jaguiler Posted July 2, 2014 Report Share Posted July 2, 2014 Hello everyone, Assuming the Kevlar is affordable and comparable in price to other materials - how would it be for a skim material ? Has this been done ? I know Kevlar does not stretch - but does it behave like Nylon, where it wrinkles, or more like polyester ? Also - what type of coating sticks to Kevlar ? regular paint or is it a picky material to finish with paint ? Thank you ! John Quote Link to comment Share on other sites More sharing options...
Ekapi Posted July 13, 2014 Report Share Posted July 13, 2014 Kevlar would be crazy expensive in a weight suitable for covering a kayak, and I suspect it would require an epoxy coating, which creates a whole new set of problems as well as expense. It doesn't stretch or shrink, and so would need to be sewn tight right from the start. Quote Link to comment Share on other sites More sharing options...
Abyssdncr Posted May 21, 2016 Report Share Posted May 21, 2016 I was thinking this same thing this week and found 14 oz fabric for $15/yd. Just got back for an 8 mile jaunt down a rocky stretch of the Arkansas river and some extra armor would definitely be a good thing. Rented some Tupperware for $15 instead of sending FreeB down it sight unseen - probably a wise choice... There was a gal there in a Gentry Mobyjack Bay (the actual red one on his website), that Dave made for her personally and she survived mostly unscathed, just a couple scuffs along the keel...but that boat doesn't sit very deep in the water. So, again I'm back to wondering if an extra layer of Kevlar over the poly on the bottom half of the skin would help in this regard... Quote Link to comment Share on other sites More sharing options...
PAR Posted May 22, 2016 Report Share Posted May 22, 2016 14 ounce Kevlar will become 35 ounce fabric once the epoxy fully saturates the material. Good luck getting a smooth finish with hand laid techniques. Quote Link to comment Share on other sites More sharing options...
Action Tiger Posted May 22, 2016 Report Share Posted May 22, 2016 There is no epoxy on these boats, except maybe to glue scarfs or laminated coamings. I'd be more worried about how it takes and holds stitches... Quote Link to comment Share on other sites More sharing options...
Abyssdncr Posted May 22, 2016 Report Share Posted May 22, 2016 PAR, you may be absolutely right, but even at 35 oz, that's a 2 lb weight hit, which is still a 15 lb savings over Tupperware. I was thinking some graphite epoxy mix over the Kevlar from the chine stringers down. Still not Tupperware durability, but also still not as expensive as plastic and far more classy, even if the surface doesn't flow out glass smooth. Sure, it's a compromise, but the weight penalty is almost negligible and aesthetics aren't a primary driver. Armor is never cheap though, in price or weight. In KS, rapids are a wishful pipe dream, but the bedrock is very real... Quote Link to comment Share on other sites More sharing options...
Action Tiger Posted May 22, 2016 Report Share Posted May 22, 2016 Okay. I'm out. Rigid cloth is inappropriate for this type of construction, as I've learned the hard way. Good luck. Quote Link to comment Share on other sites More sharing options...
Abyssdncr Posted May 22, 2016 Report Share Posted May 22, 2016 Okay. I'm out. Rigid cloth is inappropriate for this type of construction, as I've learned the hard way. Good luck. Ok, to be honest, I think my experiment vessel is going to be FreeB lofts, narrowed about 20% to around 22.5" (frames are cut, but until the gunwales are attached, no way to know for sure), converted to multi-chine, and built seam-batten style using 1/8" Baltic birch, so the epoxy coating materializes a little differently... However, with SOF in mind, same doubling with Kevlar (chine stringers down) using Corey's goop? Quote Link to comment Share on other sites More sharing options...
Kudzu Posted May 22, 2016 Report Share Posted May 22, 2016 Assuming you did us it, what do you expect to gain? What advantage does it have? It maybe be stronger but punching holes in a boat is rarely an issue unless you hit something sharp going very fast. And most of us can't/don't paddle very fast. While an improvement, I see it as minor. Repeat abrasion is the the only real enemy these boat have (used as intended). Repeated beaching on something like a concrete boat ramp will grind a hole in the fabric fast! That is why I recommend rub strips. Does Kevlar/epoxy mix have higher abrasion resistance? I have not researched it in depth but it sounds likes Kevlar doesn't have much resistance at all and is mixed with other fibers when abrasion resistance is needed (nylon an/or polyester). Epoxy has some resistance but from my very limited research it doesn't sound like there much if any gain with the two. If you looking at white water, these boats are not designed for white water or moving water! If you are using the boats in moving water against my recommendations I would be more concerned about the frame strength. I have seen canoes wrapped around rocks in current and the thought of a skin kayak collapsing around me.... Since Kevlar has no stretch, if the weave is tight it would be very hard to sew on without lots of bunching and wrinkles. If the weave it loose then it might be OK. Maybe I am wrong but when I have looked at it it seems to me like you gain puncture resistance. Youhave more cost, and additional weight. While I am all for new ideas, this appears to doesn't appear the have any real advantages to me. The appeal of these boats is the low cost, lightweight and ease of construction. Epoxy/kevlar skin takes away a little bit of all of those. Quote Link to comment Share on other sites More sharing options...
PAR Posted May 22, 2016 Report Share Posted May 22, 2016 I agree in that Kevlar isn't a good choice, but it's puncture resistance is why it's one of the dominate fabrics in bullet proof vests. It's also quite good with abrasion. Pound for pound, I think there are better methods and materials, particularly when you look at the cost/reward aspect. Quote Link to comment Share on other sites More sharing options...
mitchmellow Posted May 23, 2016 Report Share Posted May 23, 2016 If you wander the web you'll find the topic of improving the skin strength/abrasion resistance/puncture resistance of skin boats many times. Dave Gentry was working PL Premium (a polyurethane construction adhesive) into the fabric in areas of potential abrasion. He believed it helped but I have not seen it quantified. Ross Miller has an article on Duckworks describing a dacron/xynole/epoxy layered covering ( http://www.duckworksmagazine.com/07/howto/skin/index.htm ). I don't think he says anything about how much weight it adds. Bill Hamm has used 4 oz. cloth covered with 4 oz. fiberglass and resin ( http://www.kayakforum.com/cgi-bin/Building/archive.pl/bid/13/md/read/id/193480/sbj/skin-on-frame-fiberglass-on-cloth/ ). Again, I've not seen any info on how much it improved the integrity of the skin and how much weight it adds. There's a thread on the Kayak Forum about Kevlar ( http://www.kayakforum.com/cgi-bin/Building/archive.pl/bid/11/md/read/id/50919/sbj/kevlar-skin-on-frame/ ). I believe it is just a discussion among members and doesn't draw any real conclusions. It's hard to say how successful any of these methods are. It seems it would be an individual decision. You can only change the inherent characteristics of the method so much and still have a skin on frame kayak. Quote Link to comment Share on other sites More sharing options...
Abyssdncr Posted May 23, 2016 Report Share Posted May 23, 2016 I just tried the PL Premium on the the young prince's boat - not impressed. Leave it thick enough for abrasion resistance and it looks hideous; sand down the high spots and risk abrasion to surrounding areas. It did fill in the weave of the economy fabric very nicely though and it dries quickly. I think there is a place for that product in the toolbox somewhere, but not so much for this purpose. Also, I misspoke on the 14 oz Kevlar fabric; it's $35/yd... Quote Link to comment Share on other sites More sharing options...
Rich D Posted May 23, 2016 Report Share Posted May 23, 2016 I just tried the PL Premium on the the young prince's boat - not impressed. Leave it thick enough for abrasion resistance and it looks hideous; sand down the high spots and risk abrasion to surrounding areas. It did fill in the weave of the economy fabric very nicely though and it dries quickly. I think there is a place for that product in the toolbox somewhere, but not so much for this purpose. Also, I misspoke on the 14 oz Kevlar fabric; it's $35/yd... My impressions were different. I used the PL Adhesive on the economy fabric and, so far, have been quite impressed. I used the PL on both deck and hull. I thinned it with Mineral Spirits and squeegeed it on, then brushed it smooth (2 coats). Got a smooth finish and it only took 1 quart of Rustoleum to do both hull and deck. Seems very durable but needs more use to be sure. Quote Link to comment Share on other sites More sharing options...
Abyssdncr Posted May 25, 2016 Report Share Posted May 25, 2016 Ok, y'all win, bought a Perception Swifty 9.5... Quote Link to comment Share on other sites More sharing options...
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