Fiberglass vs. Kevlar Question?

I’m looking at a used kayak. The owner doesn’t know what it’s made of, but it’s obviously a composite of some type. Any quick way to tell the difference by looking at the boat? This one has some fibre-type cross-striations, but can Kevlar also have this? I am quite naive here, and would appreciate any suggestions.

Tell us what model and how old…
Picking it up may give you a clue. Kevlar is usually smooth and a yellow parchment color, FG is a whitish.

the difference ?
my kevlar boats all have an obvious ‘weave’ effect going on inside the cockpit and hatches. sort of like chicken wire with smaller squares … or like screen, with larger squares.

my fiberglass boats exhibit none of the above. they are colored the same as the hull.

It’s a CD Gulfstream
A few years old. The interior has a gold, woven-appearing material. The outside is white and smooth. It may not really matter, but I would just like to know what I’m buying. Are these two materials really indistinguishable, or should I turn my 13-year-old son loose with his chemistry set to figure it out?

Sounds like kevlar…
All CDs are gel on the outside it’s the color of the interior. Golden would indicate kevlar… congrats…

look under the deck
the fiberglass model has pretty thick roving,each strand is about 3/16" wide,look under the deck,the kevlar model is kind of fuzzy under the deck, the weave is smaller on the kevlar, 1/16">

Not to be a wet blanket but…

A person that has a Kevlar boat usually KNOWS that it is Kevlar. It might be worth while asking the seller how he came by the boat…

because they spent $3000???
hmm,good point. But some folks just buy stuff.

Good point, indeed
I’m not a sophisticated kayaker yet, not knowing my Kevlar from my carbon or fibre. Fortunately, neither is the seller, who apparently inherited this kayak from his mother’s uncle’s nephew’s cousin’s former roommate. Thanks for the advice. I’ll let you know how it turns out.


Legit ownership?
Boat origin sounds very uncertain. Does the vendor legitimately own this boat?

So the guy doesn’t know what he’s got,
huh? He has this boat that got dumped on him that he just wants to get rid of?

I would look inside the boat, turn my nose up in disgust, make some comment about the crappy material used to make the boat and offer him $200.

Im Far From Expert
But Ive played around fiberglass boats for years. The weave that is seen on some boats can be glass or fiberglass. The glass can come in several forms. Glass cloth can be very fine weave looking almost like the weave in a tee shirt or very course and the consistancy of basket weave. Glass can also be applied with a gun and this is called chopped glass and is in fact pieces of glass mixed with the resin.

The vast majority of kevlar used in boats is actually a composite, or mix of fiberglass and kevlar. Kevlar is woven into the fiberglass cloth.


if it’s yellow/golden inside…
it’s Kevlar (or should I say Kevlar®…)

I’d look closely at the gelcoat exterior to make sure there are no areas of separation or blistering. Kevlar boats have more of a tendency toward that problem than glass boats. As long as you’ve got good adhesion throughout the boat, no reason not to get it.

Not true. Kevlar/glass mixed weave

– Last Updated: Apr-20-05 11:42 PM EST –

is not common at all in composite boats. In composite WW boats, the glass layers are outside, the pure Kevlar layers inside. In canoes, a few builders are trying carbon/Kevlar weaves, but most use layers of pure glass, carbon, or Kevlar.

This would show that builders are
stupid enough to use Kevlar as an outside layer, and to use gelcoat. Smart builders do not use Kevlar as an outside layer, and do not use gelcoat.

Of course, some originally smart builders give in to dumb customers who expect gelcoat.

An outside layer of S-glass, colored with a thin layer of pigment or painted with epoxy paint, will wear like iron, stay smooth, and contribute stiffness and resistance to compression damage in a way that Kevlar and/or gelcoat can NOT do.

I own a kevlar C.D.Gulfstream
I have a 2002 C.D. Gulfstream. In large letters on the exterior is written “KEVLAR”

Beware if that does not hold true on the boat you are looking at. I just thought you might like to know.

Charlie Winther

C D layups
are hard to diagnose over the internet. A girl in our paddling club has a CD Extreme in fibreglass.

The layup inside the cockpit definately has a yellowish tint to it and I thought it was a kevlar layup at first but on closer inspection I realized it was fibreglass.Must be the colour of the resin. If you can get the boat for a good price then buy it and enjoy,it’ll be fine no matter what the material.I too would be skeptical about whether the boat is hot or legally come by.


Good advice to heed
I appreciate all of the comments. I may just hold off for now, even though I’m sure the kayak is clean. Thanks.

core materials
I’ve seen a variety of constructions with CDs boats. Have they moved facilities in the last few years?

On of the Solstices I saw had a very thick corematerial (for a kayak),about 1/4" like a canoe. The underside of the hull had a depression from a scratch. I wonder if they’re experimenting. Too thick of core material doesn’t sound like a good idea because of the thinner skin that goes with it.

I was going to say
the inside of my fiberglas Caribou looks pretty gold too. Though a rather pale gold, certainly.