Preparing and Fiberglassing the Interior

The process of fiberglassing the interior of the hull is very similar to what was done on the exterior but a few of the steps are very different. Planing and sanding the exterior planks is much easier and when the hull is completed, the exterior is generally fairer than the interior. When planking the hull, I always try to justify the planks so that the interior will need a minimum amount of work even if it results in the exterior being a little rough (which can be easily remedied).

Hours (and hours) are spent scraping and sanding the interior to get everything just right. Fairing the interior is much more difficult than fairing the exterior.

Before fiberglassing, a fillet must be formed around the lower part of each stem. This fillet has two purposes. It will add strength to the part of the hull that takes the most abuse and also gives the fiberglass a surface it can conform to.

This photo shows the make-up of the stem. Outer stem, inner stem, fillet on each side for the interior fiberglass strip to lie on.

The fiberglass is carefully laid out and fitted to the curvaceous interior. Much care is taken to do this without snagging the fiberglass on trimmed exterior fiberglass along the gunwales.

We avoid distorting the fibers by using a four-inch wide, soft bristled paintbrush to conform the fiberglass to the hull and to smooth out the wrinkles. Some snags and imperfections are inevitable but can be worked out using a small pick and a stiff bristled brush (i.e. toothbrush). Sunlight on the finished boat will show these flaws if not taken care of now.

The fiberglass is difficult to work into the stems, so we do this in several stages. First, a three-inch strip is wetted out down the center of the stem. Then, fiberglass pieces about 18 inches long are wetted out on each side of the stem (overlapping the three inch strip). Then the main piece of fiberglass is fitted and trimmed so that it overlaps the 18 inch pieces. This method is much, much easier than trying to do it all in one piece.

Finally, the main section is wetted out. Two or three more coats of epoxy will follow this.

Fiberglassing the Outer Hull

The fiberglass is laid out on the hull and trimmed so that there is about six inches of overhang at each end.

Much care must be taken in smoothing out the fiberglass. It is very easy to misshape or snag the fiberglass fibers which can result in a blemish in the final product. We use a wide paintbrush to work out the wrinkles. With some effort, you can get the fiberglass to conform to the ever-changing curves and bevels of the hull.

The fiberglass is then wetted out with epoxy. After it has been saturated, the excess epoxy is squeegeed out.

A second coat of epoxy is applied to fill the weave followed by one or two more coats of epoxy once each prior coat has semi-cured. The final coats of epoxy are applied to build up enough thickness so that the hull can be sanded to its final smooth finish without exposing the fiberglass fibers.

Once the final coats of epoxy have cured, the excess fiberglass is trimmed from the hull. After curing for a day, the canoe will be removed from the forms so we can begin smoothing the interior.

Prepping the Hull for Fiberglassing

After planing the outer stems into shape, many hours are spent preparing the hull for fiberglassing. At the beginning of this stage, the hull is a series of edge glued rectangular planks and is fairly rough. The goal is to transform the hull, with all of its hard edges, into a smoothly curved, free flowing shape.

Fairing the hull is accomplished by first methodically planing the seams of the planks. For me, planing is one of the most enjoyable steps of the building process. I like it because you can see immediate results and I know that it is saving me a few hours of sanding.

After the hull has been planed, the sanding begins. It takes many hours of sanding to get things just right. Sanding is hard work and after several hours, becomes somewhat tedious. If planing is one of the most enjoyable steps, then sanding is one of the least. It is, however, the most critical step in determining the final shape of the canoe and much care must be taken to get everything just right.

After all of the highs, lows, and wobbles have been sanded out of the hull, the final step is to "raise the grain". Raising the grain is accomplished be wetting the hull down with water which swells the wood fibers. After the hull has dried, the raised fibers are given a final sanding with fine sand paper. This step will keep the grain from rising when the fiberglass and epoxy are applied. The wet hull gives us a preview of what the wood is going to eventually look like.