Fiberglassing (and lessons learned)

March 3, 2018 § Leave a comment

No matter how many boats you’ve built, each build invariably provides a humbling lesson.

For this build, and having fiberglassed many times before, I opted for some faster curing epoxy. I was better at it, after all. Knew my business. Right?


Having wetted out maybe a quarter of the canoe, the epoxy started to kick/react, and I was left with a steaming pot of epoxy with no reasonable way of applying it without totally butchering the job. In the end, I capitulated, peeled off the fiberglass I’d wetted and rescued as much of the unwetted cloth as I could.

So it was back to what I knew best — slow cure epoxy applied at temperatures near 20 degrees Celsius. (This temperature limit comes as a result of another hard-earned lesson. With my last boat. I applied a coat of epoxy at 10ish degrees. It never cured properly and remained tacky.)

At any rate, back to this build. Armed with slow-curing hardener, I tackled the task again. This time, things went smoothly and the fiberglass went on with no appreciable air bubbles (I sealed the hull with a coat of epoxy before glassing). After that, I filled the weave with three more coats, using a pretty saturated foam roller to apply the epoxy, and a foam brush to smooth it out and remove the minuscule bubbles that would appear.

With that done, it’s time to flip the boat and sand the inside.

Fiberglassing the canoe ends

June 15, 2011 § Leave a comment

Someone recently asked how the ends are fiberglassed, so I thought I’d dedicate a post to that.

When I glass the hull, I cut back the cloth so that it follows the curve of the bow and stern but doesn’t quite go around. When the fiberglass has dried, I sand down the jagged ends so that the fiberglass is smooth where it meets the external stem.

To cover the bow and stern, I use the excess cloth that I trimmed off when I initially covered the canoe. I apply some epoxy to the area that I want to cover and position the cloth. The epoxy helps keep the cloth from sliding off the boat while I fiddle around with placement.

When the cloth is in place, I apply epoxy with a brush. I normally cut a slit in the cloth as I follow the curve to keep the cloth from bunching.

fiberglassing canoe ends

From this point, it’s just a case of wetting out the cloth and ensuring that it lies flat against the surface.

I then add a second, narrower strip over the first for added protection.

fiberglassing canoe ends

The end result looks a little Frankenstein-ish, but sanding the layers when they are dry renders the seams invisible.

Fiberglassing the canoe

June 13, 2011 § Leave a comment

I haven’t updated the blog since finishing the stripping because… well… sanding isn’t that interesting. That said, I was careful to sand away any glue lines between the strips because these invariably appear as white lines and look gross. I also filled any gaps between strips with epoxy and sanding dust. Bigger gaps (there were a few) were filled with cedar splinters and epoxy.

But at last, with the sanding done, it was fiberglassing time. With the exception of a few hiccups, the glassing went well and I’m happy with the results.

fiberglassing a cedar strip canoe

Glassing the inside

March 26, 2011 § Leave a comment

I’ve been slow to update the blog, so here’s a quick update.

Last weekend, I recruited a friend to help me glass the inside of the canoe. It’s helpful to have an accomplice to mix the epoxy and catch the runs and drips and, of course, to enjoy a beverage when the work is done.

canoe building:fiberglassing the inside

Catching the wayward drips and removing excess epoxy…

You’ll notice the clips and clamps along the edge of the canoe. After a short while, we got rid of them. Once the glass is wetted out, they tend to get in the way and prevent the glass from properly adhering to the wood.

The finished product…

You’ll notice that I’ve started sanding the outside of the hull in anticipation of eventually varnishing it. The sanded bits look milky.

On a side note: The mind is a remarkable thing in that it is able to suppress unpleasant memories, so that when the unpleasantness occurs again, it’s new and fresh. To wit: I was again able to suppress the knowledge of how much sanding was involved in building a canoe. The very term “building a canoe” is misleading. Sanding is at least half of the effort and seems to bookend every phase of the project.

That said, now that the canoe is fully glassed, I can start to see the light at the end of the tunnel. Here are the things that remain to be done:

  • building and installing inner and outer gunwales
  • mounting seats and yoke
  • mounting the decks
  • building and installing the bulkheads (something I’m debating)
  • sanding, sanding, and more sanding
  • drink some beer to celebrate the end of sanding
  • varnishing (and lightly sanding between coats)
  • drink some more beer to celebrate the completion of the project

Fiberglassing the hull

March 5, 2011 § Leave a comment

Canoe building factoid #4 — The most under-appreciated fiberglassing tool is a belt, for it is invariably when your latex-gloved hands are coated with epoxy that your pants decide to migrate.

Today is the day I fiberglass the outside of the canoe. I’ve recruited a friend to do the mixing while I spread the epoxy. It’s important to select a friend for whom curse words will not cause affront.

My preparations included vacuuming the shop and getting it as dust-free as possible. The last thing I wanted was to generate airborne dust as I shuffled around the canoe. Wet epoxy or varnish are dust magnets. I also lightly sanded the hull and then, realizing my mistake, vacuumed again. Finally, I got the heater running as the shop temperature was under 10° C/50°F.

By the way, Nick Schade has a great video on YouTube that shows him fiberglassing a kayak. You can find it here.

The reason I bring up the video is that I could describe the technique, but watching a master do it is far more informative and rewarding. In fact, I fiberglassed my first kayak based on reading only. After seeing the video, I realized all of the things that I could have done better and differently. Now I make a point of watching it whenever I’m about to fiberglass anything — just to get into the zone.

Here is the canoe looking quite elegant in a sheer white number.

fiberglass on cedar strip canoe

And here is the job in progress.

wetting out the fiberglass

For this job, I tried to follow a few simple rules:

  1. Don’t dally when wetting out the boat.
  2. Don’t get hung up on one area. Move.
  3. Be in the goldilocks zone when removing excess resin. Don’t remove too little, don’t remove too much.

For once, finishing the bow and stern was quick and easy and devoid of the “what now?” deliberations that characterized previous builds. I trimmed back the excess glass as far as I could. While the ends were still wet, I applied a 2″ strip of bias-cut cloth (saved from trimming around the boat earlier) over the stems. Using a brush and gloved fingers, I applied more epoxy until the strip was completely wet-out. There are some wayward strands and a visible edge to the strip, but some careful sanding once everything is dry should blend it in.

Overall, the job went well. There are none of the air bubble problems that have plagued previous projects, nor does the canoe have an excessive number of drips.

I can’t wait to get the boat off the forms and upright.

Sanding and the sealer coat

February 28, 2011 § Leave a comment

Sanding is one of those things where it’s difficult to know when to stop. After all, how smooth is smooth enough?

Usually I get to the point of diminishing returns. In other words, continued sanding serves only to reveal gaps between strips and doesn’t add much in the way of smoothness. When I get to this point and the canoe is as smooth as it’s likely to get, I put the sander away for a while.

I should have mentioned something about the crack-filling process. There will be gaps between strips, either because of imperfections in the wood or a bad mating of strips. These gaps are easily filled with wood filler or a mixture of epoxy and sanding dust, mixed to the consistency of peanut butter. Wood filler (or plastic wood) tends to appear lighter than the surrounding wood when epoxied, while the epoxy/wood flour mixture tends to appear darker. While I’m glad that I didn’t use wood filler between strips, I should have used it to fill screw holes on the ash stems. Ash doesn’t darken as much as cedar under epoxy, and as a result, the epoxy mixture gave me dark dots on the stem. Live and learn.

When the sanding was done (or rather, when I was done sanding), I put a sealer coat on the canoe. The sealer coat is optional, but I like doing it. For one, it allows the wood to absorb epoxy so that it doesn’t absorb as much when the fiberglass is applied. The sealer coat also gives you a great idea of what the canoe will look like when it is glassed.

And here is a pic of the completed hull.

Next step: fiberglassing.


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