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How To Repair Cracked Bottom?

Discussion in 'Wood and Canvas' started by OastlerLake, May 17, 2018.

  1. OastlerLake

    OastlerLake Curious about Wooden Canoes

    The bottom of my Chestnut Chum is badly cracked over an area of several square feet. With a thin spatula or blade, I could probably chip off the filler to expose canvas.

    No doubt many would advise a complete take-off and re-canvas. I have neither the experience, time, interest nor materials for the job, and I can't afford to pay to have the work done. The boat was restored professionally a few years back and except for the bottom area, is in great condition.

    It seems to me some kind of temp fix should work. I'm going to attempt to post pictures.

    Any advice will be greatly appreciated.

    OastlerLake 100_2700.jpg 100_2687.jpg
  2. OP

    OastlerLake Curious about Wooden Canoes

    Elaborating here - as I see it, this situation has gone beyond the point where shellac and multiple coats of paint are going to work. Possibly any flexible, reasonably resistant covering that will adhere to the canvas, might work once I chip off the cracked filler. However, because the repair area will be more than a couple of inches, whatever I apply will have to be sandable so that I can fair it once hardened.
  3. Greg Nolan

    Greg Nolan enthusiast

    No paint job is any better than its foundation – surface preparation is critical. Painting over peeling paint is pointless – the old paint will continue peeling, taking the good paint with it. But if the old paint is basically sound, and/or if you scrape/sand off the loose paint, a fresh coat of paint can make a canoe look better, even if the new paint job is not perfect, and even if the old paint is a bit cracked.

    Your photos, as I see them, show unusual cracking and peeling of the existing paint away from filler that appears to be sound -- do you know what kind of paint/primer was used. I suspect that paint was applied to a poor surface -- contaminated, poorly prepped, possibly water-based paint applied over filler that was not fully cured, or a very poor quality paint. Filler is usually integral with the canvas, having been rubbed right into the fabric’s weave when applied -- while it may crack, it does not usually crack and peel away as your pictures show; it is usually only paint that cracks and peels, as seems to be shown. Such peeling is caused by water getting between the paint and the filler and loosening the paint from the filler, which usually stays in place.

    If in fact the filler is cracking and peeling away from the canvas for whatever reason, that process may well continue on into other parts of the canoe over time. And if this is the case, recanvasing is probably called for.

    Have you actually tried to scrape away the damaged material?. You should do so over the entire affected area now to see just what your problem is -- if the problem is repairable, you will have to do this anyway. I’d like to see photos of the scraped areas to see what the canvas actually looks like -- the two bare spots showing in the photos above

    If it is just paint that is peeling, you have some work to do. New paint will not keep old paint from flaking (especially if flaking and peeling is the result of poor paint), so it is important to scrape and sand to remove all suspect paint -- and filler, if the filler is actually separating from the canvas -- the sign of a poor canvasing job. If the problem is poor paint (as opposed to just old paint that is cracking from age and drying out), you may have to sand it all off, and you might as well do the whole hull now. In any event, fair the edges of any chipped areas by sanding, or by using spot putty then sanding fair, depending on the depth of the chip.

    Sanding the flaking paint away may be sufficient, as long as what is under the old paint is compatible with the new paint to be applied, as it should be if ordinary oil- or water-based paint was used. Spot putty may fill in very minor scratches and dings. In any case a light sanding over all is called for to help new paint adhere. After sanding, at a minimum I would thoroughly wash the surface (soap and water, or TSP) and rinse completely, and let the canoe dry completely before applying new paint. Where the old surface may have been contaminated, as may be your case, it may also pay to use a primer (Zinsser or Kilz).

    If the paint is tight, even if crackled, a coat or two of paint will prevent leaks and give you a serviceable canoe. But discretion being the better part of valor, it is wise to have a small roll of duct tape along if some of the old paint/filler under your newly-applied paint decides to flake off. Even without a duct tape repair, the resulting leak will likely be very slow and will likely not interfere with a day of paddling.

    Here are some links to some discussions in these forums of painting over old cracked or chipped paint: see pp. 2-3 of this thread!&p=40689#post40689 starting at post 12, on bondo spot putty


    Repainting canoes is done all the time with all kinds of paints. Most use an oil based paint, and many use “marine” paints. Some use various other paints intended for exterior use – house paint, porch and deck paint, etc. Oil-based gloss paints are most commonly used. Water-based paints can work well, as can semi-gloss paints. They are easier to apply, and may be easier to touch up in the future – the chief disadvantage I have found with semi-gloss is that it is not so easy to keep clean, a particular problem with a light color. Using one of the premium marine paint over an old paint job is likely a waste of money. A good exterior paint – house paint, porch paint, Rustoleum enamel, or something similar – should do the job.

    I’m not sure what sort of “ flexible, reasonably resistant covering that will adhere to the canvas” there might be. If the problem is old peeling paint, applying new paint to a properly prepped surface should do the job. If the problem is failing filler, hiding the problem with another piece of canvas or other material will only add weight, be unattractive, and will not solve the problem -- your new covering will likely soon become detached from the flawed material it is covering.
  4. MGC

    MGC Paddlephile

    The canoe clearly needs a fresh canvas.....

    I am not advocating this approach but a friend of mine used this product on a failed canvas and swears by it. I never saw the finished result...but knowing that he always uses a dirty stick to stir our camp food should tell you a bit about how fussy he is.
    Once it's applied (over the failed canvas) you may repaint.
  5. Greg Nolan

    Greg Nolan enthusiast

    I would hesitate to use Gluvit -- an epoxy -- to coat a canvas that had any holes, rips, tears, even if small -- I would be concerned that it would glue the canvas to the wooden planking, making future restoration/canvas removal much more difficult.

    I agree that a new canvas is called for on this canoe -- but a couple/few years of use may be possible, as discussed in some of the links above.

    This canoe was professionally restored a few years ago; I would talk to the restorer to find out what he used and how he might deal with the current situation.
  6. OP

    OastlerLake Curious about Wooden Canoes

    Thanks Greg and MGC.

    To be perfectly honest about this situation, I'm not exactly sure what I'm looking at on the bottom of my canoe. I've never watched one being covered in the traditional way and thus don't know what the bottom would look like just as it's ready to paint. Would you see the canvas weave, or not?

    I thought I was looking at cracked filler, but maybe it's just cracked paint. I'll have to take another look and describe more fully (with photos) what's going on. Also will pop a few more cracked plates and examine their composition. If it's only paint that's cracking, it seems like that will be much easier to fix.

    Appreciate your responses.
  7. OP

    OastlerLake Curious about Wooden Canoes

    On the third link you showed (Carpediem's thread, "Minor restoratoin advice") , the bottom of my canoe looks very much like Carp's Canoe 030.jpg. What's peeling off there - paint or filler?
  8. MGC

    MGC Paddlephile

    When properly filled and sanded you will not see the weave in your canvas.
    If the weave is open (as it appears to be in at least one picture you posted) then the filler has failed. It is equally possible that it was not filled properly to begin with. The seeming buildup that you show in one picture is very unusual. The picture that seems to show a mass of cracks and puckering looks like it is too thick to be appears to be paint and filler...
    Frankly, attempts to save a failed canvas may allow you to temporarily use a canoe but ultimately you will need to get on with a proper repair in order to protect the hull from water damage.
    If you are located in an area with a local and active WCHA chapter you might reach out and see if there is anyone that would be willing to help you to get this sorted. Most folks that have canvased have made the tools that you need to stretch a canvas and would probably be happy to help.
    It is possible to remove a failed canvas and replace it in a weekend. Assuming that the hull is structurally sound you can remove the rails, bang plates and old canvas in a couple hours. A new canvas will go on in three or so hours (or faster) and filling it will be done in two or three hours. The slow part of the process is that you then need to allow the filler to cure for 6 plus weeks (I wait 10 or more) before sanding and prepping for paint.
    Good luck......
    As Greg notes, you should be talking to the person that restored this....if it's a recent restoration they should be looking at it.
  9. Andre Cloutier

    Andre Cloutier Firestarter. Wicked Firestarter.

    What MGC said. The canvas, filler and paint work together and as the paint is no longer adhering, the filler has failed. You can try to sand and paint but a new canvas is fast and easy. Strip it yourself and seek help to canvas it, then fill and paint. total materials should set you back no more than $300, likely less. It will not only make your canoe useable but maintain its value as well.
  10. OP

    OastlerLake Curious about Wooden Canoes

    Thanks all for the advice. I'm doing a fix so I can use the canoe this summer.

    What I did learn is that the re canvassing on my Chestnut was done about 10-12 years ago and the filler was a lead/oil base.

    Even if I had the materials, equipment and know-how to re-canvas in the same mode, I would not do it that way. From what I've seen here and on the canoes of collectors. the filler is eventually going to crack.

    I see it as being similar to old-time window glazing: it worked well but eventually cracks regardless of how well the job is done. Now that I'm cleaning up and sanding the bottom of my canoe, I see that the filler is basically a putty-like material that's become brittle. The sides of the canoe look fine. The problem areas are on the bottom, near amidships, where I kneel and where the bottom flexes most.

    There has to be something better. I've watched Orca's latex mastic job on Youtube and will investigate that method if and when I re-canvas.

    Thanks again, good summer paddling to all.

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