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PostPosted: August 18th, 2006, 12:54 pm 
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Location: Durham, NC
I've been slowly adding strips to the cedarstrip playboat I'm building (our baby and toddler slowed things down considerably)...

I'm three strips into the curve of the chine now and MAN is it getting tough to bend those strips into shape. I'm getting concerned that in a few more strips, when I start to get close to the flat bottom that the strips will simply refuse to bend as much as they need to.

I don't have a recent picture - but you can see the boat a while ago here;
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Design is here;
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Anybody have any advice? I've thought about forcing my way through the strips but I don't know how feasible that will be. Plus, I don't know how that will affect the football area to be filled, the bend might just be too extreme.

Right now I'm thinking about ripping the strips so that they are no longer 3/4 x 1/4, maybe 1/2 x 1/4. Sure it would add more time, strips and more glue... but it would be easier to bend them. Maybe go back to normal strips after getting through the chine.

I haven't been doing a bead and cove up to this point, but I'm also starting to think about starting it soon to minimize potential gaps...


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PostPosted: August 18th, 2006, 3:12 pm 
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I always cut a fair number of 1/2 inch strips to deal with the problem you are encountering. Another thing you can do is put tie down straps around the boat at the difficult spots and slide the strips under to help force the bend. But the 1/2 inch strips will fix the problem.


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PostPosted: August 22nd, 2006, 4:56 pm 
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Have you tried using a heat gun to help encourage the strips to make the bend? The heat "melts" the stuff that holds the fibres together in the wood and allows them to slide past each other and the wood bends. As it cools, the fibres are again locked in position and the new bent shape. A little heat can do wonders, but of course the bends will probably still be tough.

Just thought I'd mention it in case you haven't already tried it.

Bryan

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PostPosted: August 22nd, 2006, 9:56 pm 
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When my dad made a canoe (I was 9 at the time), he steamed the cedar strips.

Maybe this would work for you:

He build a long plywood box to house the cedar and put a kettle of water at the low end on a burner. He boiled water and created steam for some time with the steam going up into the plywood box.

After the wood was good and hot and steamed and flexble, he would pull it out and quickly bend and staple it in place before it cooled.

No idea if this helps but it worked for him.


James.


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PostPosted: August 23rd, 2006, 8:51 am 
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I steam bent for the stems - while it wasn't that much work I can't see that fitting into the stripping schedule (get our toddler in bed, feed the baby, get her to sleep and then 30 minutes of "me" time before bed...assuming the kids don't wake up).

I'll start with 1/2 inch strips, if that doesn't work then I'll try the heat gun.

If it gets really bad, has anyone put in a strips to relieve the pressure of multidimensional bending? I'm thinking a strip that would start at the same point on the stems but that would follow a natural curve instead of seating on top of the existing strips. The gap between the strips (largest at the center) would then get filled in with multiple strips. Then the remainder of the canoe would get stripped like normal, but with a less pronounced curve in the football. I'll only do that as a last resort.


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PostPosted: August 24th, 2006, 5:48 pm 
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eranandrechek wrote:
If it gets really bad, has anyone put in a strips to relieve the pressure of multidimensional bending? I'm thinking a strip that would start at the same point on the stems but that would follow a natural curve instead of seating on top of the existing strips. The gap between the strips (largest at the center) would then get filled in with multiple strips. Then the remainder of the canoe would get stripped like normal, but with a less pronounced curve in the football. I'll only do that as a last resort.


If I understand what you are proposing here, it's pretty common practice for kayaks which are pretty curvaceous compared to the average canoe (I realise your canoe isn't average!). They're called cheater strips and they are great for reducing the amount of curve required. You can see a picture of the gaps here that I used in stripping my kayak to ease the curve.
The cheater strips were actually pretty easy to taper and fit into place. I discuss them a bit on my blog here and here. You can find a picture of the bow of the kayak with cheater strips after glassing here.

If I were you I wouldn't save the cheater strip option as a last resort, but incorporate it now, along with the use of the heat gun &/or the narrower strips (use every tool available!). On my kayak I wish I had used narrower strips in the tough spots.

The problem with steaming that I see is that you have just a few seconds to get it into place before the strip cools and the lignin in the cell walls regains it's rigid structure. That's what's nice about the heat gun - you just apply the heat as you go along fitting the strip in place. When heating the wood it seems to have little effect, then all of a sudden the lignin in the wood fibres release their hold on each other and the wood becomes pliable in that spot. Just be careful not to scorch the wood like I did (but on the other hand nobody will ever find that spot, especially since it was all sanded off).

I certainly understand what you mean about trying to squeeze in a bit of building. I started my kayak last October, shortly after our new baby arrived. I'm still not done as things were put on hold for the summer just prior to completion (we moved to a new house). Now that things are getting settled again, it's time to get started and finish this boat up. However my wife wants me to finish a hundred things in the house too (baseboards & trim, final touches on the hardwood installation, finish unpacking, more paint).

Good luck,
Bryan

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