Repairs with epoxy resin

This weekend I will be attempting a small repair job using West System epoxy (packs). I ahve developed stress cracks in the interior Kevlar laminate covering each of the two foam ribs adjacent the seat in my Magic. Apparently Bell never contemplated a 285#er paddling this boat. Anyhoo, I am going to add several layers of E-glass to the surface of the interior where the sharp radius creates a stress.

I used to do much glassing with polyester back in the day, so I am not a neophyte.

My question is: After I apply and wet-out the glass, apply the stretch wrap to one side’s repair, and after teh resin gels, how long should I wait to turn the canoe onto it’s other side to perform the repairs on the second side? (boat will be on-edge for the repairs).

OK. Another question. Do any of you go to the trouble of varniishing the surface of the repairs to protect the resin from UV?

And what advice might come out of Duckhead Central?

Respectfully submitted,


Analyze the kind of stresses the added
cloth will face. I use bias-cut Kevlar for interior repairs, but I admit there are a few situations where likely stresses may involve compression rather than tension. For those, E-glass would be OK. If you were here, I’d give you some Kevlar/carbon weave.

Not knowing which hardener West is using in those 2-packs, I think you can get the whole job done in one day. Just see that the resin on the first side feels pretty firm (not necessarily rock hard) to a fingernail before you reposition for the second side. Also, because the resin on the first side may not be completely set, try to see that the positioning for the second side does not impose any significant warping force on the first side.

The repairs are to the tumblehome area, ands will be in compression. That is the reason that I didn’t want to use Kevlar for the repairs. I figure that I will laminate three layers (3", 2", 1") and see how it holds up. I am also going to install a couple planks of minicel under teh seat to take a bit of the weight.

Glad to hear that I can most probably reposition the boat for the second side repair the same day. Oh yeah, the resin is 105 with 205 fast hardener.


You mean in compression because
of the tendency of the seat hanger to further curve the tumblehome? That would be true. But if you were reinforcing the same area to repair rock damage from outside, you might use Kevlar because further outside damage tends to put the inner layers in tension.

This is something people can forget, because, for example, if the stern of a boat strikes a ledge on the way over it, the point of impact is mainly in compression. However, often the breakage occurs several inches to either side, because pushing the center of the stern in causes the chines to be put in tension. So in that situation, if the chines break on the surface layer, one might want to patch with Kevlar, or with Kevlar/graphite.

Not related to the repair directly
Hey Jim -

I had a white gold Magic that flexed quite a bit in the tumblehome under my 230lbs. My latest Magic is black gold and the flex is completely gone.

I know that sounded like “spend more money”, but it wasn’t meant to!

Unfortunately kevin
Mine is a Black Gold! The stress cracks are very minor, only inside in the Kevlar and nothing showing in the exterior carbon. I just figgered it would be wise to nip teh problem in the bud.

Gotta get back to a healthy weight too!


PS: Check is in the mail.

PPS: Really! With a little extra for a set of padded yoke pads.

neophyte here
I can kind of conjure up in my head how you use plastic film over the epoxy on the outside of a curve. But, how would do you go about it on an inside curve?


A guy who bought his first ever West System a month ago and is still too a’scared to even open it

Only for a slightly smoother
finish. There is no way I can conjur up to tension the film, so I planned on simplu smoothing it with a foam squeegee for cosmetics.


got it, thanks
I thought I was missing something semi-obvious.

can place weight on the film, curved to fit the contour…it squeezes out the extra resin and smooths the job :slight_smile:

Best Wishes


I actually thought of
using a dry bag full of warm water, but I worry about seepage. Worth investigating though.


And here I was afraid…

– Last Updated: Jun-06-07 2:26 PM EST – were going to say the backband caused the problem!


By the way - self-employment dropped me down to about 195 (and I still eat ice cream and drink beer - but never at the same time)

How about a bag of sand?
If it seeps, it’s just there for grip, right?

Once again
the beauty of P-Net makes the cost of membership well worth it in terms of advice gathered!

And I happen to have a good supply of fine, dry playground sand.



Put a piece of softish foam over the
film, then apply weight to the foam conservatively.

I was watching Discovery Channel’s How Things Are Made, and they used the vacuum method to make a cello out of carbon fiber and heat-cured epoxy. It was interesting to see the same methods used to build boats and some aircraft parts.