Part lll – Working with Epoxy
Early on I had decided that the process of rebuilding the gunwales would not include screws, bolts, or other mechanical fasteners. The main reason for this was that the original ribs had decayed in numerous places. In fact, in places, the ribs no longer extended up high enough to reach the sheer line. In other places, the wood was quite tired. It seemed unlikely that the ribs would be able to support the force of a screw fastened to hold the new wood in place.
I did decide that there would be 3 parts of the gunwale, an outside rub rail, an inside sheer “plank” and a top toe cap that would unify the structure. I wanted the new gunwale to add stability to the canoe’s aging frame, to reinforce any areas that were in need of additional support, and of course to act as an anchor to the seats and amidships support – all of which are necessary to keep the canoe from literally springing apart.
I did collect a good number of the old brass bolts and screws that I had previously used, 30 years ago. I went into my garage, looked around, and spotted a nearly full gallon of epoxy resin, with several partially used quarts of hardeners, one for cool weather and two for warmer weather.
Before “gluing up” the first strip of pine, I lightly sanded the outside area where the new wood would be in contact with the old fiberglass cloth. The outside skin of the canoe was in remarkably good condition. The fiberglass job that I had done 30 years ago had held up very well. When I had taken possession of the old canoe back then, I had decided that a nice thin layer of cloth over the old wooden frame would take care of the issue of some cracked ribs, as well as the burned out planking which was the result of a fire. Thirty years ago, the canoe was in worse shape than simply needing new gunwales.
Working with epoxy, and working alone can be tricky in terms of time and fastening. The last thing I wanted was to have a quick set. Once the epoxy starts to “go” that’s the end. If the wood is not clamped in place before the epoxy starts to set, the result will be a big mess! For that reason, I decided to do only eight to ten feet at a time, at least until I felt comfortable with the process. Before mixing any epoxy, I made a trial setting, with all of the clamps in place, and the scarf joints cut on both pieces. Since the canoe is almost 18 feet along the sheer, buying my pine in ten foot lengths worked out well. I used a 45-degree bevel cut that sliced across the two boards, overlapping them about six inches.
Once everything looked good, I removed the clamps, set down the wood, and mixed the epoxy. I found that six ounces of epoxy with one ounce of hardener was about all that was needed, I mixed in some micro balloons to get a nice pasty mixture, I mixed in some that were designed for fasteners, with others that were designed for feathering. I didn’t want the epoxy to go running down the side of the canoe. I used a thin piece of wood and a wide putty knife to apply the epoxy mixture to the side of the hull and to the new wood. I made sure to place the mixture wherever there was a rib, and often in between as well.