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Thread: Skinning a Kayak.

  1. #1
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    Default Skinning a Kayak.

    I'd promised last week to post a bit about the skinning of some non-traditional SOF kayaks that I'm building on upchurchmr (Marc's) thread about building one of Dave Gentry's Chuckanut 15's.

    The boats that we're building were slightly altered versions of Tom Yost's Sea Tour 15. Basically, we've got pine stringers and Okoume plywood frames. Here's an image of a skinned and un-skinned boat together:



    For much more detailed information on what I've got going on here, you can check out my blog posting if you're interested.

    For these boats, we opted to go with a relatively traditional method with a seam running up the stem and stern of the boat and across the deck. We used the 8oz Dacron (polyester) fabric from George Dyson at Dyson, Baidarka & Co. for our skinning material. Basting was done with white polyester and heavy stitching with artificial sinew. On some boats, you could skin differently - by having a piece of cloth for the bottom, stapled to the sheer clamp and a second piece of cloth stretched over the deck and also stapled to the sheer clamp. A thin rub strip at the sheer would cover the staples for a nice visual appearance. There's many ways to skin this cat - so to speak.

    Here's the basics of how we did things:

    Drape the boat with cloth, centering it in both directions.
    Pin the fabric in place at the keel and sheer, stretching lightly.



    Baste a "pocket" at bow and stern to keep fabric from moving.
    Roll boat upright and trim cloth proud of the centerline. Heat seal cloth with a small torch. (if you don't have a hot knife.)
    Stretch two pieces of 1/8" line bow to stern



    Fold the edge of the fabric over the nylon line and baste closely to the line. (Note the gap - to allow the sides to be pulled together!)



    Starting near the bow (or stern) take two curved needles and stitch the two halves together with overlapping diagonal stitches. Take the stitches as close to the nylon line as you can. The line distributes the force and helps avoid opening holes in the fabric.

    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  2. #2
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    Default Re: Skinning a Kayak.

    I should note that at the ends of the nylon line - about 1" back from the tip of the bow and stern - we stitched right through the nylon line to keep the fabric from sliding up the line. At the other end - inside the forward edge of the cockpit rim, we ended just 3/8" inside the rim with a stitch through the line.

    The center seams look like this:



    After doing the front and rear deck center seam, we cut the fabric at the bow and stern and sealed the edges. Folding the edge back upon itself to between the skin and the frame, we then cross-stitched the bow and stern closed. This left a relatively fragile exposed seam. So we made a "tape" with machine-sewn hems on both edges about 3/4" wide and whip stitched this to the bow and stern about 4" past our seam. We also incorporated grab loops into the tape to allow for lifting and tying down the boat. You can make out the loops in the first picture of Post #1. Here's the very bottom of the reinforcing strip:



    We then installed the cockpit rim and hatch rim using ratcheting straps to hold them down to the frame - and to flex them a bit. The rims had holes drilled through them to allow us to sew the fabric to them. First we pulled the fabric up the inside and basted around the rims. We then trimmed the fabric and sealed it about 1" past the basting line. We then basted another length of nylon line to the edge and sewed it securely to the rims. Like this:



    After the skins were all sewn in place, we took a steam iron and a meat thermometer to set the iron to 250F. We then steamed any wrinkles in the fabric out. We then re-set the iron's temperature to 340F and shrank the fabric slightly until it was taut on the frame.

    At this point, the skin is ready for "doping" with your choice of finish. Simple, but a bit time consuming as we were somewhat meticulous.
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  3. #3
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    Default Re: Skinning a Kayak.

    Canoez,

    Thanks for the pictures, you cleared up the big confusion for me by showing basting the deck seam with the cord leaving the cut off edge folded under. One question, how much width did you leave between the two cords - looks like 3/4" but did you leave less at the bow and stern?
    Gentry cautioned about pulling the 8oz cloth tight with the sinew - due to causing large open holes due to filaments moving easily. I can see where the cord would help with that issue.

    Do you have any pictures on the bow? Mine looks like a drunken surgeon did some work to show off. I also did not have a good idea about how to transition from the deck to the bow or stern.

    Do you have a picture of your first basting to the cockpit rim? I cannot imagine where the cord goes after you got the skin basted.

    Is there any way to see what the effect of shrinking looks like on the fabric or do you just get the tension up?

    Thanks,

    Marc

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    Default Re: Skinning a Kayak.

    Quote Originally Posted by upchurchmr View Post
    Canoez,

    Thanks for the pictures, you cleared up the big confusion for me by showing basting the deck seam with the cord leaving the cut off edge folded under. One question, how much width did you leave between the two cords - looks like 3/4" but did you leave less at the bow and stern?
    Gentry cautioned about pulling the 8oz cloth tight with the sinew - due to causing large open holes due to filaments moving easily. I can see where the cord would help with that issue.

    The gap varied from about 3/8" at the bow to about 5/8" in the center of the boat. We used hemostats to clamp the line at the appropriate spacing in the center and actually used brads to tack the line in place at the bow and stern. The cross-stitching with the sinew causes the gap to close nicely, but your needle needs to slide right past the line. You do have to keep up with it closing the seam as you go along or it is difficult to close later. If the cloth wasn't supported by the line, we would have had large holes opening up in the fabric. You can stretch a gap of maybe 1/4" closed before the gaps start to open up.

    Quote Originally Posted by upchurchmr View Post
    Do you have any pictures on the bow? Mine looks like a drunken surgeon did some work to show off. I also did not have a good idea about how to transition from
    the deck to the bow or stern.
    I didn't get a good picture of the transition from the rolled seam at the deck to the plain seam on the bow and stern, but here's a picture of the underside:



    Before this stitching was done, we cut the cloth about 1" proud of the stem and pulled both the basting line that made a "pocket" and the nails that held the end of the nylon line. The edges of the fabric at the bow were heat sealed and tucked between the skin and the stem form. We held them in place with safety pins. There was a 1/4" gap between these edges. We then took a piece of sinew with curved needles at each end and started up from the underneath of the rolled seam at the end of the deck seam (about 1" behind the bow itself). We simply carried the on with the cross stitch to the bow and over the stem until we reached the point where the cloth met.

    Quote Originally Posted by upchurchmr View Post
    Do you have a picture of your first basting to the cockpit rim? I cannot imagine where the cord goes after you got the skin basted.
    I do. It may not be clear tho:



    This piece of fabric is simply stitched to the rim. We then tucked the nylon line just underneath the stitch line and folded the fabric down, basting the line in place. (like the deck seam). Here's the line being basted in - you can see where the fold is happening 1/3 from the left edge of the picture:



    We then went back around - twice - stitching around the cord and through the holes. I still had some pulls here and am not completely happy with my method.

    Quote Originally Posted by upchurchmr View Post

    Is there any way to see what the effect of shrinking looks like on the fabric or do you just get the tension up?

    Thanks,

    Marc
    There's not much to see unless you overheat the fabric (it gets shiny and/or openings appear). If you apply too much tension, you might open up holes in the fabric. We kept tapping on the fabric to listen for the tension, rather than look for it. When we had good tension, the sound was drum-like. When we didn't it was a dull, "thwap". Be sure to calibrate your iron so you don't melt your fabric!
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  5. #5
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    Default Re: Skinning a Kayak.

    Canoez,

    Thanks for the details. I'm sure my second one will be much better with your help.

    Marc

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    Default Re: Skinning a Kayak.

    Nice thread, How about a definition of "basting".

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    Default Re: Skinning a Kayak.

    Good stuff!
    We must go too far in order to know how far to go. Yeah.

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    Default Re: Skinning a Kayak.

    Beautiful!.... Is that the only way to skin a kayak?

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    Default Re: Skinning a Kayak.

    Quote Originally Posted by Hwyl View Post
    Nice thread, How about a definition of "basting".
    Ok, also known as a "running stitch" - simply sewing up through two layers of fabric and back down through. Repeat. It's usually used to hem an edge or to temporarily hold things together.

    Looks like this (White on white is hard to see, but you can just make out the stitches here:



    Quote Originally Posted by Mrleft8 View Post
    Beautiful!.... Is that the only way to skin a kayak?
    Nope. Not at all. Just the way we chose to do things. Some people minimize the sewing by stapling the fabric closely with monel or stainless steel staples. Some people use a heat-activated adhesive tape (Usually used for aircraft) to bond the fabric to the frame. Some people omit the line that we used to reinforce the deck seam. Some don't cross-stitch the deck seam, they whip-stitch it. To some degree it depends on your choice of fabric, too. Yost uses stacked plywood frames to make his cockpit rim and avoids stitching at the rim. We didn't like the appearance of the rim or the large amount of wasted material that is required to make the three layers of the rim. As I said, there are many ways to approach this.
    Last edited by Canoez; 05-02-2012 at 08:24 AM.
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


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    Default Re: Skinning a Kayak.

    Ah..... So there's more than one way to skin a kayak!...

  11. #11
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    Default Re: Skinning a Kayak.

    And cats...
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


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    Default Re: Skinning a Kayak.

    Ok, folks - not quite done yet - some touch up to do on the paint work, but it needs to be "done" for the show, so here's the first viewing. Hasn't even been wet yet.

    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


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    Default Re: Skinning a Kayak.

    Looks good!

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    Default Re: Skinning a Kayak.

    I'm semi-pleased. I used a semi-gloss poly on the bare cloth (worked great). My student's boat is still just the semi-gloss and is translucent. We're going to use it like a huge Japanese "paper" lantern tonight as part of the display where I teach - an open house to let the public see all the student's work.

    My boat - I went on and had a tinted batch of the same semi-gloss made up. I started coating and knew the color build would be slow, but man. Terrible. The stuff also ran like a scared rabbit. So, I've got a few runs and curtains to clean up and probably two or three more coats of the colored stuff to apply. Meh. Next time I'm going to try an alkyd enamel.
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  15. #15
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    Default Re: Skinning a Kayak.

    Canoez,

    You left a little dangling bait for questions, so I thought I would bite.

    1. You said you didn't like the Yost stacked ply for a cockpit rim. How did you make the rim?
    2. What brand of poly did you use? How much tinting did you use? 2 Oz per gallon or what?
    3. I think you talked about waxing the frame before skinning. Why?
    4. On the translucent skinned boat, did you do something special to keep the poly from going all the way thru and wetting the frame? I got large and unpredictable blotching effect over the frame apparently due to the coating soaking straight thru - runs were the worst cuplrit. If I wanted to see the frame how could I make sure the coating went all the way thru the cloth.
    5. What design did you use?

    6. That looks great. I would like to see a picture of your lifting handles.

    Thanks,

    Marc

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    Default Re: Skinning a Kayak.

    Quote Originally Posted by upchurchmr View Post
    Canoez,

    You left a little dangling bait for questions, so I thought I would bite.

    1. You said you didn't like the Yost stacked ply for a cockpit rim. How did you make the rim?
    The coaming, hatch rim and cover were steamed cherry on this particular boat. The laminations are vertical in this particular case. I felt that the stacked plywood rims were not very attractive and were wasteful of material.

    Quote Originally Posted by upchurchmr View Post
    2. What brand of poly did you use? How much tinting did you use? 2 Oz per gallon or what?
    The polyurethane was a Minwax spar urethane - semi-gloss. I used un-tinted to seal the boat and then moved on to tinted. I had it done at the paint store, so I have no idea what ratio they used for the mix. In this case we started out with 18 units of yellow and wound up adding 4 of white to give it some "body". In hindsight, if I hadn't used the white, it would have been translucent yellow.

    Quote Originally Posted by upchurchmr View Post
    3. I think you talked about waxing the frame before skinning. Why?
    The waxing was to keep the finish from bonding to the frame. I waxed it and wiped the surface so there wasn't excess to cause issues with the finish such as fish-eyes.

    Quote Originally Posted by upchurchmr View Post
    4. On the translucent skinned boat, did you do something special to keep the poly from going all the way thru and wetting the frame? I got large and unpredictable blotching effect over the frame apparently due to the coating soaking straight thru - runs were the worst cuplrit. If I wanted to see the frame how could I make sure the coating went all the way thru the cloth.
    Well, if you want to totally saturate the cloth, I would think adding the appropriate thinner would help to reduce the viscosity and increase the penetration. However, that would be a double-edged sword, methinks. It would run everywhere - and if you think you had a problem with blotching and runs now... We didn't do anything particular to keep the poly from going all the way through and wetting the frame on the translucent boat. The first coat was simply very light and was intended just to seal the cloth - just enough to wet the cloth and nothing more. Subsequent coats were used to build the finish. I have some blotches on the yellow boat where the frame is prominent. It will take more finish to coat them effectively.

    Quote Originally Posted by upchurchmr View Post
    5. What design did you use?
    I started with Yost's Sea Tour 15. Width and general shape are the same, however I did raise the decks slightly and reduced the flare amidships. And as the stems are always a bit "custom" for Yost designs, OAL is actually 15'-6". I'm pleased with the results visually - I'll let you know about performance later.

    Quote Originally Posted by upchurchmr View Post
    6. That looks great. I would like to see a picture of your lifting handles.

    Thanks,

    Marc
    I'll get some detail shots tomorrow. The boat is over at the school where I teach as it is part of our "Open House" display today and tomorrow. Basically, it is a piece of polyester webbing that has been whip stitched to the fabric with close, tight stitches. This runs from the deck down the stems and a bit along the keel to get the points where the most abrasion will take place. A loop is left in this reinforcing webbing and is stitched together at the very tip of the bow to reinforce it. Works well and looks nice, I think.
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  17. #17
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    Default Re: Skinning a Kayak.

    Canoez,

    Thanks for the detail.
    Perhaps my next one will be worth posting some pictures.

    Marc

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    Default Re: Skinning a Kayak.

    Im at the skinning phase now...how much polyester did you use?This is my first time so I'm hoping not to screw it up..

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    Default Re: Skinning a Kayak.

    Marc,

    Here's a picture of the stern with the webbing. Basically, I continued the cross-stitching from where it ended on the deck and went down around the stem. For this part, however, there was not any nylon line basted into the edge. I just folded back the excess fabric with just enough gap so that the cross-stitching pulled the gap closed without "pulls" from the stitching. I then cut the length of black webbing (including the little "point" on the deck...) and heat-sealed the raw edges. Using some safety pins, I attached the webbing to the boat to hold it in place. Using the same thread I used to sew the deck closed, I whip stitched the edge of the webbing to the hull fabric, taking tiny stitches (so they wouldn't be seen) and sewed it to the boat. The webbing had a gather taken in it to form the loop that you see and I sewed across the width of the webbing at the very tip of the stem for reinforcement. (so lifting at the eye wouldn't tend to rip the webbing up the deck or down the stem) That what you were hoping for?

    Irish - I used the cloth at full width as received and the nearest even yard provided about a foot of fabric beyond either end. That was plenty to be able to pull the fabric taught end-to-end on the hull frame. It's one piece with the seam on the deck and at the stems.

    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  20. #20
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    Default Re: Skinning a Kayak.

    Quote Originally Posted by Canoez View Post
    My student's boat is still just the semi-gloss and is translucent. We're going to use it like a huge Japanese "paper" lantern tonight as part of the display where I teach - an open house to let the public see all the student's work.
    oh we need to see pics of that!!
    We must go too far in order to know how far to go. Yeah.

  21. #21
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    Default Re: Skinning a Kayak.

    Quote Originally Posted by Figment View Post
    oh we need to see pics of that!!
    I'll have to ask her - I think she got one with her phone.. I didn't get a photo as I was to busy on Saturday night. It wasn't as impressive as I'd hoped. I had two light fixtures with 60 watt fluorescent bulbs in them (Didn't want to scorch the boat!) but they really weren't bright enough to light all the way to the ends. I'll post pictures from the show a bit later tonight, I hope. Was kinda damp & dreary for the day - I guess we got nearly 3" of rain on Saturday.
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  22. #22
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    Default Re: Skinning a Kayak.

    Rigty-o. Here's the lit boat. More lumens were required.

    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  23. #23
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    Default Re: Skinning a Kayak.

    Quote Originally Posted by Canoez View Post
    Marc,

    Here's a picture of the stern with the webbing. Basically, I continued the cross-stitching from where it ended on the deck and went down around the stem. For this part, however, there was not any nylon line basted into the edge. I just folded back the excess fabric with just enough gap so that the cross-stitching pulled the gap closed without "pulls" from the stitching. I then cut the length of black webbing (including the little "point" on the deck...) and heat-sealed the raw edges. Using some safety pins, I attached the webbing to the boat to hold it in place. Using the same thread I used to sew the deck closed, I whip stitched the edge of the webbing to the hull fabric, taking tiny stitches (so they wouldn't be seen) and sewed it to the boat. The webbing had a gather taken in it to form the loop that you see and I sewed across the width of the webbing at the very tip of the stem for reinforcement. (so lifting at the eye wouldn't tend to rip the webbing up the deck or down the stem) That what you were hoping for?

    Irish - I used the cloth at full width as received and the nearest even yard provided about a foot of fabric beyond either end. That was plenty to be able to pull the fabric taught end-to-end on the hull frame. It's one piece with the seam on the deck and at the stems.

    Looks amazingly like a hamster eating broccoli....

  24. #24
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    Default Re: Skinning a Kayak.

    I think that's the foreman on the project. He looks nervous.

    Great thread Canoez, thanks.

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