Once the canvas has been stretched on to the canoe hull, it needs to be filled. This fills the weave and waterproofs the exterior, making a smooth surface for the final coats of paint. To say that there’s lots of different canvas-filling options out there, and opinions to go along with them, is a bit of an understatement. Traditional oil-based fillers can be obtained from The Buckhorn Canoe Company in Canada and Island Falls Canoe in the US, among others. The good folks at the Wooden Canoe Heritage Association have collected a whole bunch of recipes for various fillers if you’d like to try mixing your own. Mike Elliot, who writes the Canoeguy’s Blog in British Columbia, now uses a latex pipe-lagging compound, and there’s probably more possibilities still waiting to be discovered.
I’ve used traditional linseed oil and silica fillers before, but this time I thought I would try something new. Dick Persson at the Buckhorn Canoe Company has been experimenting with using epoxy as a filler for wood-canvas canoes. It’s readily available, dries fast and is durable. So, I took Clementine up to his shop one Saturday morning.
This job was done with WEST system, but there’s no reason why it wouldn’t work just as well with any other epoxy product. You’ll need resin, hardener and a lightweight micro-balloon fairing compound, in this case WEST 410.
The first coat is un-thickened resin, poured on and distributed with a squeegee. The goal is to work it into the canvas and distribute it evenly but not leave excess on the surface. One difference that Dick has found with epoxy over conventional fillers is that you shouldn’t scorch the nap off the canvas first, since this hardens the surface and prevents the epoxy from penetrating through. Remember too that this filling method is being used on a hull whose outer surface has received several coats of varnish and mould-release to prevent it sticking.
We went from one end of the canoe to the other, pouring it on, working it in and then scraping off the excess. At the end of the first coat, we went back and hot-coated a second layer. This is a job for old clothes and old shoes, and also a good day to leave the dog at home, since the epoxy gets all over the floor around the canoe as it drips off the hull. After giving the two coats of clear resin about half an hour to dry, it was time for the fairing filler.
The filler is added and mixed until it’s the consistency of heavy syrup [or thin yoghourt, if you prefer], and then it too is applied by squeegee. After several sticky hours, you end up with a hull that looks like this: