Bending Ribs

fred capenos

Canoe Pilot
I bent 7 ribs for the first time today and would like to know how long do I wait before I unclamped them from the canoe. Thanks in advance.




Fred
 
bending stems

Please disregard the last question. I found the answer in Stelmok and Thurlow's book...which is overnight.
 
Fred,

This issue doesn't come up for those of us who are builders as far as ribs go since they stay on the form until the planking is done. For what it's worth, I can tell you that when I bend stems, I tend to leave them on the bending form for about a week. I usually check the moisture content with a meter and remove them when they're back to what the stock I cut them from is. I've honestly never done any experiments in this area but I've always had a suspicion that once the wood has cooled and dried out that you don't gain much by waiting longer. Cedar ribs being much thinner than stems and more porous, I would guess a few days would be sufficient. Hopefully someone else will jump in with a little more usefull information!

SORRY I DIDN'T SEE YOUR SECOND POST!

ANDY
 
Another thought... When I bend replacement ribs ( on the outside of the canoe), I let them set for only 5 or 10 minutes. After that I remove them from the outside of the canoe and immediately place (force) them inside the canoe where they will go permanently. This allows me to make any minor adjustments to the rib's position. Sometimes the rib needs a little twist or whatever to keep it square to the existing planking. I try to leave as much planking as possible in place to help support and keep the correct bend in the rib. Then I clamp them in place for a few days before fastening. Of course, I only do a couple ribs at a time, but this works for me.
 
i guess i'm a little impatient but on the last 2 canoes i bent replacement ribs for i installed the ribs directly inside the canoe. we pushed the ribs down into their proper location, waited a couple of minutes, trimmed the ends about an inch long then turned them a little to slid up under the inwale. adjusted them and clamped into place until the ring nails were hammered home. then just finished tacking. you need to sight along the hull to check that you haven't pushed them in too hard and deformed the hull.
 
Bob,

when I did that, the ribs shrunk and created gaps between the rib and planking.

The process I follow now is to bend the ribs over the outside, after carefully measuring the inside and outside dimensions, and marking on the outside where each rib is to be bent. We (I recruit either my wife or son to help) bend the ribs and clamp them in place, and let them set overnight.

The next day they are installed, usually tacking in place starting from the center of the canoe, the ring nails are the last to be installed.

Sense I went to this process, I haven't had to remove a bad rib (yet). :)
Prior to using this process, I often had to replace poorly fitted ribs.

When replacing a lot of ribs in one section, I only remove a few at a time and then only every other rib.

Dan
 
good point, hadn't thought of shrinkage. anyway both the canoes i did that on are fine so far. 2 years on one 1 year on the other. i may have dodged a bullet though. i'll do it different next time. thanks.
 
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