Professionally, I am a clinical
psychologist, so don’t expose more of yourself than necessary. I do not see why it is necessary for me to have actually built a boat to comment on boat construction. Do you? I have no more general bias against QCC than I have against Toyota, though I somewhat prefer Hondas. The fact is, you have gotten yourself into a hissy fit from which you now cannot escape.
QCC is a solid composite - Not Cored
Kevlar makes more sense on the inside of a cored structure.
A QCC is solid composite structure without a core. The whole layup is about 1/8" thick. This means the inner layer of composite will deflect nearly the same amount as the outer layer. There will not be a significant difference in the amount of tension a Kevlar fiber is put in whether it is inside or outside.
Kevlar has very poor abrasion resistance. I’ve completely worn through the inner layers of my old Kevlar QCC700. Fortunately all QCCs have a light layer of glass as the outermost layer against the gel coat. This provides great abrasion resistance. Carbon and glass have much better abrasion resistance than Kevlar.
For these reasons it makes more sense to not use Kevlar on the inside exposed surface of a kayak if the kayak is non-cored.
I don’t like Kevlar in kayaks because it is not stiff enough compared to glass or Carbon. However, I think a good application would be the inner layer of a cored surfski.
Still, if given a choice I personally would choose carbon/core/carbon because stiffness is more critical to efficiency than most paddlers realize. Certainly a heavier paddler in rougher water would want the stiffer layup that carbon provides over Kevlar.
love it
I love your first line of that post g2d.
(I’m sitting here reading this waiting for my kevlar kayak to dry so I can actually lift the darn thing…)
Agree with some of your points, but
Kevlar inside on non-cored boats doesn’t seem to be associated with any consistent problems. My used (~6 years) S-glass out/Kevlar in c-1 does not shoe any interior wear, or breaking. One of my kayaks is Kevlar inside, CAP outside, and I will have to watch for indications my heels are wearing through the Kevlar.
stiffness ? will you notice, I doubt it!
I have 2 racing canoes, one kevlar and one carbon, they say kevlar is lighter, carbon stiffer. Forget all the that and enjoy paddling. If you’re not racing (sounds like you’re not) will you notice a differnce, no! Treat your boat with care and leave it out of direct sun and you’ll have years of use out of your boat!
It’s all makin sense now!
It always surprises me to hear that
Kevlar is lighter, while carbon is stiffer. The stiffer part is correct… Carbon in resin is really stiff. Carbon cloth is also lighter than Kevlar cloth, for an equivalent amount of stiffness contributed to the laminate.
People associate Kevlar with lightness, but that is because Kevlar’s toughness, combined with some glass or carbon for stiffness, makes for a lighter overall laminate with the same or better resistance to breakage. For some purposes, it is possible to make a boat with pure carbon, or with S-glass and carbon, that is lighter and stronger than a similar all-Kevlar layup. There are no GOOD solutions based on use of just one boat fabric. It always takes two, or three.
Not to me. If you understand what wolfy
means by “not professional”, please clue me in. Does he mean I am not a professional QCC engineer?
Coring can make
any material stiff. Once again note Epic’s use of core material in their ultra light kevlar lay-up. Core compensates for Kevlars weakness in compression. Wenonah uses the same engineering. I think smart people who genuinely want to understand composite technology will move past this site and consult with composite professionals and composite engineers rather than psychologists! It’s very easy information to obtain. Search composite / plastics suppliers such as Revchem, or Composites 1, NW Composites etc. Get the #, pick up the phone and speak to a technical representative. Then talk to many kayak BUILDERS and learn their varying approaches to meeting specific needs.
Good…you’re learning!
Walbridges Manual
I lost mine!!!,damn that’s a good book.
See, Salty, you’re trying to elevate
your invisible “professionals” while denigrating the solid practical experience of the canoe and kayak community. We’ve been through this before.
I found an interesting abstract on how soaking makes a Kevlar epoxy laminate stronger. Interested?
Oh, and Salty, as far as I can tell, you
are only pretending to have talked to a variety of kayak builders. Most of what you have cited in your posts and emails to me has pertained to yacht and powerboat builders.
I’m an
oppositional defiant, passive aggressive. Are you in a defensive crouch again?? People don’t buy G2’s amature opinion, and off we go! I know many kayak builders 
Relax G2, and work on that roll OK. Should this be on a different forum?
yes
don’t toss it on the ground
Envyabull
You are correct about weakness in compression, but Kevlar is pretty tough in abrashion resistance. That doesn’t mean it won’t abrade. Several builders utilize it’s abrashion resistance to reinforce keels, particularly on expedition boats. Zodiac uses it only on keels for wear resistance. It’s tensile strength lends it to impact resistance as well. There are other issues with the material that have been discussed to death. It has applications, but like you, I prefer Carbon / Glass.
So far at least zero mention of
bulletproof … Doh !!!
Another thing not mentioned was the very chip in question might have popped off cleanly due to not being grasped by layup during the build.
If the kevlar, carbon, glass etc. looks ‘shiny’ where the gelcoat popped, it was never bonded to it in the first place.
Send it!
I think I’ve browsed that, but I’m open to hearing more. Not suprised. Another interesting phenominon about Kevlar is that UV exposure can make it “stronger”. Sampsonite learned this.
attracts lightning
no one mentioned that. (joke)
you have
exposed too much of your self already, don’t you think?