Kevlar damage question and pic

-- Last Updated: Jul-22-10 11:15 AM EST --

My "new" TW Special came with a bit of a racing bruise from the original owner and his partner. They thought they could make it over a log. From the looks of it, they didn't get far and then fell over.

The area is not at all soft. On outside all you really see is some minor gel coat cracks.

My question is, would you fix this with glass or kevlar on the inside, or just leave it? I'd kind of like to fix it with kevlar but two concerns: (1) I've never done much at all in the way of composite repairs (2) I'd kind of like the repair to look good (3) new kevlar is going to stick out like a sore thumb against the aged and golden kevlar

Thanks in advance

If you do a repair…
use Kevlar.

If you’re not in a rush, you can darken the cloth (assuming you get a fresh peice of KV) by leaving it exposed to the sun for an extended time. Either way, a nice, neat, clean job won’t look as bad as you think.

If it was my canoe, I would do the patch, as the damage is in the chine. But, If I was talking to a repair customer, I’d say it’s not absolutely necessary, but recommended.

Call me if you want.



– Last Updated: Jul-22-10 2:36 PM EST –

I was thinking about putting some new kevlar out in the sun to get a bit of patina. But I didn't mention it for fear of getting laughed out of the place!


I'll probably take you up on your kind offer when I'm ready. I'll be getting the oil-based Valspar porch enamal from the hardware store this evening. The bare spots on the football are from me removing the original owner's kneeling pads.

Thanks again for the help.


I think s glass is easier
But I’m certainly not a repair expert. S glass wets out easier so the repairs are as light or lighter than kevlar and as strong. For a ding like that I’d just paint on some clear epoxy and watch for leaks. If it started to get worse, then I’d do the repair or have it done.

Kev and Peel Ply
I agree with Rob, I’d patch with Kevlar because the flex characteristics will match better than glass.

You’ll also want to use VE resin, Derekane 8084 will match flex and bond best, but cross link is not possible on an older hull.

We found that peel plying the edges of Kev patches flattens them wonderfully. Certainly sanding Kevlar edges is contra-indicated. Kevlar and peel ply can be acquired from Jamestown or Sweet Composites in small lots.

I’ve a written protocol for internal patches that was used at Bell and updated for Placid that I’ll forward. Email me at if you want it.

what has happened to your canoe is …

– Last Updated: Jul-22-10 3:17 PM EST –

...... considered a "structural fracture" , no if ands or buts about it .

It is so simple to reinforce/repair that not doing so would be neglegent in my mind and asking for future much more serious complications to happen . The sooner you fix this the better off you'll be .

The lighter color areas that show on the interior are a clear evidence that the resin has fractured , is seperated away from the cloth , the resin cloth bond has been compromised , the uni bond is broken .

I would not hestitate to make an E glass reinforcment patch over the intire area . I do not know what the layup of your canoe is ... if any other type cloth has been used on the outside (S glass outside is a likely possibility) , it may be fractured worse than the kevlar because it will be less flexable , it is harder tensile wise (less flexable).

The first thing that happens when such an impact deformation occures is ... the resin and cloth stretch as a unit (uni) ... next in severity is the resin and cloth bond is compromised and seperation occures (this much is at least evident in your case) ... next some of the strands in each cluster begin to fracture or break because of overstretching (this usually begins at the hump in the weave where the cloth fiber clusters go over and under each other) ... once the resin has been seperated as a uni bond to the cloth (compromised) , and the individual fiber strands in the clusters begin to fracture , complete breaking of all strands in clusters and tearing of the cloth comes next . A break in srand cluster is a complete seperation (not just some individual strand fibers beaking) . A tear is many strand clusters breaking in a given line or lines .

Two layers of 6 oz. E galss weave cloth on the interior is what I would do . 205/207 , I would use the West System 207 hardener because of it's clearity and no (0) amine blush ... West System resin is 205 .

Unfortunely you will need to sand through at least the top resin until you scratch the existing cloth (this will also break some more fiber strands). It may already have (and most likely does) signifigent strand breaks , especially because it is a weave . Ideally what you would be wanting to achieve is , during sanding , repeatedly wipe the area with acetone rag until you do not see any more whitish (lighter) color when wet with the acetone . This tells you that any newly applied resin will make direct contact with what's there , and no (or as little as possible) air space can be trapped between new resin and underlying materials .

I suspect your hull and chin have some deformation even after springing back into near original shape . If this is minor and you can live with it , just be certain that the new resin and cloth applied is making full contact over the repair reinforced area (avoid allowing air to become trapped between new resin/cloth and existing material when setting the patch .

If you need a pointers on how to prepare and make the resin/cloth patch , just ask ... a few tricks save much mess and ehance the final product .

You may want to sand away the gelcoat on the exterior , avoiding cutting any more cloth strands than is possible , fair and re-gelcoat .

Other than making the structural enhancemebt to the compromised area , you are also wanting to keep water/moisture from getting into the structural fracture which will cause further degradation and structural compromise . Fix it before it gets worse is my recommendation , it's a nice canoe .

ps., ... if you desire to use kevlar and vinylester resin as Charlie recommends for flex-ability , go for it . I do not feel that restoring original flex is even a remote possibility , the area will be much stiffer regardless of which cloth and resin after reinforcement patch (The epoxy will be a little more flexable than the vinyl ester resin also . I suggested 205/207 because the area patch will be clear almost invisable after cure .

You say its not at all soft, and the
picture suggests that while there may be some micro cracking in the resin, there is no delamination.

I suggest trying Eric Nyre’s suggestion of thinning vinylester and painting it over the surface. Talk to Eric and see what he thinks.

If I were to do anything, I might order some polyester cloth and put a single layer over the stressed area. Wets out OK, and clear. Sands easier than Kevlar. I would not use glass inside. Scuffs and makes itchies.

I have an '82 Kevlar/vinylester Noah kayak, and the chines are stressed similarly from use. Because there is no gelcoat, it is easy to see the nature of the (minor) damage. It is NOT consequential with regard to the use of the boat.

Charlie mentioned VE resin too

Where do you get small quantities? I don’t see it on Sweet’s site.

If I do the diluted/saturation method first and want to patch it later, do I compromise anything by doing the dillution/saturation first?

in the first place …

– Last Updated: Jul-22-10 5:34 PM EST –

...... vinyl ester resin is already very thin , has very low viscosity , do not thin it .

General vinyl ester resins are made by esterfication of rather cheap epoxies to begin with , then the by product of that esterfication is severely diluted with high percentage of styrene ... this is the product you get in the can .

I would not do a temporary wipe fill with VE resin , or any resin for that matter , it will only make matters worse when you discover you need a reinforcement cloth patch of the whole area .

If you must and intend to do a wipe fill , at least prep. the area as previously described , and use the West System 205/207 epoxy ... it will have the least chance up cracking up (or lets say it will crack up less) , and the best chance of a proper repair in the future (which will not be as strong or as good after the fact as it would be doing it properly with the E glass and expoxy right off the bat) .

If your intention is to just help keep moisture/water out of the composite lay up to deter further degradation ... the epoxy is your best choice by far .

The 2 layers of 6 oz. weave E glass and epoxy repair/reinforcemnt is so easy to do why would you do anything at all if not that ?? .

I think one more whack on that damaged area will fix it good !!

Do some more research on vinylester.

Colden Canoe

– Last Updated: Jul-22-10 9:59 PM EST –

Paul Meyer of Colden Canoe is going to sell me a pint.

Thanks Paul!

And ness and hopsing are going to pick it up for me.

Thanks ness and hopsing!

Thanks to you Charlie Wilson for giving me your repair protocols and source suggestions for the VE.

I hate to be a spoil sport, but
If I were you I wouldn’t use kevlar. I would use fibreglass.

Kevlar is just about impossible to cut. You are going to end up with a bunch of fuzz and lots of cussing

I have repaired our kevlar racing canoes many times and after the first attampt with kevlar never used it again.

If you do a good patch job with fiberglass, you can hardly tell the difference.

jack L

Boy am I getting an education.
Are you guys saying that that cracking sound when I try to bump and jump logs with my Kevlar kayak is bad? Should I look inside the hull?

Man I just knew that polyethylene was better for me!

Can you recommend a poly boat that paddles just like my Solstice GTS?

I wouldn’t say that S-glass wets out
easier than Kevlar. It depends on the weave of the S-glass. The fiber bundling in S-glass is kind of tight, so it does not wet out and set up “clear” like E-glass.

Glass is so much heavier than Kevlar that if one uses the same size and shape for patch pieces, a glass patch will always add more weight.

There is no absolutely hard and fast rule for choosing cloth for patches. But just as the rule for layup is glass outside, Kevlar inside, usually Kevlar is the best choice for inside patches. An example of an exception is when patching relatively sharp chines on whitewater boats that have been broken because they were squeezed tighter when the center of the boat was pushed upward. Because the chine damage was done by compression, and because Kevlar is only so-so in compression, such chine damage is better repaired by S-glass or a combination of glass and carbon.

I’m betting that if you do further
examination of that boat, you will find that it is not weakened. Invert it on sawhorses out in the sun, and look from underneath. I think you will be surprised by the lack of delamination or deep damage.

Thump the damaged area, and thump the other side, and listen. If there is no difference in sound, what might that tell you?

With someone stabilizing the boat on the horses, lean really hard on the outside of the damaged area, and lean hard on the other side or on a similar area. If you can feel no difference, what might that tell you?

Many, if not most, MR “Kevlar” canoes are pure Kevlar. I don’t like a pure Kevlar layup, but it will stand up to a ride over a log pretty well.

I don’t think you can do a perfect aesthetic fix on the boat, any more than I could remove old scars from an antique harpsichord. An antique is an antique.

If it’s just on that one side …
… damage from jumping a log wouldn’t be my first guess as a cause. More like being pinned or being dropped. Log damage would usually be on the bottom and/or on both sides.

Probably doesn’t matter.

Doesn’t look so bad to me, and if it’s not soft at all or delaminating, I wouldn’t worry about it until that happens, if ever. But I’m lazy and have no repair skills.

What does the outside look like?