gunwale bending question

[jchu]

I am confused about this. Did a search,here, not much info. I know that most canoe builders have a jig to bend up for the rise at the end. I think I've seen someone cut with a band saw the rabbit for the shape of the hull. The problem I have is that my gunwales are maple. I have some 16' maple but the width is by 8". Not wide enough for a rabbit cut. It looks like the original was a straight piece and steam bent the whole way as the grain follows the same on the hull.
Is it possible to steam bend it on a full size jig and is that a something done often?
What should be my best approach?

 

[Andy Hutyera]

I believe that steam bending your gunwales to the profile of the canoe will work fine for you. Just rip your maple to the appropriate size and use a dado head to put a rabbet on the inside of the outwale to leave room for the canvas and filler. You will need to make a bending form as you describe. Steaming can be done one end at a time just using a piece of stout PVC pipe and a steam source. Even if you don't get the curve just right, it will preform the wale enough to allow you to clamp and screw it in place. The advantage of steam bending as opposed to sawing is the retention of stregth by not severing the longitudinal wood fibers (assuming your wood is straight grained). If you don't want to make a bending form you might try the method described in a recent post entitled "gunwale replacement" in the wood canvas forum, but I tend to believe the wood would cool off too much for that method to work very well.

Hope this helps!

 

[jchu]

Thanks Andy, I thought that might be what they did. Its a cedar rib canoe so no canvas. I did think about one half at a time. I will go look for the post you mentioned. I do like the idea of better strenght by not cutting the grain.

 

[Darryl]

Jeff,
The jig that was used originally to bend the gunnels for your canoe was only about 3 feet long, it really only bends the last 16-20 inches. Its easier to taper the gunnels first (starting 25-30 inches from the end) and then steam and bend them.
Cut the gunnels as straight pieces and let them follow the shape of the hull naturally amidships. There is no need to steam the whole length, even though these gunnels are wider then most. The length of the stock allows for the dry bend that you need.
Good luck

Darryl

 

[jchu]

That makes sense to Darryl Thanks. Long way away from it but looking ahead. Have the stock ready. Will decide best course of action at that point. But really had no idea how it was done except for end jig. I would hate to loose the shape of the canoe.

 

[Darryl]

Jeff,
If you are concerned about the shape collapsing while installing the gunnels you can install some temporary thwart-type-things to prevent any movement... but I doubt that it will be necessary.

Darryl

 

[Mark Reuten]

Just throwing in my two cents on beding in place.
Some scraps of 1x2 clamped across the inwales work well for an in-place jig.
A section of grp wind surfer mast makes the best steam tube I've ever found. The thinner wall thickness allows it to be slid up you gunnel closer to you first clamp. They also do not deform with the heat the way a pvc or abs tube will. I've had pvc tubes turn into a piece of over-cooked canalloni. Carbon fibre masts work even better.
Maple is a bit tougher to bend so giving the gunels a coat of linseed oil first will help them hold the heat a little longer and help to avoid water stains. They come out of the steam a little slimey so have a rag on hand.

 

[jchu]

Thanks Mark, it will be a few months but have picked up the stock. I just took a windsurfer mast to the dump last summer I do think it would have made a good steamer. I never knew I would be doing this at that time.
Checked out your website. Very nice. Looks like you have enough to keep you busy. Must be a passion that keeps you going.

 

[Mark Reuten]

Passion is one way to put it. You have to have it to do this stuff for a living. A steady flow of work comming in is another. I can never seem to get done. The list is always a year long it seems.