Kayak building Wood strips - problems to watch out for


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1b. Wood strips - problems to watch out for

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This is what a normal bead and cove wood strip should look like. It is important to mill it a fraction over 1/4" which is about the thickness of the lines on carpenters measuring tape. A reading on a caliper would make it 0.275inch (6.9 mm).
Thin cove edges just crumble into the glue line as you run the glue bottle and you have to fish out the splinters for the strips to get good contact.

Strips can be made in any width (1/2" - 1") but I highly recommend to mill 5/8" strips mostly and 3/4" if the wood is very pliable. They may not cover the surface as fast as the 7/8" but they bend far better and conform very well to convex and concave compound surfaces. The harder the wood the more important this becomes.
This factor alone will make stripping faster and kayak models with harder chines, pinched keels or small radius curvatures (like the deck bow and stern) can be built that much easier.
Once you are set up, you can mill two or three different strip width to cover flatter areas faster and tighter radii easier. If you order strips, you can get different widths as well.

How to calculate the footage of strips for your project.

Strip milling problems
This is by far the WORST problem to encounter when building. You may mill 1000 feet of strips and because of a moment of inattention during ripping the plank moves away from the fence and a few feet of thin strip slip by your guard. You than proceed to put it in the kayak and don't notice it until it's too late.

A shallow spot like this must be sanded fair but this just creates an unfair hollow in the surrounding area. One unpleasant option is to sand the whole wood strip core thinner, which I would not recommend for structural reasons.
What else can be done?

cut the few feet of the strip out along the joint as if you were inlaying a decorative strip, then glue in a new strip.

if the strip is sunken really deep, you can shape and glue another strip on top of that and plane/ sand it flat later.

Build up the low spot with clear epoxy when fiberglassing. This may add a bit of weight but the surface will be fair and smooth.

Try to watch out for this as much as you can. If your strips are milled well it is less likely to happen.

This problem arises from poorly adjusted router fence, low finger board pressure on the strip or a strip that is pushed through the router too fast.

A large void in the glue joint is the result. This may not be too serious if the void is filled with glue but it often isn't which makes the wood core weaker. Too much glue just adds pounds to the kayak.

With time, this problem may cause ridges printing along the joints through the fiberglass skin. See 'print through' problems.

A similar problem as above but you will notice it very easily. The beading bit did not form the cove deep enough. This can happen very easily with hardwood. Note that the beading bit takes much more material out of the strip than the coving bit.
You will feel the strip being pulled into the router with greater force and if you don't restrain it, the bit won't have enough time to cut the groove properly.

Need to mill your own bead and cove strips? This economical combination bead and flute router bit is perfect for the job.

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Mail:
Vaclav Stejskal
58 Wood Ln.
Acton, MA 01720
USA
Tel: 781-481-9261

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