Don, I can now see that you are more serious about this than what I might be. Doing full length cores under the assumptions you list gets pretty close to actually breaking real paddles. Are you perhaps also including one with 1/4" core and 3/8" cap strips? Weighing them all before breaking them... you'll get really interesting data!

It might turn out that hollow ones of equal weight are no weaker than their solid counterparts... at least this is what I would put my money on (but not much of it! ). But like you said, how much lighter can they be, that is the question!

Hmmm... you'll probably come out of this testing with the ability to build not only to predetermined weight and strength qualities, but to predetermined flexibility as well. With several levels of optional finishes. That kind of product tailoring will give the prices some nice elasticity - upwards!

: Actually, I intend to test full-length cores, tapered at the ends as in a
: paddle, and with the first 1/4" of blade laminations in - as in a
: paddle. The assumptions are that the tapered ends would be weaker without
: any blades on them; that the blades do add strength to the finished
: paddle; and that MOST of that added strength is in the first (root)
: lamination - as you add material out at the edges it doesnt significantly
: change the strength of the loom. I need data that as closely as possible
: represents actual core construction.

: I think testing the core as I intend to do will give data relevant to the
: finished paddle - not just to the core. And breaking a few paddles is no
: problem. I have at least two finished ones now that I could break -
: possibly three or four. If I know the paddle I'm building is for the test,
: I wont final sand it, shape the tips, treat the tips, or finish it. Just
: 'rough-carved'. The assumption here is that while final sanding does
: remove some material, the strength of that material removed is
: insignificant, as we are talking about a few thousandths in most cases.
: And the assumption is that the finish does not contribute to the final
: strength. Finally, and possibly the only valid assumption, is that it isnt
: worth the effort to sand and finish a paddle to be broken

: Ideally, I'd like to be able to A: Predict what the final weight of a paddle
: will be by knowing how it is to be constructed and with what materials,
: and B: To design a hollow-core of equal strength to a solid paddle, with
: significantly less weight.

: BTW, I just finished two solid WRC paddles, and thier weights are each 800
: grams - not a significant difference between the heavier of the
: laminated/hollow ones. The lightest hollow ones are significantly lighter
: - 750 and 725 respectively, so that is now the design weight. I cannot get
: it with epoxy and glass interiors...

: This is an interesting game. Jeff's science experiment will be a follow-up of
: the initial core testing, using completed paddles as above. It should
: provide some very useful data.

: Anybody want to contribute a Superior laminated pine, and a carbon-fiber? I'd
: be happy to break them