Building a stitch & glue boat in Fiji

Discussion in 'Boatbuilding' started by Saqa, Oct 20, 2013.

  1. Saqa
    Joined: Oct 2013
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    Location: Fiji

    Saqa Senior Member

    Looks like I will have enough offcut to do two layers on the inside seams and use the 200gsm plain weave tape for the frames and such or one layer on the seams and rest on the frames

    One thing I have heard mentioned a lot is chine logs, I think this be battens or such beveled to fit inside seams. Read a mention somewhere that they detract from the design of a monocoque shell. Since I have marine rated lumber now, would it pay to investigate logs vs 450 db tape?

    Are there any resources about crafting and using them?
     
  2. Saqa
    Joined: Oct 2013
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    Location: Fiji

    Saqa Senior Member

    Have finished sheathing the outer hull. Took just over 3L of epoxy
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  3. michael pierzga
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    michael pierzga Senior Member

    Yup...its coming along.

    For many projects i laminate the skin...waite till evening when the epoxy has gone firm, rubbery, then apply a layer of fairing compound.

    Saves time.

    The glass sheathing standing proud at your transom can be easily trimmed off with a razor knife before the epoxy has gone hard...in the rubbery stage.

    In future avoid 90 degree square cutouts...they a weak and impossible to cover with sheathing. Use a hole saw in the corners to create a large radius corner
     
  4. Saqa
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    Saqa Senior Member

    Yup thats the plan. Should be just right ina coupla hours. Only have talc so will be using that mixed with epoxy to glide on a coat with the squeege. I dont really want to build it on too thick, just enough to fill up the fabric so that when I cut back with wet sic paper I get a primer ready surface. Not sure if slight high and low spots will have much impact on hydrodynamics so would appreciate some thots on this. Would it be better to go for full fair?
     
  5. michael pierzga
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    michael pierzga Senior Member

    Thick, thin...tough call.

    I prefer thicker than thin and thinner than thick !

    Just thick enough so that you aren't cutting into fibers when you sand
     
  6. AnthonyW
    Joined: Oct 2012
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    AnthonyW Senior Member

    Fairing

    I am at the same stage with my current boat - also did one sheath in thick cloth due to lack of materials where I live. Have yet to fair it down though. I had planned to do this with slightly thickened epoxy and then sand. Are there better materials or process to use?
     
  7. michael pierzga
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    michael pierzga Senior Member

    Not really. If you are filling the weave mix up some runny thickened epoxy and spread it with a squeege. Small epoxy ridges will flatten out. .

    Sanding....or more accurately preparing cured epoxy on fiber is best dome with a wire brush not sandpaper. A rotary wheel or hand brush. The brush abrades the valleys in the fiber...sandpaper tries to flatten the fibers and fails to abraid the valleys

    Wire brush is a good tool.
     
  8. Saqa
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    Saqa Senior Member

    Anthony
    What are you using to thicken the epoxy? Our local brand has two different types of epoxy

    The stuff I used to laminate the glass is the regular clear stuff and the one I used on the seams, fillets and now for fairing is what the company labels as epoxy glue

    The rep for that brand came by to check out my build and he mentioned that the glue is epoxy with microfibres pre added and in the can it is some white stuff in suspension that he said needs to be stirred first. To make fillets I just thickened the glue further with talc (baby powder) figuring a mix of microfibres and talc should be ok for structural

    For the fairing I used talc again in that glue. Because of the microfibres I think its going to be an absolute pain to sand but its gotta be done. The regular epoxy can has a ratio on the back label to make fairing putty, 1:4 epoxy to microballoons

    Anyway, my first layer of fairing is now done. Looks like I wont need much more, the first bit of sanding will tell
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  9. waikikin
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    waikikin Senior Member

    Looks pretty cool Saqa, do those extensions of the running surface become like a step for boarding?
    Jeff.
     
  10. Saqa
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    Saqa Senior Member

    Yup boarding steps mate, I think the boat is too narrow for easy boarding from the sides when climbing in from the water
     
  11. PAR
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    PAR Yacht Designer/Builder

    You can and should sand through the biax stitching, which will save a ton of fairing later. This is simply a polyester thread used to hold the two uni-dia's together. These stitches are easily identified as the ones that run the length of the cloth. The actual 'glass fibers are at 45 degree angles to each other and under the stitching, which is why you can grind it off without harm. This said, it's easy to get carried away and ding the 'glass. With some care you can avoid this and spare yourself a lot of sanding.
     
  12. SamSam
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    SamSam Senior Member

    Don't you wonder about any health effects of using epoxy and sanding fiberglass in your living room/kitchen?
     
  13. Saqa
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    Saqa Senior Member

    Par I ended up filling the weave to the height of the stitching in most places with thickened epoxy. When I run the long board it should come up nice and plane in most areas as I can see its already really good by running a straight edge. But yeah will be knocking off the stitching by sanding down to the glass where the board falls

    Sam, I am not doing any sanding inside the house. Next task is to fit all the insides and glass the seams. Then she will go to the panel beaters where I will sand and fair then spary. Only health worry I can see with epoxy is developing a sensitivity and I have been using it for years and havent yet. Its a one off project so only exposure to the family is the few hours curing time. But if there is other health concerns that I might not be aware of then please do let me know!!!
     
  14. Saqa
    Joined: Oct 2013
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    Saqa Senior Member

    Marked out the flat bits that go on top of the side plates (gunnels?) in which I will fit the rod holders. It is a flat ribbon of 9mm ply that runs uniform width from the transom and when it reaches the curved area towards the bow it starts tapering exponentially and goes on to become the front deck or bow cap or whatever its called. Eight foot lengths joined together with butt plates underneath and another butt plate joining the two halves at the bow

    I am going to have a rub rail on the outy. 4.3m length cut from the 6m damanu plank and ripped into 15mm wide strips. One for each side of the boat. The plank is 25mm thick so that will be the height of the rubrails. Another pair of these strips will form the outside wall off the flat things so the 9mm ply will have additional 25mm added on the free edge 6" 200gsm plain tape to wrap this structure onto the boat sides. That is the project for when I wake
     

  15. michael pierzga
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    michael pierzga Senior Member

    The joint between the side panels and the deck..the sheer clamp...is a highly loaded structural component.

    Pay attention. A wrap of biax tape on this hull deck joint is needed.

    Many times its easiest to make the rub rail from a couple layer of flexible 6mm marine ply epoxed onto the topsides, set the deck on this in epoxy rail, let the rough plydeck extend past the plyrail, trim fair with a hand plane then biax tape over the deck rail joint, then add a timber or whatever strike, chafe rail outside.

    You will have more meat, the multi layer ply, to drive the timber strike rails fastening into and the sheer clamp will be robust.
     
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