re-canvas question

[patrick corry]

I'm recanvassing an Island Falls 15. It's my first time canvassing a canoe. I have the canoe in the canvas "envelope", the canvas is nicely stretched, the canoe has approximately 150# of weight distributed evenly (there's no ceiling from which to mount shores to push the canoe into the canvas).

The canvas is nicely taut everywhere with the exception of just behind both stems. Where the canvas departs from the stems the canvas has no wrinkles. From the base of the stems, and extending about 36" along the bottom, there is a ridge of canvas held away from the planking by about 1/2" and tapering to zero at each end. In the accompanying photo you will see it within the box I've drawn onto the photo.

I'm assuming that once I've attached the canvas to the point where the "ridge" of canvas begins, I can slightly relax the come-along enough to allow me to pull the canvas up to the gunwale sufficiently to remove these ridges. The thoughts of veteran canvassers will be appreciated. Thanks.

 

[Fitz]

I am an upside down type of guy, but first off I would suggest longer clothes pins. They should extend the width of the canvas envelope. I use pieces of clamped 1x or 2x4's and snug them up to the face of the stems.

When you start attaching the canvas to the rail, start in the middle of the canoe and alternate sides and go toward both ends. Only go as far as about the edge of the decks before taking it off the stretcher. You can also use some "cheater" staples in the side of the hull in that area to pull the canvas tight to the planking while you secure the stems and the rest of the rails beyond the edge of the deck. Pull the cheaters out when you are done. I think you are right in that by the time you pull the canvas tight beyond the edge of the deck, the pucker will disappear.

Keep us posted.

Fitz

 

[patrick corry]

Thanks Fitz for your reply.

The device you are seeing is actually a different sort of "clothespin" I made from two woodworking shims & a spring clamp, whose purpose is to consistently mark the canvas 4" above the rip tops.

In this picture you can see better how it works... the shim tips are aligned, the "clothespin" is split by the excess canvas so that on one side the clothespin touches the rib top while the outside portion has a 4" mark on it, which is then transferred to the canvas. You can see the darker portion (the hull) and the somewhat translucent excess canvas above.

In my first photo you can see the line of black marks on which I will cut the canvas as I progress from the center out to the stems. I did install proper clothespins at each stem, several inches beyond the stem. The canvas is laying very nicely everywhere but the two small 'ridges' I described. I did fasten about 8 ribs on each side at the center so far... and will probably continue tomorrow after another 24 hrs. of 'stretching & relaxing' time in the canvas.

 

[Howie]

Before you proceed I would recommend trimming away the excess canvas that's above the rails. Doing so will allow the canvas to drape easily around the canoe. Trim off to maybe 1" or 2" above the rails.

Now this may be controversial, but after letting the canvas hang under tension for a few hours I back off on the tension to where I can pull 'up' the canvas along side the decks and cause the canvas to lie against the hull. If the canvas is too tight you won't be able to do this with canoes that have decks with concave sides (like OT Otca, Yankee, HW, etc). Then proceed to pull the sides 'up' with canvas pliers & staple as Fitz described. Before you cut the canvas free add the cheater staples on both sides of the stems so that the tension is retained once the canoe hangs free. Then staple the stem area starting by the decks & working down, removing the cheater staples as you go. Hint: before stapling the stems place your stem bands against the side of the canoe & mark the canvas with pencil where it's screw holes will lie. Avoid stapling in the center of the stem in these areas as it's hard to drill screw holes through stainless staples!

 

[patrick corry]

Thanks Howie for your thoughts.

So... like most things in life, overthinking the process leads to a lot of the "what if" thinking. I was/am probably too cautious, but now that I'm well into the process it's proceeding just fine! First photo shows the canoe in the canvas, clothespins in place, weight in the canoe distributed by the 1x12 board across the entire length of the canoe.

Next, stapling proceeds. I cut the canvas down to the 4" line and I found that my canvas clamps (actually Vise grips with wide jaws that I use for standing seam roofing) seems to grip a doubled-over canvas without tearing at the corners of the jaws better than a single layer. Also, I was too nervous about trimming the canvas too short!

Once I reached a point midway between the quarter thwarts and the decks (which are tiny on this canoe), I slackened the come-along by about three "clicks", which allowed me to easily pull up the wrinkle/ridge behind the stems; just as Howie predicted. At this point I need to continue trimming canvas and I'm nearly at the point to release her from the tensioning rig.

The black marks on the canvas indicate the ribs which will receive the original outwales. I didn't want to put a staple in the way of the screw holes, so I was careful to avoid placing them in the center of those ribs which get the outwale screws.

 

[Dave Wermuth]

Once you're within 2 foot of the end you can take the clamps off and finish it. I staple the last two feet of gunnels after I fasten the stems. That gets the canvas tight to the hollow part of the hull. Works for me.

 

[patrick corry]

It went well! All stretched, stapled, and stems overlapped.

There's some "character" in the hull... a few imperfect surfaces, un-fair curves, etc. but overall of the elements I could control no problems. Now, on to filling with traditional filler then the long wait for curing!

Note on the first and second pictures, the pencil marks indicate the stem band screw locations. Thanks Howie, and thanks all for 'watching' and commenting.

 

[lowangle al]

Looking good Patrick, your moving right along.

 

[patrick corry]

New question...

Since my last post I have filled, sanded, primed & sanded two coats, and finally first coated with color (Kirby's Grayling Gray). After the next coat of color I will cut down the canvas to the top of the planking which is pretty accurately 1/4" below the rib tops. My question is this; having stapled the canvas during the stretching process, which of course imparts some significant stress to the canvas causing the typical puckers at each rib location, will cutting the filled/painted canvas so close to the staples allow that stress to tear the canvas at the staples?

My thinking is that the canvas now is a semi-rigid 'shell' due to the filler and subsequent coats of paint, and that the stress is limited since the canvas is now encapsulated by the filler/paint. In the accompanying photos the upper solid line is the top of the planking derived from a jig which rests on rib tops and a lower leg which is 1/4" lower for marking purposes. The lower- dashed mark- at each rib- marks the lower edge of the outwale to be re-installed. Don't worry, this mark will be covered by paint before the outwales go on. There is enough room between the line and the dashes to place additional staples BEFORE I cut the canvas.

Is this advisable? Necessary? Am I overthinking again...

Thanks, Pat

 

[Michael Grace]

There shouldn’t be any need for additional staples. You canvas has sat there for a long time getting comfortable on the canoe, and you have filled it. I wouldn’t describe the canvas as semi-rigid, but it should be settled into its shape, plus each individual staple is in the hull perpendicular to tension and is taking only a portion of any overall tension. There’s no reason to suspect that staples would pull loose when you trim the canvas short. If that were likely to happen, they would’ve pulled loose already. In other words, shortening the canvas should have no effect, and in my experience, staples or tacks have never come loose at this (or any other) stage.

 

[Howie]

Yup, I agree with Michael. But that being said I find that I'm sometimes guilty of pulling the canvas too tight on the sides which can cause the canvas to bunch-up behind the staple. If I fear this bunch-up will impact how close the outer rail will lie against the canoe sides I'll take some pliers and pull the canvas 'up' to try & lessen this bunch-up. If I'm not happy with the result I've been known to add a staple a bit below the existing one, remove the staple above, then trim away the 'bunch-up' with a knife or razor. Just so long as the new staple must be covered by the outer rail.

 

[patrick corry]

Thanks for your thoughts.

I don't anticipate that the staples might pull out, rather, that the canvas once cut will only have a few threads above the staples and therefore may be weak and will allow the fabric tear, thus loosening the overall tension of the skin. I think perhaps a close inspection may reveal that where the cut line is too close to a staple (or staples) I will add the occasional new staple in the space between the cut line and the lower limit of the outwale.

Howie, I had the same thought about the bunch-up, or what I call the 'pucker'. On this canoe the pucker is still flexible and I'm relatively sure the outwale screws will successfully flatten the pucker sufficiently to allow the outwale to snug up against the rib tops.

The other consideration is that all the outwale screws will be piercing the canvas skin on every other rib the full length of the canoe. This will undoubtedly add to the attachment of the skin, aiding the staples in holding whatever tension may exist.

Signed, "The Overthinker"

 

[Howie]

Yeah... about your screws piercing the canvas. Sometimes I've found that when the outer rail screws 'pierce' the canvas the twisting motion of the screws can cause the canvas to buckle below the rails a bit and cause a bump. So watch out. If this happens try backing the screw out entirely and flatten the canvas so it lies against the canoe body once again. Then use a c-clamp to hold the rail firmly against the body of the canoe and tighten the screw again. Or better yet, use a c-clamp to hold the rails for each screws. O - and maybe get some screw wax to make the screws go in easier.

 

[Michael Grace]

I misunderstood your question Patrick. I agree that you don’t want your staples too close to the edge of the canvas, but a quarter of an inch might be fine to normal. I don’t really think about it anymore, just do it, so I’ll bet that mine tend to be a quarter of an inch or so from the edge of the canvas after trimming.

How he makes a great point about those puckers above the staples. You don’t want them to be too extreme.

 

[Rollin Thurlow]

Howie,
I bet the buckle in the canvas is not caused by the screws but the canvas being cut just bit too high above the planking line. When the outside rail is put on, the rabbit of the rail is pushing down on the little bit of extra canvas, causing the buckle. Either way the solution is the same, just as you stated.
For me , there is no such thing as too much of of a pucker. I've had problems from not pulling tight enough but never from pulling too much (well until the canvas tears!). As far as I'm concerned, the pucker is my friend!

 

[John Janicek]

I've really enjoyed this thread. I do have a question though as I'm getting close to canvassing the 16' OT I'm working on. What is the preference for fastening the stretched canvas? Is it SS staples or brass tacks (and if tacks is it 1 or 2 tacks at each rib)? I'm guessing that it doesn't really matter as long as the fasteners are secure. Thanks.

 

[Michael Grace]

My experience is the same as Rollin's. Maybe the twisting of a screw could cause a buckle, a kind of blebbing out of the canvas just below the rail, but every time I've seen it happen it was because the canvas was cut a little too high and the outwale pressed down on the filler-stiffened canvas. It's easily corrected by trimming down the canvas a little lower.

John - traditional is two brass tacks per rib, although different things were done depending on maker and year. For example, later Old Towns utilized very narrow but long-legged staples. Personally, long ago I went to stainless or Monel staples, one per rib. You might prefer closing up at the stems with small copper tacks, or use Patrick's method of marking where screws will go and not putting staples there, because it's unpleasant to hit a Monel or SS staple with a drill bit when applying outside stems or stem bands.

 

[John Janicek]

Michael - Thank you for the reply. I like the idea of using staples. I'm thinking that the staples' crown would provide more support/grip to the canvas at the point of fastening than two separate tacks would. Fortunately, I was just about to purchase more brass tacks for the canvassing effort but now I'll think I'll switch to monel staples instead. I've already purchased copper tacks for the stem. I did take note of Patrick's method of marking where the screws will go and will surely employ using it when I'm at that point. I assume a 1/2" staple would be sufficient to do the job?

 

[John Janicek]

I forgot to ask. Do you use a standard T50 size staple or is it a different size with a wider crown between the points?

 

[Dave Osborn]

I use stainless T50 staples 1/2” for ribs and stems. Two per rib.