Delwin D Fandrich wrote: > > > Except for the laminated ribs being somewhat more consistent I've not > noticed much of any difference in their strength or stiffness > characteristic. Why should they be? They are made of the same wood. Well, you are the expert here on this subject matter so if you say so I buy it. I just was under the impression that when pressing and glueing laminants into a desired curviature for some useage where the laminants are parallel to whatever stresses were to be applied, that they are stronger then solid wood if the stress is in the same direction of the curve, and weaker if the stress goes against the curve. > > What about compression issues? Why should there be any more compression > stress on the wood fibers in a laminated rib than there are in a solid rib? > We've tried stressing the things every which way and have found invariably > the solid wood rib cracks or breaks before the laminate does. I can believe this for sure, laminants dont usually crack or break at all, they splinter when they fail. As far as the compression bit... dont any two wood surfaces glued in such a way that they contrain each other cross grain create compression issues when stressed ? Or are these laminants glued with grain all going the same way ? Forgive me for still being rather unitiated with all this :) > > Laminates have been used in > everything from automobile bridge members to church beams to piano rims. True, but its the direction of the laminants against whatever stresses are applied I was asking about. > If > I were making the rocking chair in question I'd want to know why the thing > was breaking. If you saw the demonstration you'd see it right away. But I suppose you can do this yourself. Glue and press say a 5 plies that are about 2 meters long into a U shape. When dry stress the U by pressing the ends together, then apart. > > Del > > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html http://www.hf.uib.no/grieg/personer/cv_RB.html
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