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Posts Tagged ‘re-canvassing’

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.

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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.

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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.

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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.

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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:

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With three good coats of varnish built up on the outside of the hull, it was time to stretch the canvas. On final precaution against the epoxy filler adhering was to spray the varnished hull exterior with a hefty coat of silicone mould release. If you do this, just remember that you’re also covering the floor around the canoe with slippery overspray and you’ll need to tread carefully until it wears off! (says the voice of experience).

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The canvas is good old #10 cotton duck. For a canoe that will really see heavy service, you could go down to #8, but the heavier grade adds weight. At about 85 lbs, Clementine doesn’t really need to get any heavier. There’s a fair bit of information out there about canvassing and re-canvassing wood/canvas canoes, including The Wood and Canvas Canoe: A Complete Guide to its History, Construction, Restoration, and Maintenance by Rollin Thurlow and Jerry Stelmok, now sadly out of print, and of course videos on YouTube like this one.

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There are different schools of thought about how to stretch the canvas: right side up or upside down, tacks or staples. Personally, I’m a right side up, tack man. It doesn’t really matter in the end, because anything that will stretch the canvas tight and secure it to the canoe will do the job. I’ve even done it outside between two trees using a small child to help weight the boat down. When the canvas is folded in half and stretched tight, the canoe hull is inserted and forced down into the envelope. Here, I’ve got sandbags in both ends and two shore poles pushing down from the ceiling. You want to get it good and tight.

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Working out from the middle, the canvas is pulled up tight to the gunwale with a pair of wide-jaw vise grips or artist’s canvas pliers and tacked into place at each rib. With two people, you can work both sides at once. Here, my colleague Jeremy Ward is clamping the vise grips for another upward pull. The sign of a good job with the right tension is to have little “eyebrows” of puckered canvas above each pair of tacks when the pliers are released.

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As you go towards the ends, it gets harder and harder to pull the canvas in towards the hull, usually somewhere around the ends of the decks. When everything is tacked but the two ends, it’s time to cut the canvas away from the stretching clamps.

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Then, bit by bit, the ends and pulled tight and tacked. It’s not as hard as it seems to get the wrinkles out here, even on a hull like this one that has some hollow in the ends. By pulling on the bias, and occasionally removing and re-tacking some of the earlier fastenings, it will all come right eventually.

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With one side tacked in place, the canvas is cut close to the tack line and the process is repeated with the other side folded over the first. Some people like to add a little glue to help hold the ends in place, but be careful not to add too much as it may affect the adhesion of the filler later on.

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Next it’s on to the filler.

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On January 20th, 1937, my 17′ Old Town HW-model canoe was canvassed at the factory in Old Town, ME. On April 28th, 2013, I decided that at 76 years and 14 weeks I had probably gotten my money’s worth out of that first canvas skin (which I hadn’t paid for anyways!), and so it was time to re-canvas. A couple of years ago, I wrote about finding the canoe and making the decision to try and revive the original canvas instead of replacing it. Turns out to have been a good strategy, and it gave me many miles of paddling and sailing. It also helped me name my new canoe. The salvage job on the original canvas had left the canoe with a rather, shall we say, “textured” look, and this, combined with the Princeton Orange colour led inevitably to the name Clementine.

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The first step was to get the hardware, outwales, keel and old canvas off. The spruce outwales were held on with the original slot-head brass screws, and they were pretty well secured in their countersunk holes by years of varnish buildup. I’m always reluctant to use a slot bit with an electric driver because it’s so easy to have the bit walk out of the slot if it’s at all out of alignment, so I turned to a tried and trusted method for removing the outwale screws.

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With a simple socket attachment that takes standard 1/4″ hex shank bits, your brace and bit can be converted into a high-torque, low-speed screwdriver that’s very useful in situations where you have to proceed carefully but also apply considerable force. You do own a brace and bit, don’t you? The attachment is available from Lee Valley tools, among other retailers, for under $12.00. There’s also one for sockets which is very useful for freeing stuck nuts and bolts. I never cease to wonderat how surprised people can be to see simple, non-powered tools in use. A typical comment in this case was “don’t remember the last time I saw someone using one of those.”

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After the outwales were off, I removed the rest of the hardware, including the bolts that held the external keel on and the stembands. The stembands are the original bronze and I’m hoping to re-use them, so they were labelled and stored.

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Then, it was time to peel the canvas. I was pleased to find that the planking was in excellent shape and that there were no hidden pockets of rot. Traditional canvas filler can take more than a month to dry after it is applied. Because I was foolish enough to embark on a re-canvassing project at the beginning of the boating season and not the end, I was hoping to find a quicker alternative. My friend Dick Persson, proprietor of the Buckhorn Canoe Company, has been using an epoxy-based filler that dries in days, and not weeks or months, so I decided to use that. Epoxy is know for being rather sticky, so I needed to take an additional step before putting the new canvas on.

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I sanded the exterior of the hull with 80-grit to take out the re-saw marks and then built up three coats of varnish, topped with a healthy spray of silicone mould-release. In the event that any of the epoxy penetrated all the way through the canvas, this would prevent the canvas from becoming glued to the hull. I may not be around for the next re-canvassing, particularly if it’s another 76 years away, but it’s always good to plan ahead.

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To be continued.

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