Humidity and the Stripper

[Peach Canoe]

There's a strong case to be made for maintaining humidity levels when glassing the stripper canoe. This especially relates to the time interval between glassing the outside and the inside.

Here's an article by Tom Pawlak of Gougeon Brothers that is very interesting. Tom has been a great resource for me over the years, and I communicate with him often.

http://epoxyworks.com/index.php/panel-warping/

While I've never done this, I can see where keeping a shop humidity logbook would be a good idea when building the stripper.

 

[MacCamper]

Huh, interesting read. And short enough for me to stay focused. Thanks

 

[Peach Canoe]

I've noticed that a stripper may change shape after a while-- I've seen a couple of shallow ellipse hulls morph towards 'round'. There's one case I know where a shallow arch became somewhat of a shallow V, with a clearly-defined keel where no keel exists on the forms.

Perhaps the stripper technology naturally creates a canoe-shaped spring.

We can all recall compound-bending strips around tight corners and clamping/stapling them in place while the glue sets up. There's a lot of potential energy stored in a stripper hull, and it's not surprising that some boards constantly strive to be somewhere else.

While it's labor-intensive, I think it's worth considering heat-bending individual strips in those 'oh jeez' bends, so they lay down happily, stress-free.

 

[Jim Dodd]

I try and glass the inside of mine as soon as possible. My son's on the other hand, has been setting with out glassing the inside for about two months, and yes it is changing slightly.
A friend took 10 years to glass a stripper, and thought it changed shape some, it was still paddle worthy.

I've not tried heat bending.

Jim

 

[Mihun09]

FWIW, when we soak and steam white cedar ribs on a w/c restoration, even leaving the rib clamped on the jig for two days, when removed the rib relaxes somewhat, say 25% but since it is cedar it complies when put into place in the boat. Eventually the wood loses that stress as ribs removed after 50 odd years hold their shape.

Karin

 

[sailsman63]

I've actually witnessed the phenomenon, though I think the author is overstating the need to catch it early.

On my first strip build, I was working in a barn (free-flowing air) I'd removed the canoe from the forms, and had cleaned up the inside of the hull. We had a series of rather hot, dry days, and the straight-sided hull, with a 36" designed beam, folded in on itself until there were only 12" between the shear lines. I'd never seen this before, so I just about had a heart attack. I was making plans involving damp towels, and a hairdryer to try to adjust the moisture content in the cedar. A day later, the whether broke, and we had a nice t-storm. The canoe relaxed right about to where it should be with no further interference from me.