Lapping canvas at stems

[snamelc]

We've built 5 wood and canvas canoes to the 1915 Old Town Ideal form and always had trouble with wrinkling of the canvas at the stems when lapping and sealing. We finally came up with the idea of stretching an old bicycle inner tube over this joint to help smooth out the canvas and it has worked quite well for us. It slows down the drying process but has made a tremendous difference in smoothness of the joint. Also, one instruction we were given early on was to use bedding compound in this joint to seal it. Unfortunately, the bedding compound never really "cures" to strengthen the joint and it tends to let go over time. Just using the doping compound used to seal the canvas has worked far better, and I'm sure that's what most of you are doing. Any other "tricks of the trade" out there for getting a good joint?

Bill

 

[Rollin Thurlow]

The wrinkles in the canvas are caused by having the stem tacks too far apart. On the final layer of canvas the tacks should be spaced three or four per inch. With this many tacks its important to have the smallest fastening possible or all the fastenings will split the face of the stem. I use 5/16" copper tacks and even 1/4" copper tacks on the new hulls that have a clean face.
The bedding compound comes in handly to hold down a winkle as its being tacked but it shouldn't be needed for any sealing or certaily not for any strength.
Even with the many stem tacks the surface of the lap will be kind of rough. after the filler is dry its easy to sand a smooth surface on the face of the stem. The stem band is covering up the face so its no problem if you sand into the top canvas lap or even expose the top surface of the tacks.

 

[Blue Viking]

I was wondering what weight canvas was used while restoring or building those canoes. While I admit that I am still a novice at this, I have re-canvased a 65 OTCA, and 18' OT Laker, and a WC Sebago lake boat. Have used both the 8 and 10 oz canvas and that includes two transoms, I have been very satisfied with the results. One little thing I found that helps is to bed it good and really get the standard filler mixed into the canvas for shaping a little after...My personal feeling is that by working the canvas and stretching it in the right direction when tacking results in a tight smooth fit, AND as Rollin said...tacks,tacks, tacks until your hitting your own fingers instead of them...AGAIN!....just throwing in my 2 1/2 cents worth...WE shall see what happens with the Chestnut that is about ready to canvas and fill still building the 13' form that is the replica of the Stowe canoe out of Vermont....wide,short, light, and stable for the solo flyfisherman!

 

[Fritz Koenig]

Canvas shrunk - Restretch?

Okay so I followed the book and everything worked great except that I didn't finish all of it in one day. When I got home from work today and went to tack the last end I found that the canvas was too small and nolonger fit over the end. It appears that the canvas shrunk. It seems like I need to try to restretch the untacked end. Any thouhgts on this. Would wetting it help or hurt?

 

[Dave Wermuth]

my guess

If it did fit before then I'd pull out some tacks (staples) and then try re-stretching it. I have use a little water to take out wrinkles before. Not sure that it would let you stretch it more if it were wet. Nothing to lose. Much to gain. Try it dry first.

 

[Fritz Koenig]

Right, so the question is how do you get hold of the hull to do the stretching? One thouhgt is to screw a piece of plywood to the seat and thwart holes and then attach the cable to the plywood. This would distribute the stress over six spots on the inner rails and not impede the canvas. Another thought was to hang the canoe from the wooden canvas clamps and add a little weight to it and let the weight stretch the canvas. Canoe is a 1958 13' CS grade 50 lb model.

 

[Dave Wermuth]

try this

Rather, try a fabric stretcher first. Just get ahold of it and work it back where it should go. You'll have to take out a bunch of staples but it should work. gil canvasses canoes at the Quiet Water Symposium every year and uses nothing to stretch except his own muscles. AND, they are perfect!
A 13 foot OT is a little more challenging than say a 17 footer when it comes to getting the canvas to pull out smooth, but it does. idon't remember where I got my fabric stretcher from.

 

[Fritz Koenig]

Too short

Thanks Dave. When you say fabric stretcher do you mean the canvas pliers? I can't pull it enough. Unfortunately I come up about 1.5 inches short of the stem. Limp it is about 3" short. Imagine my surprise. I know I had enough when I cut it as I cut behind the clothes pin. It was all going so well.

 

[Fritz Koenig]

Too Tight

Thanks Gil, when you say hand pull do you mean that he did not stretch the envelope as in Stelmock and Thurlow suggest?

 

[Fritz Koenig]

Result

Thought I would post the result.

I used the plywood as noted above I cut the canvas and attached the wood clamps to the ends of both pieces and used the come-a-long. I stretched it a couple of inched past the end of the canoe (about where I thought it was before I cut it down from the initial stretch) I left it for several hours stretched. Once I removed the clamps etc. I was able to hand pull the canvas around the end and finish the job. I don't think it will pull away but time will tell.

Althoguh I may have overstretched it to begin with I think the hight humidity the day of the initial stretch and leaving it overnight contributed to the problem.

 

[jphelps1511]

How to finish re-canvassing ends?

I was looking for information on recanvassing an Old Town canoe and came across the discussion board on WCHA.ORG. This is my first attempt and I've run into some trouble at the canoe ends.

I'm using the winch and sling technique with weights in the canoe to hold it down and stretch the canvas out. When I got to about 7 ribs from each end, I couldn't pull the canvas tight enough to remove a bump of extra canvas right at the bottom center of the canoe. Thinking that I could pull this by hand, I removed the winch and holding boards from the ends. Well, I cannot pull the canvas tight enough and I think that I have to set up the sling again and repull it.

My question is, after setting up the sling again, should I expect that there will be an increasing amount of "bubble" or excess gap along the bottom of the canoe (this may be called the stem, but I'm not sure)? With the curve of the canoe at the ends, I'm thinking that this may be normal and that's it's important to attach the canvas to the gunwales for all of the ribs to keep the proper tension, remove the sling, cut the canvas down the middle and then pull and tack the overlap down the middle of the canoe. Would this be correct?

 

[Fritz Koenig]

Just my opinion

I do not have a lot of experience as I have just doen one. But what you are suggesting sounds like you are on the right track. You should not have to cut the canvas back past the stem and I would think that you should be able to hand pull the wrinkle out rather than put it back on the stretcher.

Hope this helps.