previous Member

    Charly, our plans don't show a downhaul if he is using the same basic board (with a different area) on both boats. They only show an uphaul.

    BUT... I planned to add my own downhaul the same way as the uphaul is done.

    You can make a downhaul in 2 ways on the board/trunk design we have:

    1) Pot in another stainless eyebolt opposite the uphaul one on the plans and put a block on the deck right next to the trunk opening. Not sure if our boards are 100% flush when deployed, or if there is room to run a downhaul in this fashion.

    2) Pot in a downhaul eyebolt on the topmost edge of the board, so it is still accessible when the board is flush. Given that we have no slot for the uphaul line to live in when the board is completely flush, this may not work.

    Maybe we ought to ask Kurt which of the two is right.

    Could you ask and post? My "questions to Kurt" credits are running a little high right now. Can you ask him how to do the downhaul, which of the two methods?
     
  5. troy2000
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    troy2000 Senior Member

    Depending on how rounded the corners are, I'd drill small perpendicular pilot holes and use a larger bit or a hole saw for the corners. Then I'd cut both sides with a Skilsaw, rocking the blade down anD in with a plunge cut to start the cut.

    If the two cuts don't quite meet, they should be close enough to finish out nicely with that Sawzall of yours.

    How pretty a job that turns out is dependent on whether you get your original corner pilot holes perpendicular, have your Skilsaw blade at exactly 90 degrees, and can follow a line free-handing.
     
  6. Charly
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    Charly Senior Member

    LOL! OK.

    I hadn't really thought much about it, till now, but I had been assuming that the uphaul line came up , either through a hole in the top of the board, or through a groove cut into the trunk, next to the board, and was made fast with a jam cleat or just a cleat somewhere. My plans show a block mounted to the bottom part of the board, inside the cutout, (and that's all it shows) which must mean that one end is made fast somewhere, and the uphauling of the board is controlled with the standing part.

    Seems like a down haul ought to be springy , like a bungee or something, if the board needs to pop up.

    It would be nice to be able to control up and down both boards from the helm.... Is that how everybody else does it? Something tells me there is no "right or wrong" way to do this. Everybody's situation is probably a little different.
     
  7. PAR
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    PAR Yacht Designer/Builder

    Some times you have to be inventive when cutting things. A chain saw will make quick and fairly precise work of it, assuming you're well inside the lines and careful. The same is true of a reciprocating saw, but again you have to be careful and once you bend a blade, remove it and start again. Forcing a reciprocating saw, rather then letting the blade do it's job in it's own time, will guarantee a beveled cut. I wouldn't use a mutli tool on this, unless you're looking make a career out of it. Often a hand saw is a good choice, once you've drilled a few holes. "Connecting the dots" with a string saw works well, but again you need to be careful as it can get out of control easy too. All in all, I think I would try to "sneak up on it", first roughing it out with a chain or string saw, then fine tuning with whatever device of destruction you prefer.
     
  8. waikikin
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    waikikin Senior Member

    Right on!, a 9" grinder with a cutting disc to cut the straits from both sides & hole saw the corners from both sides, a hand saw will finish the small triangles of foam at the ends of the straits.
     
  9. hoytedow
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    hoytedow Old Woodbutcher

    I used a grinding wheel down the length of the cut to remove fiberglass, before making the deep cut, thus saving my saw blade.Clamp a board down the side of the grind area to protect the surface from any errant grind. Do both sides the same way and use the board as a guide to keep you on track. A batten would be adequate for this.
     
  10. PAR
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    PAR Yacht Designer/Builder

    You'll make a mountain of dust and bits with a grinder or you can use a very rough tooth saw, like a chain saw and have a relatively small amount of debris. Personally, I'd probably have used a reciprocating saw, with a course tooth count and I'd have doubled the blades, to make them stiffer and faster cutting too, not that a course blade is slow. Naturally, I'd have stayed within an 1/8" or so of the line and then finished up with a belt sander and other abrasive tools.

    The chain saw is a much over looked weapon and one that can afford a surprising amount of precision and usefulness. This could easy handle the cut depth, be kept straight and leave relatively little debris, compared to grinders, sanders and fine tooth stuff. "Sneak up and trim it in . . ." It's neater and you have the chance to do it quickly.
     
  11. CatBuilder

    CatBuilder Previous Member

    you know, I was thinking a chain saw would have been great too. Very straight cuts and plenty fast.

    I ended up using a combination of tools:

    1) Holes saws for the corners.
    2) Long drill bit to take hole saw pilot hole through to other side of board for alignment
    3) Circular saw to cut skins and maybe an inch into the foam
    4) Hand saw to cut remaining foam from the middle.

    Came out very nicely and of course I cut everything 1/8" short of the line and finished up with a belt sander.

    So funny about the chainsaw. Of course, my chain saw (used for years living in Maine on boats in the winter as my only source of heat) is in storage up north. Who would have thought I'd need a chainsaw in FL? ha ha ha :)
     
  12. gonzo
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    gonzo Senior Member

    Whatever you do, put on some tighty whities on before using power tools.
    A circular saw from both sides would be my choice(with clothes on)
     
  13. hoytedow
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    hoytedow Old Woodbutcher

  14. cthippo
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    cthippo Senior Member


  15. troy2000
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    troy2000 Senior Member

    We called those beam saws, back when I was a contractor. And they were pretty expensive. On the two or three occasions I figured it was worth it, I went down and rented one for a day.
     
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