: Got 40 lbs. of scrap aluminum tubing from the local recycler's. It used to be
: a Ham radio antenna. Big ol' cast aluminum mounting blocks in the center
: of each tube. Got rid of the aluminum blocks, but there were wooden dowels
: inside the tubing to keep the set screws from crushing the tubing...

: No idea how to get the wood out of the center. There's 3' chunk in the middle
: of every 5' stick o' tubing. I tried driving it out with a piece of steel
: rod. No move.

You mention the option of leaving the wood in place and building what would
be a very heavy kayak. More important than the weight gain, would be the
incredible rigidity of the tubes. This leads to another , but similar
consideration. Since the scrap aluminum is from a ham radio antenna,
my guess is that it has very thick walls ? If so, it may simply be too
rigid in it's own right to assume the steep curvatures of the chines, and
gunwales in particular.

I've noticed on this forum that most builders, yourself included, are
meticulous in wood selection, be it Woodstip, S & G, or SOF stringers and ribs.

The selection of folding kayak materials is no less critical, but I've
noticed that most builders attempting this type kayak, seem to view it as a
poor substitute for the real thing, and therefore not worth the additional cost
of doing it right.

At $1.00 per foot, 3/4 X .049 ( 6061-T6) aluminum is the best all around
tubing for strength, flexibility, and aluminum insert compatibility. An
alternative is 3/4" X .035 as it is lighter, more flexible, and costs
about 10% less. It's only drawback is that it's wall thickness is a sloppy
fit with all available aluminum insert sizes.

Wall thickness is critical, not only for weight, but for the flex required
to conform to the shape of the hull. By selecting the correct building
materials, your Anas Acuta will be not just a folding kayak, but rather,
a sub 30lb. kayak capable of awesome performance.

Perhaps the stubborn wooden dowels are trying to tell you something.

Tom