Skin material for skin on frame kayak

Discussion in 'Boat Design' started by Hultis, Aug 29, 2014.

  1. upchurchmr
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    upchurchmr Senior Member

    Ceconite comes in thickness appropriate for an aircraft.
    Boats typically get more beat up.
    I think the heaviest Ceconite is ~3.2 oz.
    Typical boat use weights starting at 9oz and go higher.
    Check out Kudzucraft.com
    Ceconite is typically a lot more expensive I believe.
    George Dyson is a source for a wide range of cloth.
     
  2. dinoa
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    dinoa Senior Member

    Layers of Dacron can also be laminated using heat and bond sheet giving a tough skin. Heat and bond can also be used to bond skin to frame.

    Dino
     
  3. upchurchmr
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    upchurchmr Senior Member

    Dinoa,

    Can you explain more?
    I don't know how you would use heat and "bond"? on a kayak?

    Bond with what?

    I can understand bonding dacron together on a flat table, but not on complex curvature.
     
  4. kerosene
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    kerosene Senior Member

    Is "heat and bond" name of a product?
     
  5. dinoa
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    dinoa Senior Member

    Take a sheet of heat and bond material along with the backing material and heat bond it to the existing skin. Remove backing and drape new layer over area to be covered. Bond using an iron set well below polyester melt point and at the lower region of its shrink temperature working from center out. At low setting iron will melt glue and do little shrinking. Increasing heat will also shrink fabric while keeping the glue liquid to to allow movement between layers. The resulting laminate is more resilient than the sum of the skins. Using elastomeric compounds to seal and finish the fabric also improves resiliency. Plastidip is cheap, has UV blockers, comes in colors as well as clear and retains its elasticity after ageing.

    Dino
     
  6. dinoa
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    dinoa Senior Member

  7. upchurchmr
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    upchurchmr Senior Member

    Don't you need to have the second layer under tension in order to get the most strength from the two layers?

    Do you know what kind of adhesive this is? I couldn't find it on the website.

    Have you done this with dacron?
     
  8. dinoa
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    dinoa Senior Member

    It's a hotmelt adhesive similar to that found on wood veneers.

    The outer fabric will pick up the tension loads in shear along the bonded area which is substantial. In areas where the fabric is highly stressed the second layer can overlap the first beyond its bond area to the frame itself if there is enough room though I haven't found this necessary.

    I have done this with 3.2oz Ceconite (dacron) with good results.

    Dino
     
  9. Tiny Turnip
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    Tiny Turnip Senior Member

  10. NoEyeDeer
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    NoEyeDeer Senior Member

    One thing I did find when I was toying with the idea of doing a SOF boat was raw Dacron from a local manufacturer in Australia. This is obviously no good for Sweden, but there are probably similar manufacturers in Europe. I can't see how there wouldn't be.

    The example I found is the stuff called Loomstate, which is raw Dacron straight off the mill, available in a 300 gsm that is not pre-shrunk. This seems like it would be good for SOF, although I haven't ordered any yet.

    http://bradmilloutdoor.com.au/products/artist-canvas-loomstate/
     
  11. dinoa
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    dinoa Senior Member

  12. Hultis
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    Hultis New Member

    upchurchmr: Where do you get $2.50 per yard dacron? Dyson sells it for $2.50 per foot. Then $60 shipping and $30-$50 customs. That means skin for one kayak would cost me three times as much as the actual skin cost... Finding something local is clearly the way to go.
     
  13. upchurchmr
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    upchurchmr Senior Member

    Hultis,

    I need to apologize. You are completely correct.

    I am sorry about misleading you. :eek:
     
  14. Petros
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    Petros Senior Member

    I am late to this conversation. I have built some 20 or more skin on frame hulls, I have used a varity of fabric, all work to one degree or another. You can use any tough fabric with low stretch, and a reasonably tight and smooth weave. But some work better than others. a little stretch is useful to keep puckers and wrinkles to a minimum, but low stretch fabric like polyester can also be used by adding some darts or tucks. 8 to 10 oz per sq yard is about min for good durability (though I have used lighter, but most go for much heavier).

    Cotton or linen duck or canvas makes a tough skin, but is prone to eventual rot, it lasts longer to keep it out of the weather and dampness when not using it (so it dries out). soak first coat all the way through with thinned oil based paint, and than put up to six or 7 coasts of oil based paint over it to fill the weave. You would expect to freshen the paint each season, and to reskin a boat in natural fiber every few years.

    Nylon or polyester is toughest, preferably uncoated and in raw from (before dying and finishing), but I have used remnants and surplus that were finished and it still worked well. Sew together smaller pieces with a zig-zag stitch in a double flat felled seam. once sealed you hardly notice the seam

    A smooth weave upholstery fabric in nylon or polyester would work, as long as the weave it tight enough to be able to seal it with paint or some other coatings.

    Stay away from fabric with rayon or acrlyic, it absorbs moisture and than rots very quickly. Nylon and polyester works the best, but cotton and linen have been used for many years and work well. I have also seen vinly upulstry fabric work well too, you do not have to seal it. But that is usually costly unless you can buy it surplus or find a left over roll in someones basement. You might go to shops where they make boat tops and canopies and see if they have any stained, faded or off color fabric they want to get rid of, they would sell it cheap.

    I have also used heavy plastic, the best is that white heat shrink plastic sheet they put on new boats when they deliver them, or to but boats in storage. I staple it on the top edge and use a heat gun to tighten it up, it is tough and works well but expect to replace it every season. it can can not be torn, but sharp edges will cut or puncture it.

    I have also considered using old boat covers, heavy drapery, and similar large pieces that get replaced. Just look around where you live, and consider where they use large amounts of heavy fabric, see if they will sell you about six yard of it. Or even better, have some surplus they want to get rid of.
     

  15. griff10
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    griff10 Junior Member

    I'm Bill Hamm, the method for covering a hull with aircraft Dacron then covering that with a single layer of glass/epoxy works just fine. Have built several and others including professional boat builders have also.

    Just because you haven't seen one done this way doesn't in any way mean it's a bad idea or can't be done, it just means you've not seen it.

    Bill H.
     
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