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Why do we still use cotton to cover?

Discussion in 'Wood and Canvas' started by jlraley, Feb 3, 2015.

  1. jlraley

    jlraley Curious about Wooden Canoes

    I'm researching my first canvas wood repair/restore project, and I'm curious why we still use canvas to cover them? I'm coming from the skin kayak world, where we use ballistic nylon or polyester because of their strength and longevity. Cotton is actually no longer seen as a viable option, because it costs more, is more susceptible to rot, tears much easier, and ends up weighing more due to absorbing so much of the filler.

    Do we still use cotton on these to be authentic, or is there a practical reason? I suppose nylon stretches when wet, so that could be an issue on a wood/canvas canoe? Polyester seems like it would be ideal though, especially since it can be heat shrunk on with an iron.

    Please educate me!

    John
     
  2. Andre Cloutier

    Andre Cloutier Firestarter. Wicked Firestarter.

    With respect, you cant have read much before asking this. There are virtually no similarities between a cedar canvas canoe or boat and a skin on frame craft. While it is undeniably traditional, it has been shown to be the best overall covering due to many characteristics and properties. While the canoes it covers are anachronisms, like most of the building methods and materials used if there were better ways to go about it, they would have evolved. Oh wait, i'm describing Kevlar. Its like the difference between a machine gun and a muzzleloader. Sure you could begin to evolve a muzzleloader with modern methods and materials but you'd end up with the machine gun, and likely thats not what you are looking for.
     
  3. Benson Gray

    Benson Gray Canoe History Enthusiast Staff Member

    Tradition is the short answer as Andre suggested. The practical reason is that filled canvas is both surprising durable and relatively easy to replace or repair. Many other materials have been used and they offer a variety of different strengths and weaknesses. Dacron is very light but is prone to pulls and tears. Fiberglass with resin is durable but not easily removed. Most canoes are typically heavier and larger than skin on frame kayaks so they generally need to be able to take more abuse. Others may be able to offer better explanations,

    Benson
     
  4. OP
    OP
    jlraley

    jlraley Curious about Wooden Canoes

    Andre,

    I am sorry if I have offended, but I am not sure how. I in fact stated that I was researching my first wood canvas canoe restoration. My research to date has been limited. I'm still waiting on the Wood Canvas Canoe book, and maybe that contains my answers. Otherwise all I have found is mention that some builder's and restorer's in fact do use polyester, and also use more modern fillers. This includes the silica/oil alkyd fillers as a newer filler, because who would still use lead when a safer option exists?

    Your reply does not actually answer my question. Why has canvas "been shown to be the best overall covering due to many characteristics and properties"? I have not found that anywhere. Since it is a replaceable part of the boat expected to wear out I doubt it's because it's purely traditional.

    I'm not sure where a kevlar boat that uses completely different and modern building techniques compares to skin on frame construction using techniques older than wood canvas canoes? Frankly I build skin-on-frame kayaks because I love the anachronism. This is why I am going to rebuild and restore this canoe being gifted to me. The wood canvas canoes that I have paddled have given me far greater joy than the fiberglass Algonquin Winisk's I typically use to lead trips.

    Modern anachronistic recreations of skin on frame kayaks do not use seal skin both because of the ethics involved, and because its not an efficient material when compared to Ballistic Nylon. Why do we still use canvas as a temporary replaceable material on wood canvas canoes instead of modern materials?

    Respectfully,

    John
     
  5. OP
    OP
    jlraley

    jlraley Curious about Wooden Canoes

    Thank you Benson,

    My research has shown the same issue with Dacron, and I would never ever cover something that could be considered an antique with the epoxy resin that fiberglass requires. If tradition is the answer I am happy with that. If it is some other property of canvas and how it acts when covering a cedar canoe vs modern comparable fabrics I am very curious to know what those properties are for my own education.

    Thank you very much for the reply,

    John
     
  6. MGC

    MGC Scrapmaker

    Both good answers (Andre, Benson).
    Canvas is surprisingly tough, it is easily repaired or replaced and when properly cared for can last for a very long time.
    I have old and newer canoes. Some I use in rapids and some are paddled purely for the pleasure of using them.
    My "daily driver 1916/17 canoe. It is not a closet queen. It gets used for canoe camping and fishing.
    Simply put, canvas works perfectly for an exterior skin. It has been proven for 115+ years.

    It has been said here before but it is worth mentioning again, a canvassed cedar canoe has a very pleasant "feel" when you paddle it. No other canoe has that same ride/paddle quality, not even an nice all wood canoe. Once you paddle enough canoes, you'll get it.

    I contrast wood and canvas canoes to steel framed bicycles. Cycles made of carbon fiber, aluminum, titanium are lighter, stiffer, faster but they do not offer the riding pleasure or comfort of steel. Yet steel is considered by many to be an anachronism, a throwback technology. I'll take my steel frame and a wood and canvas canoe all day long over my Kevlar canoe and titanium bike....
     
  7. Kathryn Klos

    Kathryn Klos squirrel whisperer

    Hi John-- and welcome!

    Historically, the canoe builders wanted to produce a "carriage finish"-- a hard surface that could be painted and (sometimes) decorated with pinstripe designs-- a covering that would stand up to a fair amount of use and abuse that could be easily patched and replaced. In the 100-plus years that these canoes have been around, builders have tried other materials for covering the wooden hull of a canoe and nothing has worked as well as canvas. Whether it "works" has to do with aesthetics as well as function.

    Some canoes retain a very old canvas covering that is still in usable shape, so the word "temporary" doesn't seem to apply... "replaceable" does, however. Maybe if canvas only lasted five years or so, I'd be inclined to think there was something better... but knowing the canvas on the canoe I am having restored this year will last longer than I will has me feeling more temporary than the covering on my old Morris.

    Maybe it's that I simply don't know much about other materials. Can ballistic nylon be given a coating of filler that will become rock-hard? Could it then be painted my choice of colors? Given the fact that I paddle quiet waters, would it last 20 years or more?

    These discussions are always welcome here. We learn from each other.

    Kathy
     
  8. Andre Cloutier

    Andre Cloutier Firestarter. Wicked Firestarter.

    No one is offended, but you'll benefit from a lot more reading about canvas covered canoes. Ethics debates arent desirable either, seals are a renewable resource whereas nylon, kevlar and most petroleum based products are harmful both in extraction and production, through to their eventually being disposed of, hence the Pacific garbage patch. In a quick, disposable society where longevity has been usurped by planned obsolescence, i'd say the answer to your question is about equal parts technology and nostalgia, tipped just a little towards technology and functionality. The materials evolved together to where they compliment one another. John Winters designs great boats, but the Kipawa was never intended for traditional construction, instead focusing on prismatic coefficiencies, stability and speed, not the kind of thing one who restores boats a century old cares much about. Enjoy learning about them, no doubt it will make sense by the time you start your own project
     
  9. Dave Osborn

    Dave Osborn LIFE MEMBER

    Welcome John!
    In addition to all of the qualities that have been stated, I'll add that canvas is forgiving, in that most vintage canoes are not totally fair. Try as we might to fair a hull perfectly during restoration, there are occasional tack heads that stick up proud, dents, plank edges and gaps, etc. that would telegraph through Dacron, and other more modern materials.
    The canvas, being thicker tends to bridge those gaps, dents, and structures and hide those anomalies.
     
  10. OP
    OP
    jlraley

    jlraley Curious about Wooden Canoes

    Thanks for all the replies. I did not mean to have a debate or sound like I'm advocating using a different material. I am just truly curious why they are not used.

    Just to give the back-story to how I arrived at this question: In researching wood canvas canoes you quickly run into the question of fillers. Skin on Frame builders first used spar varnish, and nowadays have moved onto highly toxic 2-part urethanes. I'm not a fan of these options for a variety of reasons and have settled on a particular acrylic roofing elastomeric that's highly durable, abrasion resistant, uv stable, and has minimal to no hydrocarbon/VOC off-gassing when drying, and minimal toxic solvents.

    When researching wood canvas canoes you quickly run into oil alkyd silica based fillers, or worse lead. I have health concerns with these, plus the addition hassle of finding a clean environment to allow a linseed oil/alkyd mix 3-6 weeks to cure. I began looking for other fillers that are deemed suitable, and discovered that several builders/restorers are using mastic fillers that are very similar to the one that I use on my skin on frame boats. I've actually chatted on a different forum with one of those builders.

    This lead me to wonder why if changing the filler does not change the properties of the boat significantly why do people still use canvas. The particular builder i'm referencing still uses canvas on his restoration projects.

    Ballistic nylon, and to a lesser degree heavy basket weave polyesters are far stronger than canvas, and significantly more puncture resistant. Typical 1050d Nylon requires 175lb of pressure applied to a point (like a screwdriver head) to puncture. Canvas requires something like 10lb of pressure.

    Nylon and polyester also have significantly longer lifespans if appropriately UV protected, and I figured that would reduce the necessity of regular recovering. What I've found so far seems to indicate that with canvas you should be prepared to recover every 10-15 years, but that it may last significantly longer.

    In my research to date I did find a few mentions of people trying dacron, and even some manufacturers using it, and it is considered inappropriate due to it's poor puncture and abrasion resistance. The same reason most home skin boat builders do not use it. I could not find anywhere that someone has tried ballistic nylon or heavy weight polyesters.

    This lead me to ask my question. Again I am not advocating the use of alternative materials, but was merely curious as to why they do not seem to be used. Is there some superior quality of canvas covering a wood hull, or is there some inferior quality of how nylon or polyester react?

    The general consensus from this thread seems to indicate that my questions don't have answers at this time. Canvas has worked perfectly well for 100+ years, so why even try a different material in those circumstances? If it's not broken why fix it? This seems like a totally legitimate argument even if it does not quell my scientific curiosity.

    Thanks for your responses.

    John
     
  11. JClearwater

    JClearwater Wooden Canoe Maniac

    John,

    If I had been the first to reply to your initial post I would have said the same as Dave did in his post #9 above. Dacron works well and will produce a good final result if the hull a perfectly smooth and fair. With a restoration, which is what you are looking at, despite your best efforts at fairing the hull, every little bump, planking edge, proud tack head etc. will telescope through the Dacron and be visible in the final product. Canvas is much more forgiving as Dave said. Dacron will be lighter for sure but the aesthetics will suffer to the point you may not be happy with the result. If you were working with a brand new hull Dacron would be a good option but with an old hull you are better off with canvas. Good luck with your project and please post some pictures.

    Jim
     
  12. Todd Bradshaw

    Todd Bradshaw Sailmaker

    I don't know where you're getting your figures, but based on nearly 40 years of working with all of these fibers, I don't believe some of them are accurate.

    You aren't going to puncture typical canoe canvas with a screwdriver and ten pounds of pressure - not even close, and when filled with traditional filler, it is even tougher. I once removed old canvas from a canoe and decided to see what it took to puncture and tear it. So, I took a big gutter nail about 12" long and tried it. It pretty well put any fear of ripping the canvas on a canoe to bed in normal use unless I hit something extremely sharp - especially considering that the canvas on a canoe is not suspended out in space, but is backed up everywhere by wood. The focus of such an impact seems more likely damage to the planking than the canvas.

    If you do a tongue tear test of similar weights of nylon, polyester (Dacron is polyester, by the way) and cotton canvas, the nylon will win, the cotton will be next and the polyester will come in last. This is due to the tearing properties of the three and their ability (or not) to stretch and for the fibers to give a bit and help reinforce their neighbors. Where the nylon and cotton will give a bit and spread the strain over multiple yarns, the polyester yarns tend to take the stress one by one and break. This is called explosive tearing and is why I can take a hunk of heavy polyester and easily tear it in half. This does not happen with nylon or cotton.

    Unlike skin-on-frame constructions, I think you also have to take the non-suspended nature into account which will limit the type of impact the cloth will typically be subjected to. Should you slam into a screwdriver with a wood canvas canoe, you will likely have more serious problems to worry about than the canvas.

    This would depend on what conditions the various fibers (and canoes) are subjected to. Cotton canvas does not self-destruct after 10-15 years all by itself, and we have certainly seen plenty of canoes where it has lasted far longer than that. Yes, it is the only one of the three where mold and mildew can actually eat the fibers, rather than just sitting there on top of them, but with mildewcide treated canvas these days, and the ability the boats seem to have to dry out between uses, this is less of a factor. You also should probably consider that the modern wood/canvas canoe usually leads a fairly pampered life. After going through all the work to restore one, or spending the cash to buy a new one, few people are going to beat it down a rocky stream, or store it out in the back yard on saw horses next to the Grumman.

    In terms of durability of the raw fabrics, for UV the polyester is best, cotton will be next and nylon will be the worst. For abrasion, the cotton is best, and it's a toss-up between the synthetics, depending on the weave. Cotton's somewhat fuzzy nature, because it is made from short fibers spun together, builds in a little bit of cushion which helps protect it. The synthetics with their continuous extruded fibers don't have this. Rock climbers found this out 40 years ago when they found that their new-fangled nylon assault packs were getting quickly abraded to death being dragged up the rocks. They quickly switched back to their old canvas packs. The good news about this was that it helped spawn the development of cordura nylon, which resists abrasion much better because it has a fuzzy surface. I suppose you could take samples of all three and test them with a belt sander to see which is toughest if you wear through your filler, but I haven't tried it. My suspicion is that the cotton will probably win.

    With solvent-based (like traditional) fillers, you will probably get a much better filler-to-canvas bond with cotton due to its drastically higher rate of absorption. In order to get a truly smooth surface with no weave texture for a classy paint job on the synthetics you would probably need an epoxy-based filler. Polyesters usually aren't very absorbent (like just a few percent of their weight) and nylon isn't a lot better. Epoxy is likely to stick much better to these than a traditional filler will.

    I suspect the best synthetic system might be something like heavy Oceanus polyester canvas sailcloth and an epoxy mixture to fill it, though it would rely on being able to stretch the Oceanus enough to get it tight (which may or may not happen) and using the right filler mixture. Most of the easily sanded epoxy mixes are too soft, and the ones that are similar in hardness to canoe filler are a real bear to sand smooth.

    On the other hand, I have no problem with sticking with real canvas and traditional filler because we know it works and because it's what was there originally.
     
  13. Greg Nolan

    Greg Nolan enthusiast

    Some thoughts and a question about the above:

    First -- Fabric stretched over solid planking is not the same as fabric stretched between widely-spaced stringers. Puncture resistance is much less of a concern for a fabric completely backed by a wood-planked hull than it is for fabric backed only intermittently by the thin wood strips of a SOF boat. The wood of a wood-canvas canoe provides the primary "puncture" resistance, and I suspect ballistic nylon would not provide substantially more protection than canvas in a "puncture" situation -- running into or on to a rock with such force that the canoe's planking and/or ribs are cracked. Ballistic nylon gets much of its puncture resistance from it's ability to flex and stretch, something that seemingly would not be of much use when covering material -- wood -- that has less flex and much less stretch.

    Second -- I understand that ballistic nylon stretches (actually, becomes loose even when no stretching force is applied) when wet. On a SOF hull, this would mean that the fabric become a bit less taut -- not much of an issue, I think, when the hydraulic pressure of the water in which the boat is floating would tend to keep the fabric smooth between stringers instead of wrinkling or sagging. But when the fabric covering a wooden planked hull gets loose, what happens? does it wrinkle? Does the looseness make snagging more likely in a situation where a taut fabric would slide past an obstruction?

    Third -- almost nobody is using lead in fillers today -- most people are aware of its dangers, and it is also hard to obtain. Synthetic material such as nylon are essentially processed petro-chemicals made from non-renewable resources. Cotton, of course, is renewable -- though I am aware that the agricultural practices used in growing it (pesticides, especially) may not be so benign.

    Just what is the roofing material you use? This past fall I recoated my flat roof in Brooklyn with an acrylic elastomeric compound (instead of tar) that seems fine as roofing, but is not something I would have even thought of as using as canvas filler -- when shoveling snow off it last week, it seemed a bit soft and rubbery (fine on the roof), and I am not sure what kind of a base it would provide for paint.
     
    Last edited: Feb 4, 2015
  14. divedog

    divedog LOVES Wooden Canoes

    I've built a couple skin on frame kayaks and one canoe. The canoe is covered with a 12 oz. (if I remember correctly) heavy polyester. The weave is very coarse, which I think would make it a real bear to suitably fill and smooth on a cedar-planked canoe. The kayaks I built were covered in #10 duck canvas and I think are more susceptible to damage (in an SOF application). However, filled and painted canvas, with the advantage of a cedar backing, create a surprisingly tough skin. I don't think that combination is vulnerable to the same kind of catastrophe an SOF is, such as a jagged rock making a long slice in the hull. My advice would be to try the traditional method first. If you don't like the results, it's easy to remove it. Good luck with your project and please keep us posted... I for one, love to see pictures!

    Mike Wootton - Spokane, WA
     
  15. Dave Osborn

    Dave Osborn LIFE MEMBER

    John,
    If you are looking for a quick drying alternative to traditional filler, sans lead and loaded with biocides, search Cecofil and Ekofill on the forum. It is a waterborne filler designed for the home-built aircraft guys that works well on canvas. A process for application is buried in a thread somewhere here.
     
  16. rpg51

    rpg51 Enthusiastic about Wooden Canoes

    There are some builders that will use Butyrate to fill the canvas. See Headwaters Canoes for example. The results are tougher and lighter than traditional filler and you can use a lighter weight canvas. The finish is not the same as the finish with normal filler. It has a matte appearance and texture. Very tough stuff. It is more expensive. Some folks like it. Others no.
     
  17. sam.p

    sam.p Enthusiastic about Wooden Canoes

    why use canvas.

    Tradition. They are wood and canvas canoes.

    Cordially,
    Sam
     
  18. sn8886

    sn8886 Curious about Wooden Canoes

    Hi John,
    I have questions similar to yours but probably less informed by experience. A couple of years ago I discovered I have a (wood-canvas) Morris canoe, estimated by WCHA to be built in 1912, that I have owned since 1970. My canoe had / has 20+ cracked or broken ribs in it's original un-restored hull. 45 years ago I covered it with fiberglass cloth and polyester resin that has kept it together for all these years. It's not going to win any beauty contests but it is functional. When I recover my canoe I will consider alternatives to canvas. My point here is that modern composites can add structure while a canvas cover relies entirely on the integrity and strength of the wooden hull. New wood is flexible and supple, old wood becomes dry and brittle. I'm getting a little old and crumply myself, but try to keep my thinking modern. My Morris is a pretty as the next...from about 20 feet away.
     
  19. Paul Fopeano

    Paul Fopeano INNKEEPER

    I have seen some beautifully finished dacron skins on old wooden canoes and in the right hands really look nice! I have also epoxied a hull or two when it seemed proper at the time. If you really want to find out why some still do the cotton canvas thing visit a popular canoeing area and just listen.... You will not hear much when a wood and canvas passes bye. You will not hear much when a fishing lure gets dropped or when a gunwale get tapped by a paddle. It is a beautiful thing to be so quiet!
     
  20. sn8886

    sn8886 Curious about Wooden Canoes

    I've never experiienced a cotton canvas cover

    I've never experienced a cotton canvas covered canoe. I bought one but immediately covered it with glass fiber and polyester resin. Maybe this is a compelling reason to cover with cotton...if your wooden hull is up to the task.
     

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