: Hi Paul, hope you don't mind some comments?

: I recommneded 3 feet for testing, as a typical loom on a GP is around 2 feet.
: The motivation was that a longer test piece requires less weight to bend
: and break, making for a more feasible set-up.

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.

: Testing real paddles would be fine, if it weren't so costly... and I'd
: consider it sinful as well - breaking a good GP! !!! Anyway, with the
: gradually widening blades many things come into play, such as thickness,
: taper, edge wood, nr of laminations, etc. Would a test involving just the
: core box really be relevant for a finished paddle. Personally, I'd resist
: the temptation of making comparisons, let alone giving estimates or
: guarantees.

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

: Yes, I'm 100% in agreement here. Finding out how to make a simple and
: economical core quickly, and with sufficient strength, is far more useful
: than knowing how to make the most resistant one, at any cost and no matter
: how long it takes.

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

: risto

: ps. There is a saying in Finland that goes (app.) " the more Cooks there
: are around the pot, the ghastlier the Soup will be" . But since I
: don't believe any of it, I am happily adding my spices into the brew...