Canvas relaxed suddenly for no apparent reason?
- Thread starter John Visser
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John Visser
Curious about Wooden Canoes
Accidentally hit post too soon...... within an hour of having the canoe flipped over, the entire canvas had relaxed and was full of wrinkles and bubbles. It had shown no sign of looseness throughout the stretching process, the filling process, the priming or sanding or varnishing process. Just out of nowhere all at once it is loose.
This was canvassed with #12 untreated duck canvas, treated with wood life coppercoat as mildewcide, filled with Kirby's filler and primed with Kirby's marine primer. No major changes in temp or humidity, it has been in my shop for years. Had months for the filler to cure. I'm going to recanvas it, but would like to hear any ideas on how this could happen? What went wrong? I've canvassed probably 60 canoes and have never had this happen before.
This was canvassed with #12 untreated duck canvas, treated with wood life coppercoat as mildewcide, filled with Kirby's filler and primed with Kirby's marine primer. No major changes in temp or humidity, it has been in my shop for years. Had months for the filler to cure. I'm going to recanvas it, but would like to hear any ideas on how this could happen? What went wrong? I've canvassed probably 60 canoes and have never had this happen before.
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John Visser
Curious about Wooden Canoes
This is the shortest canoe I've ever canvassed and it was a little tricky to get it right so I realize it is probably a stretching/tension error. But why would it wait this long to show up, and so suddenly go from apparently fine and tight to loose in a matter of less than an hour with no other major changes happening?
1905Gerrish
Loves Old Maine canoes
John,
You say no major changes in temp or humidity, but I am going to say it's the humidity. I see you are in NY and there is poor weather in some parts. See what happens when the weather clears after the holiday. I wouldn't throw the towel in and recanvas without trying to pull it a bit tighter if the canvas doesn't tighten again. Those short football canoes can be difficult to canvas. I can remember the ends being a pain on the shorter few I have done but if it was tight before? Give it a week!
You say no major changes in temp or humidity, but I am going to say it's the humidity. I see you are in NY and there is poor weather in some parts. See what happens when the weather clears after the holiday. I wouldn't throw the towel in and recanvas without trying to pull it a bit tighter if the canvas doesn't tighten again. Those short football canoes can be difficult to canvas. I can remember the ends being a pain on the shorter few I have done but if it was tight before? Give it a week!
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John Visser
Curious about Wooden Canoes
That is a good point. We've had drought conditions for a couple weeks then suddenly rain for almost a week straight. My shop is decently insulated but not entirely isolated from outdoor conditions. I'm going to leave the canoe alone for a bit. I have a 15 footer I'm hoping to canvas sometime in December so will probably try to schedule redoing this 11 footer in that time as well if needed. But I'll leave it alone and watch how it reacts for now.
Dave Wermuth
Who hid my paddle?
I can't imagine that installing thwarts and seats could have been a variable? But if it was even a small amount of change from the temporary thwarts, then you might have the answer? A canoe that short is possibly a factor. Humidity is generally blamed, as is moisture of any sort. (I'm thinking of canoe paint bubbles that resolve as the canoe dries after a trip.)
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John Visser
Curious about Wooden Canoes
Well I pulled off the compromised canvas today and it was ridiculously brittle. Ripped like it was thick paper. Not sure how that happened. Maybe from the mildew treatment I applied? I usually use the pre treated canvas from Northwoods, but they don't have it in #12 anymore. Maybe the brittleness was a factor in why it didn't remain tight?
Worth Gretter
LOVES Wooden Canoes
Have you considered Dacron?
A search on this site will provide lots of info. A couple of the most recent posts are from Howie (your neighbor in Western NY!) and myself.
A search on this site will provide lots of info. A couple of the most recent posts are from Howie (your neighbor in Western NY!) and myself.
Dave Osborn
LIFE MEMBER
I’ve used Jerry’s Artarama 6 yard canvas blankets and 30 yard rolls for many years. Prices are great, delivery is quick, quality is great. Never an issue.
I used to buy 50 yard rolls elsewhere, but shipping was costly and the weight was unmanageable for one person.
chris pearson
Michigan Canoe Nut
Rollin suggests spraying the green,below grade water seal, right before using his filler. Correct me if I’m mistaken…….
patrick corry
solo canoeist
Would you please elaborate on this? To what product do you refer? Thank you.
David Satter
Wooden Canoe Maniac
Maybe he means Cuprinol, the green one for below ground contact. We can't get that one in NJ anymore. I used to use it a long time ago. I never wet or spray the canvas. I just add a mildewcide to the filler and mix well. Maybe humidity. I remember canvasing a few 10 or 11 foot canoes they were a pain to canvas.
patrick corry
solo canoeist
Thank you.
This seems like a valid option.
One trick for canvasing the little bathtubs is to stretch the canvas on the bias. That is, rather than fold the canvas in half when stretching, skew the ends so the the canvas gets stretched more on the diagonal relative to the weave.
Howie
Wooden Canoes are in the Blood
I had something like this happen to me once on a 13 foot canoe. I figured it was caused by the canvassing technique I was using at the time.
As I recall I canvassed & mudded this 13 footer in the late fall, and first noticed the wrinkles a few weeks later as the temperature fluctuated down. The wrinkles seemed to come & go. I figured it was triggered by the temperature change. Now, back then I would stretch the hell out of the canvas, then after a few hours I would start at the center of the canoe and use the canvas stretchers along the rails, pulling & stapling my way to the stem area. I then would remove the canvas tension and attempt to staple along the stems. Of course the canvas would relax a great deal when I removed the tension, especially by the stems. So I would have to pull the canvas tight again as best I could at the stems, stapling as I go. But at the end I would inevitably have new wrinkles at the rails, so I had to remove the staples, pull up on the canvas again and re-staple.
This technique had worked ok for me before for longer canoes, but I figured it was inadequate for the 13 footer, and I fugured it was due to the canoe's stubby shape by the decks. My guess is that when I was done canvassing the canvas fibers were no longer as 'straight' as they were when the canvas was stretched due to all the re-work I had to do to remove the wrinkles that appeared along the rails after I was done with the stems.
So I changed my canvassing technique. I still stretch the canvas like hell for a few hours (when I use canvas). But before I start stapling I remove some of the tension to let the canvas relax a little. Then I use the canvas pullers along the rails to stretch 'up' along the rails as normal (I figure this is made easier & more effective by the relaxed tension). But then I add some staples along the outside of the stems at about 3" or 4" intervals (these will be removed later). Then I remove the tension completely. Then starting at the top of the canoe I staple & trim the canvas by the stems as normal, but the process is now much easier because the staples I added to the outside of the stems are keeping the canvas in the same position (more or less) as it was when stretched. These these side staples are removed as I work my way down to the bottom of the canoe.
Never had wrinkles appear again. Not sayin' this was your problem though...
As I recall I canvassed & mudded this 13 footer in the late fall, and first noticed the wrinkles a few weeks later as the temperature fluctuated down. The wrinkles seemed to come & go. I figured it was triggered by the temperature change. Now, back then I would stretch the hell out of the canvas, then after a few hours I would start at the center of the canoe and use the canvas stretchers along the rails, pulling & stapling my way to the stem area. I then would remove the canvas tension and attempt to staple along the stems. Of course the canvas would relax a great deal when I removed the tension, especially by the stems. So I would have to pull the canvas tight again as best I could at the stems, stapling as I go. But at the end I would inevitably have new wrinkles at the rails, so I had to remove the staples, pull up on the canvas again and re-staple.
This technique had worked ok for me before for longer canoes, but I figured it was inadequate for the 13 footer, and I fugured it was due to the canoe's stubby shape by the decks. My guess is that when I was done canvassing the canvas fibers were no longer as 'straight' as they were when the canvas was stretched due to all the re-work I had to do to remove the wrinkles that appeared along the rails after I was done with the stems.
So I changed my canvassing technique. I still stretch the canvas like hell for a few hours (when I use canvas). But before I start stapling I remove some of the tension to let the canvas relax a little. Then I use the canvas pullers along the rails to stretch 'up' along the rails as normal (I figure this is made easier & more effective by the relaxed tension). But then I add some staples along the outside of the stems at about 3" or 4" intervals (these will be removed later). Then I remove the tension completely. Then starting at the top of the canoe I staple & trim the canvas by the stems as normal, but the process is now much easier because the staples I added to the outside of the stems are keeping the canvas in the same position (more or less) as it was when stretched. These these side staples are removed as I work my way down to the bottom of the canoe.
Never had wrinkles appear again. Not sayin' this was your problem though...
