"Oil-caning" after staples removed......

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Sherm
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Location: Milledgeville, Georgia

"Oil-caning" after staples removed......

Post by Sherm »

After removing staples from my hull the bottom of the canoe "oil-caned" up and gave
the bottom a more rounded shape.
Is this a common problem? During fiberglassing I think I can put tiny "screw-eyes" underneath and pull the hull back down to the forms with "tie-wire". It has a
nice round shape you see with "white-water" canoes, (which may be a benefit for me).
but the original design is "altered". It may not be a big deal since it raised up no more than a 1/2 inch or less. (Hiawatha)
Rick
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Location: Bancroft, Ontario

Post by Rick »

It might be possible to weigh down the hull with sand bags, taking care not to add too much weight, and then get underneath to somehow glue the hull onto the stations so that the right shape is preserved. After the hull is glassed, the glue would have to be cut away carefully, maybe with a Dremel-type disc.

Maybe others could describe this better... there have been threads with hot glue being used to fasten the hull onto stations.

(BTW, oilcanning happens when hull bottom flexes up and down with shifting weight when it is in the water because it is not rigid enough... the hull springing away from the stations is something different.)
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Sherm
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Post by Sherm »

Thanks Rick, I may try the hot glue, or some kind of combination....
Your right about the "Oil-Canning", that was the first thing I could think of to
describe it. I must've had the "football" area under alot of tension.
:thinking
Tom in MN
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Location: Eagan, MN

Post by Tom in MN »

I suspect that if the strips pulled away from the forms that the forms were not cut to the correct specs. I have never had this happen to me before. The key is that the hull makes a straight fair curve and if it is out of line, and leaves a depression or a hump, you have to pull it back fair before fiberglassing. Your method with small scews into the forms and a piece of wire or fishing line should would to pull it back into place, then cut the line after you fiberglass the exterior. After you get it where you want it, lay a strip down the hull and check to make sure there is no gap where you might have pulled it too far back. Should be a pretty easy problem to fix.
sedges
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Location: georgia

forced in final strips

Post by sedges »

The problem may be from the pressure of forced - in final strips. If you have strips bulging out from the mold the cross sectional amount of striped hull is longer than the distance over the mold. The staples held it in until you pulled them and the screw eye and line will hold them in when you glass, but I fear the stress will cause it to bulge out again.

I think you need to address this before you glass. You may need to take a thin saw blade and make a cut along the keel line. The kerf might be enough to relieve the pressure. Than push some glue into the kerf and fasten it down to harden. I would suggest a piece of a band saw blade, or even a course tooth hack saw to make the cut. I doubt it needs to be as thick as a circular saw blade.

Your strips ought to rest on the mold. However you fix it, do it before you glass.
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Glen Smith
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Post by Glen Smith »

What Sedges said.
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Sherm
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Post by Sherm »

Thanks Ya'll, I pulled down the hull using dowels glued to the hull and the strongback.
I'm thinking that prying in the football area to get a tight fit maybe "overkill".
I still may cut a thin kerf to relieve the pressure before glassing.

I had this same problem with my first canoe but contributed it to my first time and
inexperience.

Image

Image
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Sherm
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Location: Milledgeville, Georgia

Post by Sherm »

I ended up removing a 1/4 inch of wood down the middle of the football to
get the bottom to rest on the forms. I used a jig saw and had to make several
passes, each while pushing down with each cutting. I'm still a little puzzled how it
had gotten this far "off".

Thanks for everyone's response and advice.........
AlanWS
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Location: Shorewood, WI

Post by AlanWS »

When did you put the strips on? Is it more humid now? That could be the difference.
Alan
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Sherm
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Post by Sherm »

No more than 1 week, humidity is the same...or close to the same...
mbolton
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Location: Michigan

Humidity

Post by mbolton »

I recently experienced the same problem on a little WW boat I'm building. I pulled all the staples and it was sitting under my carport for a week or so when the temps changed and it got more humid. It made the strips swell and raised up 1/2" or so. Pulling it back down somehow from the inside should work.
mbolton
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Joined: Sat Jan 14, 2006 8:52 pm
Location: Michigan

Post by mbolton »

Oops, you got it already :embarassed
It'll be interesting to see if they shrink back some?
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Sherm
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Post by Sherm »

Thanks, M Bolton, I think everythings going to be OK, I'm trying not to worry
to much and move forward. Experience is a great teacher.
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