Eva Too

These folks look experienced with the glue part of stitch-n-glue boatbuilding.

It’s time to fully fill the seams with thickened epoxy and add fiberglass tape for strength. As an aside, the “tape” is simply fiberglass fabric that is 4 inches wide, finished on each edge to avoid fraying. Filling the seams is the same as I did with “tabbing” in the previous post, spreading thickened epoxy with a rounded stick about 1 inch wide. Affixing the tape is with unthickened epoxy, regular stuff that’s slightly less viscous than molasses. CLC’s instructions suggest painting on a coat of epoxy, pressing the cloth in place, and then painting on more epoxy to saturate the cloth. Another fellow I read suggests soaking the cloth strip in epoxy to saturate it, then placing it in the boat and spreading out the excess with a gloved hand.

I tried both ways, always with gloves. Both methods work, but one feels like you’re retrieving your waffle from a vat of syrup chocolate.

The interior of this boat will get no more fiberglass. A few people glass both the exterior and interior of their boats. I think those are the people who don’t mind the extra weight and want the extra strength for extreme canoeing adventures. This boat will get two very thin coats of epoxy as a sealer. Another finish will be added later for UV protection (epoxy has very little). The first coat is on, applied with a short nap foam roller which really spreads the epoxy thin, helping minimize weight.

Would you like to see a picture of the stitches in my arm? No, I didn’t think so. Actually, they are almost gone, the self-dissolving kind left from a very minor surgery some time ago.

Some stitch-n-glue builders leave the stitches in the boat. They cover the seams with a thick fillet of epoxy, then epoxy soaked fiberglass cloth, all in one pass. One might follow this approach for either of two reasons, to get a good solid seam by applying everything at once, or to build the boat quickly (Build a boat in a week!). Once the epoxy sets around the wires, they’re there to stay. All that can be done is to snip the tails off on the outside, and deal with the detritus in all the rest of the finishing steps.

The more persnickety builders do the seams in two steps. The first is “tabbing,” securing the spaces between the wires with thin epoxy fillets. Then the wires can be removed and the full length of the seams reinforced. Guess which camp I’m in. Right! Persickety. You win today’s prize.

Even this, I did in two stages. I mixed epoxy straight out of the pumps with no fillers. I brushed this onto the seams to allow the raw edges to soak up some glue. Then, I mixed in “wood flour” to thicken the epoxy to a consistency midway between mustard (Dijon, not yellow) and peanut butter.  I pressed that into the seams fairing them with a rounded stick (think tongue depressor). I was persnickety about making these extra clean so they won’t need sanding before the cloth layer.

Denatured alcohol (not the drinkable kind) is a good clean up agent for removing epoxy from places it does not belong, such as the handles of my pliers and clamps. Recent reading suggested trying simple white vinegar. Dang! It works better than alcohol. It’s pretty amazing that the stuff we splash on our veggies can remove rust from tools and cut this industrial adhesive. Or, maybe it’s amazing that our digestive pipes handle the solvent?

Well, I won’t be completing this boat in a week, but it will end up prettier than my arm.

The stems of most boats are designed to take the abuse of collision, accidental of course, and are often made of hardwood, oak, ash, or something similar. The ends of these stitch-n-glue boats are not hardwood, but simply the join of two 3/16″ thick pieces of plywood. They are made stronger by the addition of fiberglass cloth and by an “end pour” of epoxy resin. The “end pour” can be done by standing boat on end and pouring a puddle of epoxy resin about an inch deep into the end of the boat. While I know that hundreds of these boats have been built that way, it does not appeal to me. I would rather reinforce that area with the traditional material, wood. Well fitted, it will be just as durable, maybe more shock absorbent, and certainly much lighter.

My wooden stem fillers are made from spruce retrieved from the (good lumber) cutoffs pile. Shaping them now before the hull is glued closed makes it easy to get them right. They’ll be glued in place after initial hull glue-up.

As always, click on the photo for a larger version.