carbon vs. kevlar
Posted by: old_user on Apr-23-08 1:13 PM (EST) Category: unassigned
which holds its shape better at high speeds, 6-plus mph? people say stiffer is better, and i just wonder if paying the extra money for carbon is worth it. i paddle marathon canoes, so any percentage of a mph is a plus.
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Sounds like a Charlie Wilson question.|
Posted by: string on Apr-23-08 1:46 PM (EST)
I thought the advantage of carbon was weight savings.
Posted by: salty on Apr-23-08 1:49 PM (EST)
Posted by: OldBill on Apr-23-08 3:04 PM (EST)
Give you a technical answer but when you go to a big marathon race all the top boats are black.
carbonite plus kevlar|
Posted by: pagayeur on Apr-23-08 4:30 PM (EST)
CEW can explain this much better than I but here goes: kevlar has many strengths but lacks tensile strength. In other words it is a bit brittle and could crack. Carbonite is light and has good tensile strength so the combination of kevlar and carbonite makes for a stronger lightweight hull. Plus, black and gold is a good color combination.
"Lacks Tensile Strength"?|
Posted by: guideboatguy on Apr-23-08 5:09 PM (EST)
Posted by: pagayeur on Apr-23-08 10:42 PM (EST)
I always got those two things flip flopped. I'm no chemist, I just remember when Bell started the Black and Gold series, CEW told me at a canoe symposium that one lacked tensile strength and the two together made a good combination. That was good enough for me. I really enjoy paddling the B G series. Bought my wife one too.
I sort of suspected as much.|
Posted by: guideboatguy on Apr-23-08 11:02 PM (EST)
That's why I started off my reply to you with a question asking if that's what you really meant to say. I guess I didn't "explain" anything you didn't already know :)
There might not be a straight answer|
Posted by: guideboatguy on Apr-23-08 5:17 PM (EST)
When I bought my Merlin II, I had the choice of buying one with a carbon hull (I can't recall what Bell calls this material) or Kevlar (which in this case Bell calls "Kevlight"). I pushed and poked the hulls of both boats, and the carbon boat was a lot stiffer on the sidewalls, but I'm not sure there was much difference in stiffness on the bottoms, where the foam core is used to stiffen the hull. Maybe the carbon boat was stiffer on the bottom as well, but if it was, I wonder if it would make enough of a difference to counteract the rather significant weight advantage of the all-Kevlar boat. There's certainly more than one issue to think about here, if marathon racing is the boat's purpose. Fortunately, I'm not a racer and didn't get too stressed-out about the decision. I ended up buying the cheaper boat!
my experience with matrix carbon/kevlar|
Posted by: damiano on Apr-23-08 9:00 PM (EST)
I recently purchased two sea kayaks (I'm sorry if it's not exactly releavant to the craft in question but the material seems to be) in Kevlar/Carbon weave matrix.
Posted by: old_user on Apr-23-08 9:15 PM (EST)
Unusual issue to have with an epoxy based composite. If they were very recently built they may not have reached a final cure, otherwise they are getting really hot due to the black of the carbon, hot enough to approach a temperature transistion point for the resin where it gets soft.
Posted by: paddletothesea on Apr-24-08 12:21 AM (EST)
I've often wondered if it makes any difference. When you look at the "time results" for say...the Ausable Marathon or the Le Classique....the "times" are about the same over the last 15-20 years however the boats have gone from kevlar to 99% Carbon... So what Im saying...in the 80s, kevlar canoes were paddling the Ausable(120miler) in the 14-15 hour range for the top 15 teams. Today...the top 15 teams are still coming in at 14-15 hour but are all paddling Carbon boats... So whats the draw there?? Seams like if you work on the engine and train more it will make up for it. I think S. Corbin could have won any of hi recent Ausables in a Kevlar canoe instead of his Carbon.
Posted by: CEWilson on Apr-24-08 8:38 AM (EST)
Posted by: salty on Apr-24-08 5:22 PM (EST)
and I would totally agree with the comments about Vinylester being a great resin overall.
Posted by: CEWilson on Apr-24-08 7:26 PM (EST)
dam quriky resins|
Posted by: old_user on Apr-24-08 8:36 PM (EST)
epoxy- great cept for that UV degredation
Posted by: CEWilson on Apr-24-08 8:57 PM (EST)
Our biphenol based Vinyl Ester has a 6 month shelf life. As we use a 55 gal drum every 6 weeks, degredation is hardly an issue. And, it certainly is not an issue once catalyzed and gelled. A larger issue w/ VE is the smell. No one with a house mate will ever live to finish a stripper in an attached garage.
Posted by: salty on Apr-24-08 9:16 PM (EST)
Posted by: old_user on Apr-25-08 12:16 AM (EST)
I have a kevlar kayak and added another layer of fiberglass and epoxy to the hull under the seat and feet area. It added some stifness as well. So, you can repair kevlar real easy and make it stiffer in critical areas if you want. Not sure about carbon.
could it be that the bond|
Posted by: Dirk_Barends on Apr-25-08 2:41 AM (EST)
between the resin and the polyester fibers is better than with Kevlar fibers?
Posted by: CEWilson on Apr-25-08 8:42 AM (EST)
Sweet Composites has a very informative web site that provides basic info on resins, fabrics, coatings and capabilities.
How about S-glass and cedar???|
Posted by: old_user on Apr-25-08 11:44 AM (EST)
One more material to consider...