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Dan Thomas
 
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Default Spruce spars source ?

James Johnson wrote in message . ..
Look at 'Practical Yacht Joinery" by Fred Bingham gives instructions on building
a wooden mast. Also if using clear Douglas Fir (the actual Douglas Fir not the
substitutes that many suppliers try to sell) you can reduce skantling by 10% for
a similar strength to weight ratio.

JJ


I wish I knew where to find the engineered lumber that was
developed a few years ago. It's the lumber equivalent of plywood or
OSB or particle board. The wood is cut into long, very thin and narrow
strips (like string), laid in a mold with some resin, and compressed.
The result is a board with very straight grain, no knots or other
flaws, really consistent. A bit heavier than the lumber made from the
same wood, but just as strong or stronger. Chief drawback, as I
understand it, is the tendency to fail very suddenly when
overstressed; no warning noises.
This stuff would make dandy spars for boats, and for aircraft
wings, too. Shrinkage would be much less of a problem. The only thing
I've seen that's anywhere close is the stuff used for top and bottom
caps on engineered floor joists. Looks like plywood with the grain all
running longitudinally.

Dan

Dan