Preparing canvas

Daniel Day

Enthusiastic about Wooden Canoes
Hello All,
I have gone through past posts, and read some books but could not, or missed, anything about preparing the canvas. Old Town sells regular and pre shrunk. I can get #10 canvas locally, but not pre shrunk.
1. Should I wash it first to get the sizing, manufacturing chemicals out of it?
2. Should I stretch it only when it is dry? Obviously it will stretch more when wet.
3. Does it make sense to get the pre shrunk then stretch it?
I am at the point of setting up the rigging to stretch the canvas.
Thanks for the input.
Daniel Day
Spokane, Wa.
Dan - I've canvassed only one canoe and used dry, mildicide treated canvas. This is the first I've heard of "pre-shrunk" canvas for canoes.
I don't know of anyone applying wet canvas.
Thanks ebeeby,
Not quite what I was looking for. Old Town sells a "pre shrunk" canvas. Therefore my question. I am still looking for an answer to, if anyone prewashes the canvas to get the chemicals out of it. Then dry it.
This will be the one and only time I am going to do this and I want it to be right. I would find a way to pay someone else but there is no one around Spokane or North Idaho (I live 300 mi from Seattle) that recanvases canoes.
Again Thanks
Daniel Day
Spokane, Wa.
Dont know why the "pro's" havent responded to your questions. I have only re-canvassed one canoe and one wood and canvas boat. Before I started, I went to visit Bill Clement in Billerica in Mass. and did some brain picking. I bought my canvas and other supplies from him. I was instructed on how to do the "upside Down" method becasue I was going to be doing it outside. I was informed that this canvas was pre-shrunk and contained a material to stop bacteria(?) from eventually attacking the canvas and causing the rotting..Therefore I kinda think pre-washing would remove it so when I do my next 2, I definitely wont pre-wash..The stretching went really easy and I found that with the right tension, the tacking went rather smooth. I also found that the cutting and tacking of the stems after releasing the canvas clamps works rather easy if you take the time to figure the strretching and tacking as you go along..In fact it falls in to place for want of a better description.(and the good think is if you get alittle wrinkle you pull the tack(s) and re-stretch...I would only suggest that you inquire if that source for your canvas has it saturated with some kind of Mildicide to prevent it being attacked by the "things" that cause rot...Even saw one site on here where the person saturated his canvas with "Cepacol" mouth wash to make sure the "bugs" wouldnt attack the canvas... Well.........thats my 2 cents worth...may not help you but I dont think I would wash any canvas or put any on wet!...have had my boat and OTCA out and they dont leak and have had rain water in them and they are now put away for the winter and are in fine shape...Good Luck..
PS: see if you can find one of the restorers email site and send them a personal email about your conerns.;)
My $.02

Cotton canvas duck cloth comes in various grades and weights. A #10 from one mill may not be the same weight as another and can range in 2-3 ounces between the two. Why, the grade represents the weave tighness which will relate to shrinkage. The tighter the better for filling and waterproofing the canoe. The best tight weave canvas I believe is grade "A" might want to check with an art supply or awning store for clarification. Canvas with a tight weave will not need to be pre shrunk or shrunk at all. The sizing in the material will not hurt anything. My hunch is that a loose weave would have to be shrunk to make it tight. Another hunch is that a loose weave is an import or lower quality than the grade A. What if it shrinks so much that it will not cover the canoe? Buy from one of the builders on line and then you can be assured that you are using the same as them. I have never heard of any of them washing their canvas before installation on the boat. If you find canvas that has bumps and streaks running through it, be careful, it may not be the quality that you want and may shrink considerably. I'm not the expert, just picked up a little (very little) knowledge along the way. A friend who works at Astrup Awning also helps.

Best of luck,

Ric Altfather
Dan I live about 350 miles to the east of you over here in Montana. If you plan to do this only one time why don't you just buy some canvas from one of the builders in the directory. I've canvased 7 canoes and it really isn't a difficult job once you get everything set up for it. I'd buy canvas treated for mildew rather than pick up some local #10 which is readily available over here as well. Better off using something that's been proven to work for canoes.
The preshrinking of the canvas is not a necessity. I belive shinking the canvas became popular amoung many amature builders. One of the commen things that new builders do, is not pull the canvas tight enough. By wetting the canvas after it was on the boat, the canvas would shink, assuming it was already about 90% tight, and everything would be fine.
Most professional builders knew how to pull the canvas to get it tight so they could skip the wetting and drying out time period and go stright to the filling. Once the filler is dry the canvas is more or less locked in place and very little shinking would occure latter when the boat was geting wet, IF it was a good grade of canvas that you knew was not going to over shink. Lesser grades of canvas could keep on shinking so much after the boat was in use the canvas could pull away from the rails. Some builders knew how to stretch the canvas properly but did not want to take a chance that the canvas would latter overshink so they would go ahead and wet the canvas down and let it shink and dry before they ever put it on the boat.
One of the side benifits of having the mildew treated canvas is that it is preshuunk so the builder does not have to worry about the possibility of the canvas pulling away from the rails. Of course you lose the ability to shink the bare canvas if it is not tight enough on the hull.
Hello All,
Thanks for the input.
1. Get a top quality canvas from a known vendor. Not pre shrunk.
2. Hull and canvas treated with a mildewcide.
3. Get a proper stretch on dry canvas. It seams that this is a must. If not this may be what leads to cracking later on?
4. There are lots of filler formulas but I will go with Old Towns formula and not expirment.
5. Temperature and humidity seam to be a factor when canvasing a canoe until the filler and paint dry.
The bad part is the weather has turned cold and damp. Dry canvas will soak up the moisture. I could set up my basement to control temp and humidity. I am sure my wife will have input on that.
Thanks Again
Daniel Day
Spokane, Wa.
...and remember that mildew prevention is done by treating the fabric with poison (usually arsenic compounds) so wash your hands frequently when working with treated canvas. It's not as benign as it looks.