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First post and and a question about skinning the boat


AeroE

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I've been reading everything I can find about skin on frame boats for the last week or 10 days.  I've been contemplating a new canoe to replace the 18.5 foot Alumicraft I own; my goal was something shorter and lighter and easier to transport, preferably in the bed of my pick up.

 

Photos of a new Cod Rib 12 set me off to research skin on frame boats.  I have been familiar with Platt Monfort's boats since the first one he built, but hadn't looked at the current "state of the art"(!) of SOF building going on, and so I'm interested in these kayaks.  The relatively simple assembly process meshes with my needs and my personality.

 

My question; has anyone skinned one of these kayaks with the 8 ounce or heavier fabric using the adhesives for the Stits or Randolph process?  I have experience recovering airplanes, I like the ability to shrink the fabric, and I'm confident in the seaworthiness of process.

 

I'm not wild about the heat activated adhesive film used by Monfort and others, but I have no first hand experience with that process so I might change my mind after a trial part.

 

I can't say I'm all that crazy about stitching the covering on either, although I suppose a relatively large whip or blanket stitch makes that go pretty fast.  I'm wondering whether the skin squirms around the frame since it appears to be restrained only at the coaming and the stitching around the stems.

 

I have a few more questions that I haven't seen addressed, but I'll hang onto those, this post is getting long.

 

 

Lee

 

 

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Never worked with any glues. Know nothing about them so can't comment on it.  Here is a link to my 3 part video on skinning a loose weave polyester.

 

http://kudzucraft.kudzupatch.com/video/skinning-polyester.php

 

I can say I have recently tried Heat N Bond tape and was impressed and no so impressed too. I would never trust a boat with JUST the tape. But I don't think it was intended to be all that holds the skin in place.  I used it on the ends to hold the fabric in place while I painted the boat then I covered the seam (bow and stern) with a brass rub strip.

 

But the tape held much better than I expected with a sideways pull. Very strong in that direction.  At the same time I could lift it upwards with ease.

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Lee,

I have a background and comfort level similar to yours with the Poly Fiber product line. The frame of My first Kayak is being assembled, and I would like to protect it with varnish. Then I think I'm going to cover it with the 8oz fabric.

Poly Fiber wants a wood frame fuselage to be varnished with their Epoxy Varnish (~$75) before appying fabric. I assume their glue solvents will dissolve all good oil based spar varnishes.

Therfore, I think I will glue the bottom fabric with a two part poly urethane coating for SOF Kayaks called "Cory's Goop".

http://shop.skinboats.com/2-Part-Urethane-Coating-for-Kayak-Skin-goop1.htm

My vision is to to apply the fabric to the bottom of the boat, wrap it up and around the Gunwales glueing it in place on three or four sides of the gunwale. I then will place one piece of fabric over the top, glueing it to the top and outside covered gunwale surface. I will then use Cory's Goop for sealing the fabric.

Looking for feedback.

Brooks

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Never worked with any glues. Know nothing about them so can't comment on it.  Here is a link to my 3 part video on skinning a loose weave polyester.

 

http://kudzucraft.kudzupatch.com/video/skinning-polyester.php

 

I can say I have recently tried Heat N Bond tape and was impressed and no so impressed too. I would never trust a boat with JUST the tape. But I don't think it was intended to be all that holds the skin in place.  I used it on the ends to hold the fabric in place while I painted the boat then I covered the seam (bow and stern) with a brass rub strip.

 

But the tape held much better than I expected with a sideways pull. Very strong in that direction.  At the same time I could lift it upwards with ease.

 

Jeff, adhesives and bond lines always exhibit the poorest strength under peeling loads, so we have to design to avoid that condition.

 

The best adhesive I've personally used and tested was a polyurethane made by PPG.  Although that was not the primary purpose of that material, it developed 50 pounds per inch in a climbing peel test.  The failure mode was mostly adhesion, but there was some adherend failure in the composite part.

 

 

I failed to complete my thoughts about stitching as I got in a rush.  Part of my objection is that the stitch line along the top of the boat looks a little too expedient.  Which I have no problems with when warranted, but that standing seam just doesn't sit right.  The seam along the stems clashes with my sensibilities of flow around an object in the water or the air.

 

Maybe I just need to get over it, or figure out how to sew a French seam.  Or give both a try.  I'll have a harder time reconciling use of a skin that won't shrink and stay that way, but I may have to try that, too.

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Each to his own and I don't try to stop anyone from trying something different. Not that I could if I wanted too!  But at the same time I only encourage and support methods I know and use. When you vary from that your are on your own, I will offer no support.

 

I looked at glued on skins and the only examples I saw looked bad. The seams stood out like a sore thumb. Maybe that was just a poor job but it was ugly enough I lost interest really fast. 

 

I settled on the methods I use for a several reason. My boats appeal to a broad spectrum of people but most are first time builders. The low cost, the lack of epoxy, lightweight and simplicity are the big draws. Almost anyone can sew on a skin and then shrink it. It works well and it's simple and cheap.

 

Many people come along and feel the need to 'improve'  construction methods. I have incorporated a couple of ideas from one builder that actually improved my designs. Most, to me, just add complications with little if any advantage. But I am always open to new ideas if they improve the design while staying true to the low cost and simple appeal of the boats.

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Jeff, adhesives and bond lines always exhibit the poorest strength under peeling loads, so we have to design to avoid that condition.

 

 

Just to be clear but I was only using it to temporary hold the fabric in place. Once the finish was applied I screwed a brass rub strip over the joint. It anchors the seam, hides the seam and protect the boats skin.  I have just gone back to using stainless staples. It's MUCH simpler and quicker.

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I've only skinned one kayak so far, used Jeff's plans/methods/instructions.  The stitching came out fine and once shrunk and painted ends up looking somewhat like a length of braided rope and IMO adds to the overall look.  The few times I've had the Curlew out as well as visitors to the boat building shop aka "our garage" has brought nothing but positive comments and interest in the construction methods used.  I'm a rookie at building SOF boats using this method, but would not hesitate at all in building another one...which reminds me, I need to build one for fishing.  :)

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I wanted a partial plywood deck on my first SOF, so I wrapped the hull skin around the bottom off-center (the cut-off was plenty to cover the deck). I then pulled it very tight and stapled it to the inside of the gunwale every couple of inches alternating sides and working from the center toward the ends. Once the hull skin was stretched and fastened, I cut the excess fabric and rolled the remaining one or two inches into a sorta' neat roll then re-stapled every inch. I skinned the deck ends by wrapping the fabric over the outside of the gunwales and stapling-cutting-rolling-stapling the same as the hull skin. 

 

The advantage is that skinning was a three-four hour job and the skin was so tight it took very little shrinking. Use stainless staples in a power stapler and go over them with a hammer to ensure they're fully set.

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Each to his own and I don't try to stop anyone from trying something different. Not that I could if I wanted too! 

 

...

 

Many people come along and feel the need to 'improve'  construction methods. I have incorporated a couple of ideas from one builder that actually improved my designs. Most, to me, just add complications with little if any advantage. But I am always open to new ideas if they improve the design while staying true to the low cost and simple appeal of the boats.

 

Right now I'm not trying to "improve" anything, just to understand.  I hold a firm belief that we need to know what came before, first.  I also know, for a fact, that the only way to know whether or how an idea or process works it to try it out first hand; there's no other way.

 

But I'm also willing to listen to the experience of others, and I'm not against stealing good ideas.

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Don't get me wrong. I have taken what most people do and improved on it (I think). My current designs have a lot in common with other designs out there, but there are some things I have improved and I am still working on some new ideas.  

 

It's just funny some of the ideas I hear that are steps back and not forward. Recently heard of someone trying to make some radical changes and just had to laugh at some of the 'improvements' they had in mind. They were taking the simplicity and tossing it out the window in the of 'improved'. 

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