Any way to build composite gunnels with out a vacuum bagging rig?

[stripperguy]

Oops, pics are in reverse order, you get the idea...

 

[Alan Gage]

I’ve had good results using a cedar “uniwale” as stripperguy described, but with 8 oz carbon fiber sleeve. Probably not as light as a foam core, but still came out to around 3 pounds all-in for 3/4 x 7/8 gunwales on a 14 foot pack canoe. And the wood is totally encased in carbon and epoxy so no worry about mushrooms, and no need for vacuum bagging.

Make the wood gunwale and dry fit until you are happy with it. Then round the corners etc. so you don’t snag the carbon, run it through the sleeve and liberally brush on epoxy. A gloved hand works great to squeegee it nice and tight, and get rid of excess.

Once it is dry to the touch, cut out the carbon that covers the slot in the gunwale with a box knife, and you will find that it is still flexible enough to follow the sheer line and attach with thickened epoxy. Finish up with additional epoxy to fill the weave, along with varnish for uv protection.

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That's some great info. I never had the guts to try that option because I didn't know if there would be enough flex afterwards for the gunwale to conform to the hull.

I imagine it's very easy to slice the carbon open to expose the slit when the epoxy is still green. I also image it would be a good idea, after wetting out, to have the gunwales sitting slit side down to keep epoxy from pooling in that area, which could be a mess to clean out.

Alan

 

[Traveler]

I imagine it's very easy to slice the carbon open to expose the slit when the epoxy is still green. I also image it would be a good idea, after wetting out, to have the gunwales sitting slit side down to keep epoxy from pooling in that area, which could be a mess to clean out.

The short answer is “yes” and “definitely makes sense but I don’t think that is what I did”. The long answer:

I did this over a year ago, so some details a bit foggy. I don’t recall any issues whatsoever with slicing out the carbon over the slot, but I was a bit nervous that the gunwale would be too stiff to bend over the sheer.

The first one I left to dry overnight suspended between two chairs with a small weight attached in the middle to give me some built in curvature from middle to bow and stern. But when I removed the weight I found that it did not really hold any curve and was still flexible enough. The second side I didn’t bother trying to pre-bend and it also went on fine.

I had no issues with build-up inside the slots, and the pre-bend I tried to do would have meant that it dried on it’s side. Maybe that was sufficient to redirect any excess epoxy, but squeegeeing out with a gloved hand removes pretty well all excess anyway. Next time though, I will be letting it dry slot down.